Tkinter filedialog asksaveasfilename: Save Files In Python

In this tutorial, you’ll learn several aspects of filedialog asksaveasfilename function in Tkinter, including its syntax, parameters, how to set default values, implement file filters, and execute callback functions after file selection.



Syntax and Parameters

Let’s start with the basic syntax of asksaveasfilename:

from tkinter import filedialog
filename = filedialog.asksaveasfilename()



In this example, once a file is selected or a filename is entered, the full path to that file is returned.

initialdir: This parameter sets the directory that the dialog box initially displays.

filename = filedialog.asksaveasfilename(initialdir='/')

The dialog is opened in the root directory (/), facilitating a user-friendly navigation experience from a common starting point.

filetypes: This parameter specifies the file types shown in the dialog.

filename = filedialog.asksaveasfilename(filetypes=[('Text Files', '*.txt'), ('All Files', '*.*')])

It restricts the file types to text files and all files, simplifying the process for users to locate and select the desired file format.

defaultextension: This parameter automatically appends a specified file extension if the user doesn’t include one.

filename = filedialog.asksaveasfilename(defaultextension='.txt')

When the user omits the file extension, .txt is used by default.

confirmoverwrite: This parameter prompts the user to confirm before overwriting an existing file.

filename = filedialog.asksaveasfilename(confirmoverwrite=True)

It activates a confirmation dialog if the file already exists.


Return Value

When a user successfully selects a file and clicks “Save” in the dialog, asksaveasfilename returns the absolute path to the chosen file as a string.

If the user cancels the operation, it returns an empty string.

from tkinter import filedialog, Tk
root = Tk()
filename = filedialog.asksaveasfilename(initialdir="/", title="Select file", 
                                        filetypes=(("text files", "*.txt"), ("all files", "*.*")))
print("Selected file:", filename)

Case 1: File Selected

Output when a file is selected:

Selected file: /path/to/selected/file.txt

Here, the user chose a file, and the function returned the full path to that file.

Case 2: Operation Cancelled

Output when cancel is clicked:

Selected file:

In this case, the user cancelled the operation and it returns an empty string.


Custom File Filters

To set up file filters, you use the filetypes parameter. This parameter accepts a list of tuples, each representing a file type.

The first element of the tuple is a descriptive string, and the second is the file extension pattern.

from tkinter import filedialog
filename = filedialog.asksaveasfilename(filetypes=[("Text files", "*.txt"), ("Python files", "*.py")])



In this example, the dialog box now only shows files that are either text files (*.txt) or Python script files (*.py).

You can also add a filter for all files:

filename = filedialog.asksaveasfilename(filetypes=[("Text files", "*.txt"), ("Python files", "*.py"), ("All files", "*.*")])



Users now can view and save files of any type.


Setting Default Filename

The initialfile parameter is used to specify a default filename that appears in the filename field when the dialog opens.

It suggests a standard naming format when you’re saving a new version of an existing file.

from tkinter import filedialog
filename = filedialog.asksaveasfilename(initialfile="Untitled.txt")



In this code, the file dialog opens with “Untitled.txt” pre-filled in the filename field.

You can combine initialfile with file filters for a more refined experience:

filename = filedialog.asksaveasfilename(initialfile="Untitled.txt", filetypes=[("Text files", "*.txt")])



In this case, not only is “Untitled.txt” pre-filled, but the file type is also restricted to text files.


Execute a function after file selection (Callback Function)

A callback function allows you to execute specific actions right after a file is selected or saved.

Let’s save user preferences to a file once it’s selected:

from tkinter import filedialog
def save_preferences(file_path):
    if file_path:
        print(f"Saving preferences to {file_path}")
        # Code to save preferences goes here
        print("File save operation cancelled.")
filename = filedialog.asksaveasfilename()

Output if a file is selected:

Saving preferences to /path/to/selected/file.txt

Output if the operation is cancelled:

File save operation cancelled.
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