python-regexHow to match a question mark in Python regex?

To match a question mark in Python regex, use the ? character. This character is used to indicate that the preceding character is optional. For example, the following code will match strings that contain either one or two question marks:

import re

pattern = r"\?\??"

test_string = "This string contains one question mark?"

match = re.search(pattern, test_string)

if match:
    print("Match found!")
else:
    print("No match found!")

Output example

Match found!

The code consists of the following parts:

• import re: This imports the re module, which provides functions for working with regular expressions.
• pattern = r"\?\??": This defines the regular expression pattern. The r prefix indicates that the string is a raw string, which means that backslashes are not treated as escape characters. The ? character is used to indicate that the preceding character is optional. In this case, the pattern will match strings that contain either one or two question marks.
• test_string = "This string contains one question mark?": This defines the string that will be tested against the regular expression pattern.
• match = re.search(pattern, test_string): This uses the re.search() function to search for a match between the regular expression pattern and the test string.
• if match:: This checks if a match was found.
• print("Match found!"): This prints a message if a match was found.
• print("No match found!"): This prints a message if no match was found.

For more information about regular expressions in Python, see the Python documentation.

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