Master Python Regex: 14 Essential Special Characters Explained

Python Regular Expression Special Characters Overview

Today we share the last special character "\d" of regular expressions, with a detailed tutorial below.

1. \d – digit

The \d character matches any digit. Example shown in the image.

The "+" symbol indicates one or more repetitions; in the example only "4" appears due to greedy mode.

2. ? – non‑greedy (optional) match

To match "2004", add "?" after the pattern, resulting in a non‑greedy match that captures the full number.

3. {n} – exact repetition

Using curly braces you can specify the exact number of digits, e.g., {4} matches a four‑digit number.

Below is a quick recap of common regex special characters:

^ – anchors the start of a string.

* – matches the preceding element zero or more times.

. – matches any character.

$ – anchors the end of a string.

? – makes the preceding token optional (non‑greedy mode).

+ – matches one or more repetitions (excluding zero).

{2}, {2,}, {2,5} – specify exact, minimum, or range repetitions.

| – logical OR between alternatives.

[] , [A-Za-z0-9] , [^] – character classes, ranges, and negation.

\s and \S – match whitespace and non‑whitespace respectively.

\w and \W – match word characters (letters, digits, underscore) and their complement.

[\u4E00-\u9FA5] – matches Chinese characters.

() – captures groups for extraction.

These symbols form the foundation for building powerful pattern matching in Python.