This article mainly introduces PyQt5 daily must learn events and signals related information, has some reference value, interested partners can refer to
In this section we will explore how PyQt5's events and signals are implemented in the application.
Book: Create Desktop Apps with Python PyQt5
Events
All GUI applications are event-driven. Application events are generated primarily from users, but they can also be generated by other means, such as an Internet connection, a window manager, or a timer. When we call the exec_() method of the application, the application enters the main loop. The main loop detects various events and sends them to the event object.
Signals and slots are loosely coupled: A class which emits a signal neither knows nor cares which slots receive the signal. Qt's signals and slots mechanism ensures that if you connect a signal to a slot, the slot will be called with the signal's parameters at the right time. Signals and slots can take any number of arguments of any type. The receivers of signals are called Slots in Qt terminology. A number of standard slots are provided on Qt classes to allow you to wire together different parts of your application. However, you can also use any Python function as a slot, and therefore receive the message yourself.
In the event model, there are three participants.
- event source
- event object
- event target
An event source is a change in the state of an object that generates an event. An event object (event) is an object that encapsulates a state change in the event source. The event target is the object that wants to be notified. The event source object represents the task of processing an event to the event target.
PyQt5 uses a unique signal and slot mechanism to handle events. Signals and slots are used for communication between objects, and when a particular event occurs, the signal is fired. The slot can be any Python call. The connection to the slot is called while the signal is transmitting.
Signals & slots
Here's a simple example to demonstrate PyQt5's signal and slot.
In our example, QtGui.QLCDNumber and QtGui.QSlider will be used. we change the LCD numbers by dragging the slider.
Here, the slider's valueChanged signal is connected to the LCD's display (display) slot.
A transmitter is an object that sends a signal. The receiver is the object that receives the signal. What slots is the method of feedback to the signal.
Overwrite the system event handler. You can use any key to fire an event.
In the example below the escape key triggers an event that quits the program.
In our example, we reimplement the keyPressEvent() event handler.
If we press the Esc key on the keyboard, the application terminates.
Book: Create Desktop Apps with Python PyQt5
Event sender event send
To facilitate differentiation of multiple event sources connected to the same event target, the sender() method can be used in PyQt5.
In our example there are two buttons. Both buttons are connected to the buttonClicked() method and we respond to the clicked button by calling the sender() method.
The two buttons are connected to the same slot.
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We determine the signal source by calling the sender() method. In the application's status bar, the label of the button that was pressed is displayed.
Customized emission signals
An object created from a QObject can signal. In the following example, we'll look at how we can customize the signal sent.
We create a new signal called closeApp. This signal is emitted by the mouse press event. This signal is connected to the close() slot in QMainWindow.
Creates a Communicate class inherited from QObject, which has a property of the pyqtSignal() class.
Connect our custom closeApp signal to the close() slot in QMainWindow.
The CloseApp signal is emitted (emit) when our mouse clicks in the program window: application termination. Advanced poker strategy texas holdem.
Book: Create Desktop Apps with Python PyQt5
In PyQt4 I have a main window which when the settings button is clicked opens the settings dialog
The above works and my SettingsDialog is displayed but I cant get the setPageIndex to work
The bookSettingsBtn is a QToolButton
And the settingsStackedWidget is a QStackedWidget
At this point I am pretty confused on signals and slots and nothing I have read clears this up - if anyone can point out what I am doing wrong above and also potentially direct me to a good (beginners) guide / tutorial on signals and slots it would be greatly appreciated
I would also like to know how to make setPageIndex work as follows:
I'm not sure why you're doing the following, but that's the issue:
SettingsDialog
itself is a proper QDialog
. You don't need to instantiate another QDialog
.
Right now, you're creating an empty QDialog
and then populate it with the same ui as SettingsDialog
(i.e. setupUi(dialog)
), then you show this dialog. But.. The signal connection is for SettingsDialog
, and the dialog you're showing doesn't have that.
Basically, you don't need that extra QDialog
at all. The following should be enough:
Replace nodejs for python?
python,node.js,webserver
You might want to have a look at Tornado. It is well-documented and features built-in support for WebSockets. If you want to steer clear of the Tornado-framework, there are several Python implementations of Socket.io. Good luck!..
