Python re.sub() Method
Python re Modulere.sub()is Pythonremodule function forreplacing matched items.
It finds all matching substrings in the string and replaces them with the specified content.
Word Meaning： subis the abbreviation for substitute (replace).
Basic Syntax and Parameters
Syntax Format
re.sub(pattern, repl, string, count=0, flags=0)
Parameter Description
- pattern: the regular expression to match
- repl: the replacement text, which can be a string or a function
- string: the original string
- count: the maximum number of replacements; 0 means replace all
- flags: regular expression flags
Function Description
- Return Value: Returns the new string after replacement.
Examples
Example 1: Basic Replacement
Example
import re
text = "Python is good, Python is great"
# Replace Python with Java
result = re.sub(r'Python', 'Java', text)
print(result)
text = "Python is good, Python is great"
# Replace Python with Java
result = re.sub(r'Python', 'Java', text)
print(result)
Expected output:
Java is good, Java is great
Example 2: Replace a Specified Number of Times
Example
import re
text = "Python is good, Python is great"
# Replace only the first one
result = re.sub(r'Python', 'Java', text, count=1)
print(result)
text = "Python is good, Python is great"
# Replace only the first one
result = re.sub(r'Python', 'Java', text, count=1)
print(result)
Expected output:
Java is good, Python is great
Example 3: Replace Using Regular Expression
Example
import re
text = "My phone number is 138-1234-5678"
# Replace the middle 4 digits of the phone number with ****
result = re.sub(r'\d{4}', '****', text)
print(result)
text = "My phone number is 138-1234-5678"
# Replace the middle 4 digits of the phone number with ****
result = re.sub(r'\d{4}', '****', text)
print(result)
Expected output:
我的手机号是 138-****-5678
Example 4: Using Group References
Example
import re
text = "2024-04-02"
# Swap the order of year, month, and day
result = re.sub(r'(\d{4})-(\d{2})-(\d{2})', r'\3/\2/\1', text)
print(result)
text = "2024-04-02"
# Swap the order of year, month, and day
result = re.sub(r'(\d{4})-(\d{2})-(\d{2})', r'\3/\2/\1', text)
print(result)
Expected output:
02/04/2024
Example 5: Using a Function as Replacement Content
Example
import re
text = "3 apples, 5 bananas, 8 oranges"
# Replace numbers with number + 1
def add_one(match):
return str(int(match.group()) + 1)
result = re.sub(r'\d+', add_one, text)
print(result)
text = "3 apples, 5 bananas, 8 oranges"
# Replace numbers with number + 1
def add_one(match):
return str(int(match.group()) + 1)
result = re.sub(r'\d+', add_one, text)
print(result)
Expected output:
苹果4个，香蕉6个，橙子9个
Other Extensions