Python re.sub()

The re.sub() function replaces matching substrings with a new string for all occurrences, or a specified number.

Syntax

re.sub(<pattern>, <replacement>, string, <count>, <flags>)

• <pattern>: A regular expression pattern used to match substrings.
  • A string: Jane Smith
  • Character class codes: /w, /s, /d
  • Regex symbols: $, |, ^
• <replacement>: The replacement argument. This can either be a string or a function.
• <count>: An integer specifying the number of occurrences to replace. The default is to replace all matches.
• <flags>: Specifies additional options such as IGNORECASE, VERBOSE, DOTALL, etc.

Example

The following example replaces all occurrences of “BI” with “business intelligence”:

import re

def replace_business_intelligence(match):
  return 'business intelligence'

blurb = '''The analytics firm uses a range of BI tools to visualize data. Their internal data science team suggests
bi tools may be their most valuable resource.'''

# Use the function `replace_bussines_intelligence` as the replacement argument in re.sub()
match = re.sub(r'bi', replace_business_intelligence, blurb, flags=re.IGNORECASE)

print(match)

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This will print the following where “bi” is replaced with “business intelligence”:

The analytics firm uses a range of business intelligence tools to  visualize data. Their internal data science team suggests
business intelligence tools may be their most valuable resource.

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Codebyte Example

Replace all numerical values with “REDACTED”:

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