Python: can't access newly defined environment variables
python,bash,environment-variables
After updating your .bashrc, perform source ~/.bashrc to apply the changes. Also, merge the two BONSAI-related calls into one: export BONSAI=/home/me/Utils/bonsai_v3.2 UPDATE: It was actually an attempt to update the environment for some Eclipse-based IDE. This is a different usecase altogether. It should be described in the Eclipse help. Also,..
Create an exe with Python 3.4 using cx_Freeze
python,python-3.4,cx-freeze
Since you want to convert python script to exe have a look at py2exe
Parse text from a .txt file using csv module
python,python-2.7,parsing,csv
How about using Regular Expression def get_info(string_to_search): res_dict = {} import re find_type = re.compile('Type:[s]*[w]*') res = find_type.search(string_to_search) res_dict['Type'] = res.group(0).split(':')[1].strip() find_Status = re.compile('Status:[s]*[w]*') res = find_Status.search(string_to_search) res_dict['Status'] = res.group(0).split(':')[1].strip() find_date = re.compile('Date:[s]*[/0-9]*') res = find_date.search(string_to_search) res_dict['Date'] = res.group(0).split(':')[1].strip() res_dict['description'] =..
Pandas - Dropping multiple empty columns
python,pandas
You can just subscript the columns: df = df[df.columns[:11]] This will return just the first 11 columns or you can do: df.drop(df.columns[11:], axis=1) To drop all the columns after the 11th one..
Calling function and passing arguments multiple times
python,function,loops
a,b,c = 1,2,3 while i
How to put an image on another image in python, using ImageTk?
python,user-interface,tkinter
Just use photoshop or G.I.M.P. I assure you, doing it that way will be much simpler and less redundant than essentially getting Tkinter to photo edit for you (not to mention what you're talking about is just bad practice when it comes to coding) Anyways, I guess if you really..
How do variables inside python modules work?
python,module,python-module
The convention is to declare constants in modules as variables written in upper-case (Python style guide: https://www.python.org/dev/peps/pep-0008/#global-variable-names). But there's no way to prevent someone else to re-declare such a variable -- thus ignoring conventions -- when importing a module. There are two ways of working around this when importing modules..
Python Popen - wait vs communicate vs CalledProcessError
python,python-2.7,error-handling,popen
about the deadlock: It is safe to use stdout=PIPE and wait() together iff you read from the pipe. .communicate() does the reading and calls wait() for you about the memory: if the output can be unlimited then you should not use .communicate() that accumulates all output in memory. what..
Twilio Client Python not Working in IOS Browser
javascript,python,ios,flask,twilio
Twilio developer evangelist here. Twilio Client uses WebRTC and falls back to Flash in order to make web browsers into phones. Unfortunately Safari on iOS supports neither WebRTC nor Flash so Twilio Client cannot work within any browser on iOS. It is possible to build an iOS application to use..
SQLAlchemy. 2 different relationships for 1 column
python,sqlalchemy
I'm afraid you can't do it like this. I suggest you have just one relationship users and validate the insert queries.
how to enable a entry by clicking a button in Tkinter?
python,tkinter
You need to use the configure method of each widget: def rakhi(): entry1.configure(state='normal') entry2.configure(state='normal') ..
How to use template within Django template?
Python Signal Module
python,html,django,templates,django-1.4
You can use the include tag in order to supply the included template with a consistent variable name: For example: parent.html
How do I read this list and parse it?
python,list
Your list contains one dictionary you can access the data inside like this : >>> yourlist[0]['popularity'] 2354 [0] for the first item in the list (the dictionary). ['popularity'] to get the value associated to the key 'popularity' in the dictionary..
Python recursive function not recursing
python,recursion
Afraid I don't know much about python, but I can probably help you with the algorithm. The encoding process repeats the following: multiply the current total by 17 add a value (a = 1, b = 2, .., z = 26) for the next letter to the total So at..
Peewee: reducing where conditionals break after a certain length
python,peewee
Try ..where(SomeTable.BIN.in_(big_list)) PeeWee has restrictions as to what can be used in their where clause in order to work with the library. http://docs.peewee-orm.com/en/latest/peewee/querying.html#query-operators..
odoo v8 - Field(s) `arch` failed against a constraint: Invalid view definition
python,xml,view,odoo,add-on
You have made silly mistake in defining _columns. _colums is not valid dictionary name for fields structure. Replace this by _columns and restart service and update module. ..
