Extract Words from String in Python

Introduction

In Python, a string is a sequence of characters enclosed within single or double quotes. Sometimes, we need to extract individual words from a string. In this challenge, you are tasked with writing a function that takes a string and returns a list of words.

Skills Graph

%%%%{init: {'theme':'neutral'}}%%%% flowchart RL python(("Python")) -.-> python/AdvancedTopicsGroup(["Advanced Topics"]) python(("Python")) -.-> python/BasicConceptsGroup(["Basic Concepts"]) python(("Python")) -.-> python/DataStructuresGroup(["Data Structures"]) python(("Python")) -.-> python/FunctionsGroup(["Functions"]) python(("Python")) -.-> python/ModulesandPackagesGroup(["Modules and Packages"]) python/BasicConceptsGroup -.-> python/comments("Comments") python/DataStructuresGroup -.-> python/lists("Lists") python/DataStructuresGroup -.-> python/tuples("Tuples") python/FunctionsGroup -.-> python/function_definition("Function Definition") python/FunctionsGroup -.-> python/default_arguments("Default Arguments") python/ModulesandPackagesGroup -.-> python/importing_modules("Importing Modules") python/ModulesandPackagesGroup -.-> python/standard_libraries("Common Standard Libraries") python/AdvancedTopicsGroup -.-> python/regular_expressions("Regular Expressions") subgraph Lab Skills python/comments -.-> lab-13743{{"Extract Words from String"}} python/lists -.-> lab-13743{{"Extract Words from String"}} python/tuples -.-> lab-13743{{"Extract Words from String"}} python/function_definition -.-> lab-13743{{"Extract Words from String"}} python/default_arguments -.-> lab-13743{{"Extract Words from String"}} python/importing_modules -.-> lab-13743{{"Extract Words from String"}} python/standard_libraries -.-> lab-13743{{"Extract Words from String"}} python/regular_expressions -.-> lab-13743{{"Extract Words from String"}} end

String to Words

Write a function string_to_words(s: str, pattern: str = '[a-zA-Z-]+') -> List[str] that takes a string s and an optional pattern string as arguments and returns a list of words in the string.

The function should use re.findall() with the supplied pattern to find all matching substrings.
If the pattern argument is not provided, the function should use the default regexp, which matches alphanumeric and hyphens.

import re

def words(s, pattern = '[a-zA-Z-]+'):
  return re.findall(pattern, s)

words('I love Python!!') ## ['I', 'love', 'Python']
words('python, javaScript & coffee') ## ['python', 'javaScript', 'coffee']
words('build -q --out one-item', r'\b[a-zA-Z-]+\b')
## ['build', 'q', 'out', 'one-item']

Summary

In this challenge, you learned how to extract individual words from a string using regular expressions in Python. You can now use this function to split a string into words and perform further operations on them.