Pyqt Signals And Slots Tutorial

In PyQt4 I have a main window which when the settings button is clicked opens the settings dialog

PyQt5 Signals and slots; PyQt5 messagebox; PyQt5 textbox; PyQt5 positioning; PyQt5 menu; PyQt5 table; PyQt5 tabs; PyQt5 horizontal layout; PyQt5 grid layout; PyQt5 input dialogs; PyQt5 file dialogs; PyQt5 load image; PyQt5 drawing and pixels; PyQt5 color dialog; PyQt5 colors; Drag and drop; PyQt5 font dialog; PyQt5 matplotlib; Webkit browser. 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. 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. Signals and Slots. Event; User’s actions. For example, a button click, selecting an item. Signal; In response to one or more events, PyQt widgets send signal. Signal does not induce any action. Slot; The signal is connected to Slot, which is a Python callable function. One signal can be connected to many slots. To establish a signal and slot connection between two widgets in a dialog, you first need to switch to Qt Designer's Edit Signals/Slots mode. To do that, you can press the F4 key, select the EditEdit Signals/Slots option in the main menu, or click on the Edit Signals/Slots button on the toolbar.

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:

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. ...

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!...

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...

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'] =...

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') ...

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...

How to use template within Django template?

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 <div> <div> {% include 'templates/child.html' with list_item=mylist.0 t=50 only %} </div> </div> child.html {{ list_item.text truncatewords:t }} UPDATE: As spectras recommended, you can use the...

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]+)'...

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...

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...

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...

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...

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( <document or array of documents>, { // options writeConcern: <document>, ordered: <boolean> } ) You may want to add the _id to the document in advance, but...

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...

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....

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]] ...

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....

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...

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...

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...

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...

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...

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...

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 does the class_weight parameter in scikit-learn work?

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)...

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 =...

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...

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('<table>') if -1 left_index: return s right_index = s.find('</table>', left_index) return s[:left_index] + remove_table(s[right_index + 8:]) There may be some blank lines inside the result....

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...

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)...

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<rad+bin_width/2.)].mean() return average_intensities #...

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....

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):...

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...

Django: html without CSS and the right text

python,html,css,django,url

Are you using the {% load staticfiles %} in your templates?

Pandas Dataframe Complex Calculation

python,python-2.7,pandas,dataframes

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...

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 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...

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,...

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...

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...

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...

C++ & Qt: Random string from an array area

c++,arrays,string,qt,random

You should use the random header. #include <random> 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...

SQLAlchemy. 2 different relationships for 1 column

Pyqt Signals And Slots Tutorial Key

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.

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

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....

The event loop is already running

Pyqt Signals And Slots Tutorial Cheat

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...

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...

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...

Calling function and passing arguments multiple times

python,function,loops

a,b,c = 1,2,3 while i<n: a,b,c = myfunction(a,b,c) i +=1 ...

• PyQt Tutorial

• PyQt Useful Resources

• Selected Reading

Unlike a console mode application, which is executed in a sequential manner, a GUI based application is event driven. Functions or methods are executed in response to user’s actions like clicking on a button, selecting an item from a collection or a mouse click etc., called events.

Widgets used to build the GUI interface act as the source of such events. Each PyQt widget, which is derived from QObject class, is designed to emit ‘signal’ in response to one or more events. The signal on its own does not perform any action. Instead, it is ‘connected’ to a ‘slot’. The slot can be any callable Python function.

In PyQt, connection between a signal and a slot can be achieved in different ways. Following are most commonly used techniques −

A more convenient way to call a slot_function, when a signal is emitted by a widget is as follows −

Suppose if a function is to be called when a button is clicked. Here, the clicked signal is to be connected to a callable function. It can be achieved in any of the following two techniques −

or

Example

In the following example, two QPushButton objects (b1 and b2) are added in QDialog window. We want to call functions b1_clicked() and b2_clicked() on clicking b1 and b2 respectively.

Pyqt Signals And Slots Tutorials

When b1 is clicked, the clicked() signal is connected to b1_clicked() function

Pyqt Signals And Slots Tutorial For Beginners

When b2 is clicked, the clicked() signal is connected to b2_clicked() function

Example

The above code produces the following output −

Output