Identify that a string could be a datetime object
python,regex,algorithm,python-2.7,datetime
What about fuzzyparsers: Sample inputs: jan 12, 2003 jan 5 2004-3-5 +34 -- 34 days in the future (relative to todays date) -4 -- 4 days in the past (relative to todays date) Example usage: >>> from fuzzyparsers import parse_date >>> parse_date('jun 17 2010') # my youngest son's birthday datetime.date(2010,..
Python: histogram/ binning data from 2 arrays.
python,histogram,large-files
if you only need to do this for a handful of points, you could do something like this. If intensites and radius are numpy arrays of your data: bin_width = 0.1 # Depending on how narrow you want your bins def get_avg(rad): average_intensity = intensities[(radius>=rad-bin_width/2.) & (radius
Django: html without CSS and the right text
python,html,css,django,url
Are you using the {% load staticfiles %} in your templates?
sys.argv in a windows environment
python,windows,python-3.x
You are calling the script wrong Bring up a cmd (command line prompt) and type: cd C:/Users/user/PycharmProjects/helloWorld/ module_using_sys.py we are arguments And you will get the correct output..
C++ & Qt: Random string from an array area
c++,arrays,string,qt,random
You should use the random header. #include std::default_random_engine generator; std::uniform_int_distribution dist(0, 5); int StringIndex = dist(generator); std::string ChosenString = characters[StringIndex]; The above will generate a random index into your array. If you want to limit the range, change the constructor of dist, for example (dist(0,2) would only allow for..
Strange Behavior: Floating Point Error after Appending to List
python,python-2.7,behavior
Short answer: your correct doesn't work. Long answer: The binary floating-point formats in ubiquitous use in modern computers and programming languages cannot represent most numbers like 0.1, just like no terminating decimal representation can represent 1/3. Instead, when you write 0.1 in your source code, Python automatically translates this to..
The event loop is already running
python,python-3.x,pyqt,pyqt4
I think the problem is with your start.py file. You have a function refreshgui which re imports start.py import will run every part of the code in the file. It is customary to wrap the main functionality in an 'if __name__ '__main__': to prevent code from being run on..
Count function counting only last line of my list
python,python-2.7
I don't know what you are exactly trying to achieve but if you are trying to count R and K in the string there are more elegant ways to achieve it. But for your reference I had modified your code. N = int(raw_input()) s = [] for i in range(N):..
Inconsistency between gaussian_kde and density integral sum
python,numpy,kernel-density
As stated in my comment, this is an issue with kernel density support. The Gaussian kernel has infinite support. Even fit on data with a specific range the range of the Gaussian kernel will be from negative to positive infinity. That being said the large majority of the density will..
Spring-integration scripting with Python
python,spring-integration,jython
This is a bug in Spring Integration; I have opened a JIRA Issue. if (variables != null) { result = scriptEngine.eval(script, new SimpleBindings(variables)); } else { result = scriptEngine.eval(script); } When the first branch of the if test is taken, the result variable is added to the SimpleBindings object, and..
Displaying a 32-bit image with NaN values (ImageJ)
python,image-processing,imagej
The display range of your image might not be set correctly. Try outputImp.resetDisplayRange() or outputImp.setDisplayRange(Stats.min, Stats.max) See the ImagePlus javadoc for more info..
Matplotlib: Plot the result of an SQL query
python,sql,matplotlib,plot
Take this for a starter code : import numpy as np import matplotlib.pyplot as plt from sqlalchemy import create_engine import _mssql fig = plt.figure() ax = fig.add_subplot(111) engine = create_engine('mssql+pymssql://**:****@127.0.0.1:1433/AffectV_Test') connection = engine.connect() result = connection.execute('SELECT Campaign_id, SUM(Count) AS Total_Count FROM Impressions GROUP BY Campaign_id') ## the data data =..
How to remove structure with python from this case?python,python-2.7
It's complicated to use regex, a stupid way I suggested: def remove_table(s): left_index = s.find('') if -1 left_index: return s right_index = s.find('
How to change the IP address of Amazon EC2 instance using boto library
python,amazon-web-services,boto
Make sure you have set properly with ~/.boto and connect to aws, have the boto module ready in python. If not, go through this first: Getting Started with Boto For example, you need assign a new EIP 54.12.23.34 to the instance i-12345678 Make sure, EIP has been allocated(existed) and you..
Sort when values are None or empty strings python
python,list,sorting,null
If you want the None and ' values to appear last, you can have your key function return a tuple, so the list is sorted by the natural order of that tuple. The tuple has the form (is_none, is_empty, value); this way, the tuple for a None value will be..
