PYTHON PROGRAM • MODULES, DATES & REGULAR EXPRESSIONS

Find Numbers with a Regular Expression in Python

Learn find numbers with a regular expression in python with a short, executable Python example.

Beginnerrefindall()Regex

PROBLEM UNDERSTANDING

Input and expected output

Sample input

No input required

Sample output

['200', '106', '112']

COMPLETE PYTHON PROGRAM

Complete Python implementation

import re
text = 'C 200, DSA 106, ADS 112'
print(re.findall(r'\d+', text))

CURRENT STEP

Select Start to walk through the important lines.

SELECTED LINE

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EXPECTED OUTPUT FOR THE SAMPLE

['200', '106', '112']

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PROGRAM EXPLANATION

Algorithm and explanation

Import the required standard-library tools and prepare the sample data for find numbers with a regular expression.
Apply re and findall() to compute the required result.
Display the result for find numbers with a regular expression and compare it with the documented sample output.

This example of find numbers with a regular expression computes the result directly from the prepared sample data. It demonstrates re, findall(), and Regex and prints a deterministic result that can be checked against the sample output.

EFFICIENCY

Time and space complexity

Time complexity

O(n)

Auxiliary space

O(n)

DEBUGGING CHECKLIST

Common mistakes

Check this

For find numbers with a regular expression, keep the data shape and value types consistent with re.

Check this

Apply re in the same order shown by the algorithm; changing the order can change the result.

Check this

Verify the final re and findall() result against the sample before trying new data.

Try it yourself

Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.