What will you learn?

In this tutorial, you will master the art of using regular expressions in Python to extract numeric values from strings. You will learn how to efficiently retrieve numbers based on specific identifying expressions using regex.

Introduction to the Problem and Solution

When faced with the task of extracting numerical values from strings based on certain identifying patterns, regular expressions serve as a valuable tool. By harnessing the capabilities of regex in Python, you can easily and effectively extract numeric data from text.

Let’s delve into the solution below:


import re

# Sample string containing numbers after an identifying expression
sample_string = "The price is $25.99 for product A, $15.50 for product B, and $100 for product C"

# Using regular expression to extract numeric values following '$'
numbers_list = re.findall(r'\$(\d+\.\d+|\d+)', sample_string)

print(numbers_list)  # Output: ['25.99', '15.50', '100']

# Copyright PHD

Note: For more detailed insights into regular expressions in Python, visit our website PythonHelpDesk.com.


In the provided code snippet: – We import the re module which provides support for working with regular expressions. – Define a sample string that contains numerical values following an identifying expression (‘$’ symbol). – Utilize re.findall() method with a regex pattern \$(\d+\.\d+|\d+) that captures either decimal numbers or integers preceded by ‘$’. – The extracted numerical values are stored in numbers_list.

    How do I install the re module in Python?

    The re module comes built-in with Python, so there is no separate installation required to use regular expressions.

    Can I extract multiple sets of numbers using regex?

    Yes, you can define multiple capturing groups within your regex pattern to extract various sets of numbers from a string.

    What if my numeric value includes commas or other symbols?

    You can modify your regex pattern accordingly to accommodate different formats of numeric values such as commas or currency symbols.

    Is there any online tool available for testing and building regex patterns?

    Websites like RegExr or Regex101 provide interactive platforms where you can test your regex patterns against sample text inputs.

    Can I apply modifiers like case insensitivity while using regex?

    Certainly! Specify flags like re.IGNORECASE when compiling your regex pattern for case-insensitive matching.

    How do I handle whitespace characters while matching patterns using regex?

    Manage whitespace characters by including \s* within your pattern which accounts for zero or more whitespace occurrences at that position.


    Mastering regular expressions empowers you to efficiently manipulate and extract data based on defined patterns in Python. Enhance your ability to work with textual data effectively by honing this skillset.

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