Python Slots And Signals Functions
Python np.delete issue
python,numpy
Don't call np.delete in a loop. It would be quicker to use boolean indexing: In [6]: A[X.astype(bool).any(axis=0)] Out[6]: array([[3, 4, 5]]) X.astype(bool) turns 0 into False and any non-zero value into True: In [9]: X.astype(bool).any(axis=0) Out[9]: array([False, True, False], dtype=bool) the call to .any(axis=0) returns True if any value in..
Sum of two variables in RobotFramework
python,automated-tests,robotframework
By default variables are string in Robot. So your first two statements are assigning strings like 'xx,yy' to your vars. Then 'evaluate' just execute your statement as Python would do. So, adding your two strings with commas will produce a list: $ python >>> 1,2+3,4 (1, 5, 4) So you..
How to check for multiple attributes in a list
python,python-2.7
You can create a set holding the different IDs and then compare the size of that set to the total number of quests. The difference tells you how many IDs are duplicated. Same for names. Something like this (untested): def test_quests(quests): num_total = len(quests) different_ids = len(set((q.ID for q in..
Find the tf-idf score of specific words in documents using sklearn
python,scikit-learn,tf-idf
Yes. See .vocabulary_ on your fitted/transformed TF-IDF vectorizer. In [1]: from sklearn.datasets import fetch_20newsgroups In [2]: data = fetch_20newsgroups(categories=['rec.autos']) In [3]: from sklearn.feature_extraction.text import TfidfVectorizer In [4]: cv = TfidfVectorizer() In [5]: X = cv.fit_transform(data.data) In [6]: cv.vocabulary_ It is a dictionary of the form: {word : column index in..
trying to understand LSH through the sample python code
python,similarity,locality-sensitive-hash
a. It's a left shift: https://docs.python.org/2/reference/expressions.html#shifting-operations It shifts the bits one to the left. b. Note that ^ is not the 'to the power of' but 'bitwise XOR' in Python. c. As the comment states: it defines 'number of bits per signature' as 2**10 → 1024 d. The lines calculate..
group indices of list in list of lists
python,list
Use collections.OrderedDict: from collections import OrderedDict od = OrderedDict() lst = [2, 0, 1, 1, 3, 2, 1, 2] for i, x in enumerate(lst): od.setdefault(x, []).append(i) .. >>> od.values() [[0, 5, 7], [1], [2, 3, 6], [4]] ..
represent an index inside a list as x,y in python
python,list,numpy,multidimensional-array
According to documentation of numpy.reshape , it returns a new array object with the new shape specified by the parameters (given that, with the new shape, the amount of elements in the array remain unchanged) , without changing the shape of the original object, so when you are calling the..
Python - Opening and changing large text files
python,replace,out-of-memory,large-files
You need to read one bite per iteration, analyze it and then write to another file or to sys.stdout. Try this code: mesh = open('file.mesh', 'r') mesh_out = open('file-1.mesh', 'w') c = mesh.read(1) if c: mesh_out.write('{') else: exit(0) while True: c = mesh.read(1) if c ': break if c..
ctypes error AttributeError symbol not found, OS X 10.7.5
python,c++,ctypes
Your first problem is C++ name mangling. If you run nm on your .so file you will get something like this: nm test.so 0000000000000f40 T __Z3funv U _printf U dyld_stub_binder If you mark it as C style when compiled with C++: #ifdef __cplusplus extern 'C' char fun() #else char fun(void)..
Can't get value from xpath python
python,html,xpath,web-scraping,html-parsing
The values in the table are generated with the help of javascript being executed in the browser. One option to approach it is to automate a browser via selenium, e.g. a headless PhantomJS: >>> from selenium import webdriver >>> >>> driver = webdriver.PhantomJS() >>> driver.get('http://www.tabele-kalorii.pl/kalorie,Actimel-cytryna-miod-Danone.html') >>> >>> table = driver.find_element_by_xpath(u'//table[tbody/tr/td/h3..
MySQLdb Python - Still getting error when using CREATE TABLE IF NOT EXISTS
python,mysql
MySQL is actually throwing a warning rather that an error. You can suppress mysql warnings like this : import MySQLdb as mdb from warnings import filterwarnings filterwarnings('ignore', category = mdb.Warning) Now the mysql warnings will be gone. But mysql errors will be shown as usual Read more about warnings at..
