There are several ways to present the output of a program; data can be printed in a human-readable form, or written to a file for future use. This chapter will discuss some of the possibilities. A third way is using the write method of file objects; the standard output file can be referenced as sys.
See the Library Reference for more information on this. There are several ways to format output. To use formatted string literalsbegin a string with f or F before the opening quotation mark or triple quotation mark. The str. Finally, you can do all the string handling yourself by using string slicing and concatenation operations to create any layout you can imagine.
The string type has some methods that perform useful operations for padding strings to a given column width. The str function is meant to return representations of values which are fairly human-readable, while repr is meant to generate representations which can be read by the interpreter or will force a SyntaxError if there is no equivalent syntax.
Many values, such as numbers or structures like lists and dictionaries, have the same representation using either function. Strings, in particular, have two distinct representations. An optional format specifier can follow the expression. This allows greater control over how the value is formatted.
The following example rounds pi to three places after the decimal:. Passing an integer after the ':' will cause that field to be a minimum number of characters wide.Python OOP Tutorial 1: Classes and Instances
This is useful for making columns line up. Other modifiers can be used to convert the value before it is formatted. For a reference on these format specifications, see the reference guide for the Format Specification Mini-Language.
Basic usage of the str. The brackets and characters within them called format fields are replaced with the objects passed into the str. A number in the brackets can be used to refer to the position of the object passed into the str.
If keyword arguments are used in the str. This can be done by simply passing the dict and using square brackets '' to access the keys. This is particularly useful in combination with the built-in function varswhich returns a dictionary containing all local variables.Help Needed This website is free of annoying ads.
We want to keep it like this. Possible Problems If you are a beginner in Python, there might be some problems with understanding certain Python constructs in the our main tutorial on this page: If you have problems understanding about the lambda construct, we recommend our chapter Lambda, filter, reduce and map Most probably you are familiar with functions, if not we suggest reading the chapter Functions Entries "Every exit is an entry somewhere else.
Jef Raskin, the human-computer interface expert, who started the Macintosh project for Apple, said: "A computer shall not harm your work or, through inaction, allow your work to come to harm. You can help with your donation: The need for donations Job Applications Python Lecturer bodenseo is looking for a new trainer and software developper. You need to live in Germany and know German. Find out more! CSS-help needed! We urgently need help to improve our css style sheets, especially to improve the look when printing!
Best would be, if we find somebody who wants to do it for free to support our website. But we could also pay something. Please contact usif you think that you could be of help!
A fast and efficient approach to learn program Python and Tkinter consists in attending a classroom training course by Bernd Klein at Bodenseo. Quote of the Day: Man is the best computer we can put aboard a spacecraft Wernher von Braun Graphical User Interface A graphical user interface GUI is a type of user interface that allows users to interact with electronic devices in a graphical way, i.
Originally interactive user interfaces to computers were not graphical, they were text oriented and usually consisted of commands, which had to be remembered.
The DOS operating system from Microsoft and the Bourne shell under Linux are examples of such user-computer interfaces.This Tkinter tutorial blog will help you start learning about the Tkinter library in Python and give you an in-depth insight into how Python is used to create Graphical User Interfaces GUI applications.
The number of applications of Tkinter is endless and it is a very popular and easy library to learn. In this Tkinter Tutorial, we will be covering the following concepts:. They are used to perform different tasks in the desktops, laptops and other electronic devices. We are going to learn how to create those type of apps. Well, it is a personal preference that I prefer GUI over command line.
Not that there is something wrong with the command line but I prefer more intuitive and interactive applications with a lot of visuals.
What do you prefer? Head to the comment section and let me know. Next up on this Tkinter tutorial blog, let us check out the Python libraries that are present for designing our own GUI.
Python has a plethora of libraries and these 4 stands out mainly when it comes to GUI. There are as follows:. Among all of these, Tkinter is preferred by a LOT of learners and developers just because of how simple and easy it is.
I am sure you will have the same opinion in a while as well. Next up on this Tkinter tutorial blog, let us check out what Tkinter actually is. Another advice for you guys is to not blindly copy the code. Try to write by modifying it as you like and then observing and understanding the resulting changes. Next up on this Tkinter tutorial blog, let us check out the fundamentals of Tkinter so that we can go about creating our own GUIs. Consider the following diagram, it shows how an application actually executes in Tkinter:.
To start out with, we first import the Tkinter model. Followed by that, we create the main window. It is in this window that we are performing operations and displaying visuals and everything basically. Later, we add the widgets and lastly we enter the main event loop.
If you noticed, there are 2 keywords here that you might not know at this point. These are the 2 keywords:. An event loop is basically telling the code to keep displaying the window until we manually close it. It runs in an infinite loop in the back-end. As you can see, we are importing the Tkinter package and defining a window. Followed by that, we are giving a window title which is shown on the title tab whenever you open an application.
I was wondering if there were more efficient ways of doing this,or perhaps ways that make more aesthetically pleasing grids with less code. My code is in working order and does as it says on the label, I also implemented a system that does not allow for incorrect inputs.
You know about list-comprehensions, but you use a default value before filling your rows with zeroes. You could do it in one go:. The for loop in Python is meant to be used to iterate directly over elements rather than indices:. It is bad practice to rely on global to share data accros functions.
