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InputFilter

Prevents the insertion of characters matching (or not matching) a particular pattern(regex_string), by replacing the characters with the given replacement_string.

InputFilter class takes 3 parameters:

allow​

A boolean value indicating whether to allow or deny/block the matched patterns.

Value is of type bool and defaults to True.

case_sensitive​

Whether this regular expression is case sensitive.

If the regular expression is not case sensitive, it will match an input letter with a pattern letter even if the two letters are different case versions of the same letter.

dot_all​

Whether "." in this regular expression matches line terminators.

When false, the "." character matches a single character, unless that character terminates a line. When true, then the "." character will match any single character including line terminators.

This feature is distinct from multiline. They affect the behavior of different pattern characters, so they can be used together or separately.

multiline​

Whether this regular expression matches multiple lines.

If the regexp does match multiple lines, the "^" and "$" characters match the beginning and end of lines. If not, the characters match the beginning and end of the input.

regex_string​

A regular expression pattern for the filter.

It is recommended to use raw strings (prefix your string with r) for the pattern, ex: r"pattern".

replacement_string​

A string used to replace banned/denied patterns. Defaults to an empty string.

unicode​

Whether this regular expression uses Unicode mode.

Predefined input filters​

NumbersOnlyInputFilter()​

Allows only numbers.

TextOnlyInputFilter()​

Allows only text.

Usage example​

ft.CupertinoTextField(
    placeholder_text="Only numbers are allowed",
    input_filter=ft.InputFilter(allow=True, regex_string=r"^[0-9]*$", replacement_string="")
)
ft.TextField(
    label="Only letters are allowed",
    input_filter=ft.TextOnlyInputFilter()
)