Using counter on array for one value while keeping index of other values
python,collections
To count how often one value occurs and at the same time you want to select those values, you'd simply select those values and count how many you selected: fruits = [f for f in foods if f[0] 'fruit'] fruit_count = len(fruits) If you need to do this for..
REGEX python find previous string
Creates a Communicate class inherited from QObject, which has a property of the pyqtSignal() class.
Connect our custom closeApp signal to the close() slot in QMainWindow.
The CloseApp signal is emitted (emit) when our mouse clicks in the program window: application termination. Advanced poker strategy texas holdem.
Book: Create Desktop Apps with Python PyQt5
In PyQt4 I have a main window which when the settings button is clicked opens the settings dialog
The above works and my SettingsDialog is displayed but I cant get the setPageIndex to work
The bookSettingsBtn is a QToolButton
And the settingsStackedWidget is a QStackedWidget
At this point I am pretty confused on signals and slots and nothing I have read clears this up - if anyone can point out what I am doing wrong above and also potentially direct me to a good (beginners) guide / tutorial on signals and slots it would be greatly appreciated
I would also like to know how to make setPageIndex work as follows:
I'm not sure why you're doing the following, but that's the issue:
SettingsDialog
itself is a proper QDialog
. You don't need to instantiate another QDialog
.
Right now, you're creating an empty QDialog
and then populate it with the same ui as SettingsDialog
(i.e. setupUi(dialog)
), then you show this dialog. But.. The signal connection is for SettingsDialog
, and the dialog you're showing doesn't have that.
Basically, you don't need that extra QDialog
at all. The following should be enough:
Replace nodejs for python?
python,node.js,webserver
You might want to have a look at Tornado. It is well-documented and features built-in support for WebSockets. If you want to steer clear of the Tornado-framework, there are several Python implementations of Socket.io. Good luck!..
Python: can't access newly defined environment variables
python,bash,environment-variables
After updating your .bashrc, perform source ~/.bashrc to apply the changes. Also, merge the two BONSAI-related calls into one: export BONSAI=/home/me/Utils/bonsai_v3.2 UPDATE: It was actually an attempt to update the environment for some Eclipse-based IDE. This is a different usecase altogether. It should be described in the Eclipse help. Also,..
Create an exe with Python 3.4 using cx_Freeze
python,python-3.4,cx-freeze
Since you want to convert python script to exe have a look at py2exe
Parse text from a .txt file using csv module
python,python-2.7,parsing,csv
How about using Regular Expression def get_info(string_to_search): res_dict = {} import re find_type = re.compile('Type:[s]*[w]*') res = find_type.search(string_to_search) res_dict['Type'] = res.group(0).split(':')[1].strip() find_Status = re.compile('Status:[s]*[w]*') res = find_Status.search(string_to_search) res_dict['Status'] = res.group(0).split(':')[1].strip() find_date = re.compile('Date:[s]*[/0-9]*') res = find_date.search(string_to_search) res_dict['Date'] = res.group(0).split(':')[1].strip() res_dict['description'] =..
Pandas - Dropping multiple empty columns
python,pandas
You can just subscript the columns: df = df[df.columns[:11]] This will return just the first 11 columns or you can do: df.drop(df.columns[11:], axis=1) To drop all the columns after the 11th one..
Calling function and passing arguments multiple times
python,function,loops
a,b,c = 1,2,3 while i
How to put an image on another image in python, using ImageTk?
python,user-interface,tkinter
Just use photoshop or G.I.M.P. I assure you, doing it that way will be much simpler and less redundant than essentially getting Tkinter to photo edit for you (not to mention what you're talking about is just bad practice when it comes to coding) Anyways, I guess if you really..
How do variables inside python modules work?
python,module,python-module
The convention is to declare constants in modules as variables written in upper-case (Python style guide: https://www.python.org/dev/peps/pep-0008/#global-variable-names). But there's no way to prevent someone else to re-declare such a variable -- thus ignoring conventions -- when importing a module. There are two ways of working around this when importing modules..
Python Popen - wait vs communicate vs CalledProcessError
python,python-2.7,error-handling,popen
about the deadlock: It is safe to use stdout=PIPE and wait() together iff you read from the pipe. .communicate() does the reading and calls wait() for you about the memory: if the output can be unlimited then you should not use .communicate() that accumulates all output in memory. what..
