Python – Program that matches a word containing ‘g’ followed by one or more e’s using regex

Regular expressions (regex) in Python provide powerful pattern matching capabilities. In this tutorial, we'll learn how to match words containing 'g' followed by one or more 'e' characters using different regex methods.

Understanding the Regex Pattern

The pattern r'\bge+\w*\b' breaks down as follows ?

• \b Word boundary to match complete words

• g Literal character 'g'

• e+ One or more 'e' characters

• \w* Zero or more word characters (optional)

• \b Word boundary at the end

Method 1: Using findall() Function

The findall() method returns all non-overlapping matches as a list ?

import re

# Sample text with words containing 'g' followed by 'e'
text = "green geese gather energy in the garden"

# Pattern to match 'g' followed by one or more 'e'
pattern = r'\bge+\w*\b'

# Find all matches
matches = re.findall(pattern, text)
print("Matches found:", matches)

Matches found: ['green', 'geese']

Method 2: Using finditer() Function

The finditer() method returns an iterator of match objects with additional information ?

import re

text = "green geese gather energy in the garden"
pattern = r'\bge+\w*\b'

# Find all matches with positions
matches = re.finditer(pattern, text)

for match in matches:
    print(f"Match: '{match.group()}' at position {match.start()}-{match.end()}")

Match: 'green' at position 0-5
Match: 'geese' at position 6-11

Method 3: Using search() Function

The search() method finds the first occurrence of the pattern ?

import re

text = "The green geese are beautiful"
pattern = r'\bge+\w*\b'

# Find first match
first_match = re.search(pattern, text)

if first_match:
    print(f"First match: '{first_match.group()}' at position {first_match.start()}")
else:
    print("No match found")

First match: 'green' at position 4

Complete Example with Multiple Patterns

import re

def find_g_e_words(text):
    """Find words starting with 'g' followed by one or more 'e' characters"""
    pattern = r'\bge+\w*\b'
    matches = re.findall(pattern, text, re.IGNORECASE)
    return matches

# Test with different texts
test_texts = [
    "The green geese flew over the gentle breeze",
    "Geography and geometry are interesting subjects", 
    "Glee and geek are common words"
]

for i, text in enumerate(test_texts, 1):
    matches = find_g_e_words(text)
    print(f"Text {i}: {text}")
    print(f"Matches: {matches}")
    print()

Text 1: The green geese flew over the gentle breeze
Matches: ['green', 'geese', 'gentle']

Text 2: Geography and geometry are interesting subjects
Matches: ['Geography', 'geometry']

Text 3: Glee and geek are common words
Matches: ['Glee', 'geek']

Comparison of Methods

Conclusion

Python's re module provides multiple methods to match patterns like 'g' followed by 'e' characters. Use findall() for simple string results, finditer() when you need position information, and search() for the first match only.