You should define those function to accept parameters instead. This let you also extract input handling from your grid creation function which is also better as let you have a single responsibility per function:. Python have else clauses that are executed when the try part succeeded.
The aim is to reduce the amount of code protected by the try to avoid catching unexpected exceptions. In your case, you could change that part to:. Biggest part of your code is prompting user for input. I'd say that you should move that to a separate function. That way, you'd be able to reuse user-prompting part. Also, grid-generating part would be only generating grid, having 1 responsibility not 2, as it is now.
This question was tagged connect-fourhence my shape parameters. Those could easily be changed to the variables input by the user which you should handle in a separate function. Note that this will perform slower than the other presented solutions for smaller shape values. The speed improvement kicks in with larger sizes. You could use str. Also, there's a better way to check if the user inputs a non-integer: str. Sign up to join this community.
The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered.The Grid geometry manager puts the widgets in a 2-dimensional table. The grid manager is the most flexible of the geometry managers in Tkinter. The grid manager is especially convenient to use when designing dialog boxes.
Instead of using lots of extra frames to get the packing to work, you can in most cases simply pour all the widgets into a single container widget, and use the grid manager to get them all where you want them.
I tend to use two containers; one for the dialog body, and one for the button box at the bottom. Creating this layout using the pack manager is possible, but it takes a number of extra frame widgets, and a lot of work to make things look good.
If you use the grid manager instead, you only need one call per widget to get everything laid out properly see next section for the code needed to create this layout. Warning: Never mix grid and pack in the same master window. Tkinter will happily spend the rest of your lifetime trying to negotiate a solution that both managers are happy with. Instead of waiting, kill the application, and take another look at your code.
A common mistake is to use the wrong parent for some of the widgets. Using the grid manager is easy. Just create the widgets, and use the grid method to tell the manager in which row and column to place them. Empty rows and columns are ignored. The result would have been the same if you had placed the widgets in row 10 and 20 instead. Note that the widgets are centered in their cells. You can use the sticky option to change this; this option takes one or more values from the set NSEW.
To align the labels to the left border, you could use W west :. You can also have the widgets span more than one cell.
The columnspan option is used to let a widget span more than one column, and the rowspan option lets it span more than one row.
The following code creates the layout shown in the previous section:. There are plenty of things to note in this example. First, no position is specified for the label widgets.The tkinter. The above three functions provide dialogs that prompt the user to enter a value of the desired type. The following classes and functions provide file dialog windows that combine a native look-and-feel with configuration options to customize behaviour.
The following keyword arguments are applicable to the classes and functions listed below:. The above two functions create an Open dialog and return the opened file object s in read-only mode. Create a SaveAs dialog and return a file object opened in write-only mode. The above two functions create an Open dialog and return the selected filename s that correspond to existing file s.
Create a SaveAs dialog and return the selected filename. These do not emulate the native look-and-feel of the platform. Test whether or not the selection points to a valid file that is not a directory. Confirmation is required if an already existing file is selected.
Modules tkinter. Override for custom button layouts. The following keyword arguments are applicable to the classes and functions listed below: parent - the window to place the dialog on top of.
Note The FileDialog class should be subclassed for custom event handling and behaviour. See also Modules tkinter. Table of Contents Tkinter Dialogs tkinter. The Python Software Foundation is a non-profit corporation. Please donate. Last updated on Apr 15, Found a bug? Created using Sphinx 2.Out of all the GUI methods, tkinter is the most commonly used method.
Python with tkinter is the fastest and easiest way to create the GUI applications. Creating a GUI using tkinter is an easy task. To create a tkinter app:. Importing tkinter is same as importing any other module in the Python code. Note that the name of the module in Python 2. There are two main methods used which the user needs to remember while creating the Python application with GUI. There are mainly three geometry manager classes class. There are a number of widgets which you can put in your tkinter application.
Some of the major widgets are explained below:. There are number of options which are used to change the format of the Buttons. Number of options can be passed as parameters separated by commas.
Some of them are listed below. Output: Canvas: It is used to draw pictures and other complex layout like graphics, text and widgets. The general syntax is:. There are number of options which are used to change the format of the widget.
Python | grid() method in Tkinter
Output: CheckButton: To select any number of options by displaying a number of options to a user as toggle buttons. Attach a File:nd color. Output: Entry: It is used to input the single line text entry from the user. For multi-line text input, Text widget is used. Output: Frame: It acts as a container to hold the widgets. It is used for grouping and organizing the widgets.
Output: Label : It refers to the display box where you can put any text or image which can be updated any time as per the code. Output: Listbox : It offers a list to the user from which the user can accept any number of options.
Output: MenuButton : It is a part of top-down menu which stays on the window all the time. Every menubutton has its own functionality. Output: Menu : It is used to create all kinds of menus used by the application. There are number of options which are used to change the format of this widget. Output: Message : It refers to the multi-line and non-editable text. It works same as that of Label. Output: RadioButton: It is used to offer multi-choice option to the user. It offers several options to the user and the user has to choose one option.
Output: Scale: It is used to provide a graphical slider that allows to select any value from that scale. Output: Scrollbar : It refers to the slide controller which will be used to implement listed widgets.
Python – Tkinter Entry Widget
Output: Text: To edit a multi-line text and format the way it has to be displayed. There are number of options which are used to change the format of the text. Output: TopLevel: This widget is directly controlled by the window manager.