Twilio Client Python not Working in IOS Browser
javascript,python,ios,flask,twilio
Twilio developer evangelist here. Twilio Client uses WebRTC and falls back to Flash in order to make web browsers into phones. Unfortunately Safari on iOS supports neither WebRTC nor Flash so Twilio Client cannot work within any browser on iOS. It is possible to build an iOS application to use..
SQLAlchemy. 2 different relationships for 1 column
python,sqlalchemy
I'm afraid you can't do it like this. I suggest you have just one relationship users and validate the insert queries.
how to enable a entry by clicking a button in Tkinter?
python,tkinter
You need to use the configure method of each widget: def rakhi(): entry1.configure(state='normal') entry2.configure(state='normal') ..
How to use template within Django template?
Python Signal Module
python,html,django,templates,django-1.4
You can use the include tag in order to supply the included template with a consistent variable name: For example: parent.html
How do I read this list and parse it?
python,list
Your list contains one dictionary you can access the data inside like this : >>> yourlist[0]['popularity'] 2354 [0] for the first item in the list (the dictionary). ['popularity'] to get the value associated to the key 'popularity' in the dictionary..
Python recursive function not recursing
python,recursion
Afraid I don't know much about python, but I can probably help you with the algorithm. The encoding process repeats the following: multiply the current total by 17 add a value (a = 1, b = 2, .., z = 26) for the next letter to the total So at..
Peewee: reducing where conditionals break after a certain length
python,peewee
Try ..where(SomeTable.BIN.in_(big_list)) PeeWee has restrictions as to what can be used in their where clause in order to work with the library. http://docs.peewee-orm.com/en/latest/peewee/querying.html#query-operators..
odoo v8 - Field(s) `arch` failed against a constraint: Invalid view definition
python,xml,view,odoo,add-on
You have made silly mistake in defining _columns. _colums is not valid dictionary name for fields structure. Replace this by _columns and restart service and update module. ..
Identify that a string could be a datetime object
python,regex,algorithm,python-2.7,datetime
What about fuzzyparsers: Sample inputs: jan 12, 2003 jan 5 2004-3-5 +34 -- 34 days in the future (relative to todays date) -4 -- 4 days in the past (relative to todays date) Example usage: >>> from fuzzyparsers import parse_date >>> parse_date('jun 17 2010') # my youngest son's birthday datetime.date(2010,..
Python: histogram/ binning data from 2 arrays.
python,histogram,large-files
if you only need to do this for a handful of points, you could do something like this. If intensites and radius are numpy arrays of your data: bin_width = 0.1 # Depending on how narrow you want your bins def get_avg(rad): average_intensity = intensities[(radius>=rad-bin_width/2.) & (radius
Django: html without CSS and the right text
python,html,css,django,url
Are you using the {% load staticfiles %} in your templates?
sys.argv in a windows environment
python,windows,python-3.x
You are calling the script wrong Bring up a cmd (command line prompt) and type: cd C:/Users/user/PycharmProjects/helloWorld/ module_using_sys.py we are arguments And you will get the correct output..
C++ & Qt: Random string from an array area
c++,arrays,string,qt,random
You should use the random header. #include std::default_random_engine generator; std::uniform_int_distribution dist(0, 5); int StringIndex = dist(generator); std::string ChosenString = characters[StringIndex]; The above will generate a random index into your array. If you want to limit the range, change the constructor of dist, for example (dist(0,2) would only allow for..
Strange Behavior: Floating Point Error after Appending to List
python,python-2.7,behavior
Short answer: your correct doesn't work. Long answer: The binary floating-point formats in ubiquitous use in modern computers and programming languages cannot represent most numbers like 0.1, just like no terminating decimal representation can represent 1/3. Instead, when you write 0.1 in your source code, Python automatically translates this to..
The event loop is already running
python,python-3.x,pyqt,pyqt4
I think the problem is with your start.py file. You have a function refreshgui which re imports start.py import will run every part of the code in the file. It is customary to wrap the main functionality in an 'if __name__ '__main__': to prevent code from being run on..
Count function counting only last line of my list
python,python-2.7
I don't know what you are exactly trying to achieve but if you are trying to count R and K in the string there are more elegant ways to achieve it. But for your reference I had modified your code. N = int(raw_input()) s = [] for i in range(N):..
Inconsistency between gaussian_kde and density integral sum
python,numpy,kernel-density
As stated in my comment, this is an issue with kernel density support. The Gaussian kernel has infinite support. Even fit on data with a specific range the range of the Gaussian kernel will be from negative to positive infinity. That being said the large majority of the density will..
Spring-integration scripting with Python
python,spring-integration,jython
This is a bug in Spring Integration; I have opened a JIRA Issue. if (variables != null) { result = scriptEngine.eval(script, new SimpleBindings(variables)); } else { result = scriptEngine.eval(script); } When the first branch of the if test is taken, the result variable is added to the SimpleBindings object, and..
Displaying a 32-bit image with NaN values (ImageJ)
python,image-processing,imagej
The display range of your image might not be set correctly. Try outputImp.resetDisplayRange() or outputImp.setDisplayRange(Stats.min, Stats.max) See the ImagePlus javadoc for more info..
Matplotlib: Plot the result of an SQL query
python,sql,matplotlib,plot
Take this for a starter code : import numpy as np import matplotlib.pyplot as plt from sqlalchemy import create_engine import _mssql fig = plt.figure() ax = fig.add_subplot(111) engine = create_engine('mssql+pymssql://**:****@127.0.0.1:1433/AffectV_Test') connection = engine.connect() result = connection.execute('SELECT Campaign_id, SUM(Count) AS Total_Count FROM Impressions GROUP BY Campaign_id') ## the data data =..
How to remove structure with python from this case?python,python-2.7
It's complicated to use regex, a stupid way I suggested: def remove_table(s): left_index = s.find('') if -1 left_index: return s right_index = s.find('
How to change the IP address of Amazon EC2 instance using boto library
python,amazon-web-services,boto
Make sure you have set properly with ~/.boto and connect to aws, have the boto module ready in python. If not, go through this first: Getting Started with Boto For example, you need assign a new EIP 54.12.23.34 to the instance i-12345678 Make sure, EIP has been allocated(existed) and you..
Sort when values are None or empty strings python
python,list,sorting,null
If you want the None and ' values to appear last, you can have your key function return a tuple, so the list is sorted by the natural order of that tuple. The tuple has the form (is_none, is_empty, value); this way, the tuple for a None value will be..
Python Slots And Signals Functions
Python np.delete issue
python,numpy
Don't call np.delete in a loop. It would be quicker to use boolean indexing: In [6]: A[X.astype(bool).any(axis=0)] Out[6]: array([[3, 4, 5]]) X.astype(bool) turns 0 into False and any non-zero value into True: In [9]: X.astype(bool).any(axis=0) Out[9]: array([False, True, False], dtype=bool) the call to .any(axis=0) returns True if any value in..
Sum of two variables in RobotFramework
python,automated-tests,robotframework
By default variables are string in Robot. So your first two statements are assigning strings like 'xx,yy' to your vars. Then 'evaluate' just execute your statement as Python would do. So, adding your two strings with commas will produce a list: $ python >>> 1,2+3,4 (1, 5, 4) So you..
How to check for multiple attributes in a list
python,python-2.7
You can create a set holding the different IDs and then compare the size of that set to the total number of quests. The difference tells you how many IDs are duplicated. Same for names. Something like this (untested): def test_quests(quests): num_total = len(quests) different_ids = len(set((q.ID for q in..
Find the tf-idf score of specific words in documents using sklearn
python,scikit-learn,tf-idf
Yes. See .vocabulary_ on your fitted/transformed TF-IDF vectorizer. In [1]: from sklearn.datasets import fetch_20newsgroups In [2]: data = fetch_20newsgroups(categories=['rec.autos']) In [3]: from sklearn.feature_extraction.text import TfidfVectorizer In [4]: cv = TfidfVectorizer() In [5]: X = cv.fit_transform(data.data) In [6]: cv.vocabulary_ It is a dictionary of the form: {word : column index in..
trying to understand LSH through the sample python code
python,similarity,locality-sensitive-hash
a. It's a left shift: https://docs.python.org/2/reference/expressions.html#shifting-operations It shifts the bits one to the left. b. Note that ^ is not the 'to the power of' but 'bitwise XOR' in Python. c. As the comment states: it defines 'number of bits per signature' as 2**10 → 1024 d. The lines calculate..
group indices of list in list of lists
python,list
Use collections.OrderedDict: from collections import OrderedDict od = OrderedDict() lst = [2, 0, 1, 1, 3, 2, 1, 2] for i, x in enumerate(lst): od.setdefault(x, []).append(i) .. >>> od.values() [[0, 5, 7], [1], [2, 3, 6], [4]] ..
represent an index inside a list as x,y in python
python,list,numpy,multidimensional-array
According to documentation of numpy.reshape , it returns a new array object with the new shape specified by the parameters (given that, with the new shape, the amount of elements in the array remain unchanged) , without changing the shape of the original object, so when you are calling the..
Python - Opening and changing large text files
python,replace,out-of-memory,large-files
You need to read one bite per iteration, analyze it and then write to another file or to sys.stdout. Try this code: mesh = open('file.mesh', 'r') mesh_out = open('file-1.mesh', 'w') c = mesh.read(1) if c: mesh_out.write('{') else: exit(0) while True: c = mesh.read(1) if c ': break if c..
ctypes error AttributeError symbol not found, OS X 10.7.5
python,c++,ctypes
Your first problem is C++ name mangling. If you run nm on your .so file you will get something like this: nm test.so 0000000000000f40 T __Z3funv U _printf U dyld_stub_binder If you mark it as C style when compiled with C++: #ifdef __cplusplus extern 'C' char fun() #else char fun(void)..
Can't get value from xpath python
python,html,xpath,web-scraping,html-parsing
The values in the table are generated with the help of javascript being executed in the browser. One option to approach it is to automate a browser via selenium, e.g. a headless PhantomJS: >>> from selenium import webdriver >>> >>> driver = webdriver.PhantomJS() >>> driver.get('http://www.tabele-kalorii.pl/kalorie,Actimel-cytryna-miod-Danone.html') >>> >>> table = driver.find_element_by_xpath(u'//table[tbody/tr/td/h3..
MySQLdb Python - Still getting error when using CREATE TABLE IF NOT EXISTS
python,mysql
MySQL is actually throwing a warning rather that an error. You can suppress mysql warnings like this : import MySQLdb as mdb from warnings import filterwarnings filterwarnings('ignore', category = mdb.Warning) Now the mysql warnings will be gone. But mysql errors will be shown as usual Read more about warnings at..
Using counter on array for one value while keeping index of other values
python,collections
To count how often one value occurs and at the same time you want to select those values, you'd simply select those values and count how many you selected: fruits = [f for f in foods if f[0] 'fruit'] fruit_count = len(fruits) If you need to do this for..
REGEX python find previous string
python,regex,string
Updated: This will check for the existence of a sentence followed by special characters. It returns false if there are no special characters, and your original sentence is in capture group 1. Updated Regex101 Example r'(.*[w])([^w]+)' Alternatively (without a second capture group): Regex101 Example - no second capture group r'(.*[w])(?:[^w]+)'..
In sklearn, does a fitted pipeline reapply every transform?
python,scikit-learn,pipeline,feature-selection
The pipeline calls transform on the preprocessing and feature selection steps if you call pl.predict. That means that the features selected in training will be selected from the test data (the only thing that makes sense here). It is unclear what you mean by 'apply' here. Nothing new will be..
SyntaxError: invalid syntax?
python,syntax
Check the code before the print line for errors. This can be caused by an error in a previous line; for example: def x(): y = [ print 'hello' x() This produces the following error: File 'E:Pythontest.py', line 14 print 'hello' ^ SyntaxError: invalid syntax When clearly the error is..
How does the class_weight parameter in scikit-learn work?
Pyside2 Signal Slot
python,scikit-learn
First off, it might not be good to just go by recall alone. You can simply achieve a recall of 100% by classifying everything as the positive class. I usually suggest using AUC for selecting parameters, and then finding a threshold for the operating point (say a given precision level)..
Inserting a variable in MongoDB specifying _id field
python,mongodb,pymongo
Insert only accepts a final document or an array of documents, and an optional object which contains additional options for the collection. db.collection.insert( , { // options writeConcern: , ordered: } ) You may want to add the _id to the document in advance, but..
Pandas Dataframe Complex Calculation
python,python-2.7,pandas,dataframes
Python Signal Example
I believe the following does what you want: In [24]: df['New_Col'] = df['ActualCitations']/pd.rolling_sum(df['totalPubs'].shift(), window=2) df Out[24]: Year totalPubs ActualCitations New_Col 0 1994 71 191.002034 NaN 1 1995 77 2763.911781 NaN 2 1996 69 2022.374474 13.664692 3 1997 78 3393.094951 23.240376 So the above uses rolling_sum and shift to generate the..