re.sub() (docs for Python 2 and Python 3) does replace all matches it finds, but your use of .* may have caused the regex to match too much (even other occurences of .00. etc.). Simply do:
In [2]: re.sub(r"\.(00|11)\.", r"X\1X", ".00..0..11.")
Out[2]: 'X00X.0.X11X'
Note that patterns cannot overlap:
In [3]: re.sub(r"\.(00|11)\.", r"X\1X", ".00.11.")
Out[3]: 'X00X11.'
Python documentation
docs.python.org › 3 › library › re.html
re — Regular expression operations — Python 3.14.3 ...
sub() replaces every occurrence of a pattern with a string or the result of a function. This example demonstrates using sub() with a function to “munge” text, or randomize the order of all the characters in each word of a sentence except ...
Videos
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PYnative
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Python Regex Replace and Replace All – re.sub()
July 19, 2021 - Let’s assume you have the following string and you wanted to replace all the whitespace with an underscore. target_string = "Jessa knows testing and machine learning" ... import re target_str = "Jessa knows testing and machine learning" res_str = re.sub(r"\s", "_", target_str) # String after replacement print(res_str) # Output 'Jessa_knows_testing_and_machine_learning'Code language: Python (python) Run
Spark By {Examples}
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Python regex replace all - Spark By {Examples}
May 31, 2024 - One of the most used methods in the Python re library is the re.sub() which is used to replace a new string for all instances of a pattern in a string (Python regex replaces all).
Note.nkmk.me
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Replace Strings in Python: replace(), translate(), and Regex | note.nkmk.me
May 4, 2025 - If you need to replace substrings based on regex patterns, use the sub() or subn() functions from the re module. re.sub() — Regular expression operations — Python 3.13.3 documentation
Educative
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What is the re.sub() function in Python?
The re module provides users with ... the re module functions. It is a substitution function that replaces all occurrences of the specified pattern with a new string....
LZone
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Python re.sub Examples
result = re.sub('abc', '', input) # Delete pattern abc result = re.sub('abc', 'def', input) # Replace pattern abc -> def result = re.sub(r'\s+', ' ', input) # Eliminate duplicate whitespaces using wildcards result = re.sub('abc(def)ghi', r'\1', input) # Replace a string with a part of itself
GeeksforGeeks
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re.sub() - Python RegEx - GeeksforGeeks
July 23, 2025 - re.sub() method in Python parts of a string that match a given regular expression pattern with a new substring. This method provides a powerful way to modify strings by replacing specific patterns, which is useful in many real-life tasks like text processing or data cleaning. ... import re a = "apple orange apple banana" pattern = "apple" repl = "grape" # Replace all occurrences of "apple" with "grape" result = re.sub(pattern, repl, a) print(result)
Python.org
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Replacement argument in re.sub() - Python Help - Discussions on Python.org
November 10, 2022 - Hello, I have the following strings that I would like to match and replace. I am able to match the strings but struggling to carry out a replacement - the output either doesn’t change or it completely erases sections of the input string. i have included an example of one of many options I have tried. scenario 1: input string: (BXXADDB)(BXXXCAC1)(CXX2A)CANEVER desired output string: (BXXADDB)(BXXXCAC1)(CXX2A)*CANEVER pattern = r"^\([A-Za-z0-9]+\)\([A-Za-z0-9]+\)\([^)]*\)[a-zA-Z]+$" replaceme...
Codecademy
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Python | Regular Expressions | re.sub() | Codecademy
October 14, 2024 - The re.sub() function replaces matching substrings with a new string for all occurrences, or a specified number. ... Looking for an introduction to the theory behind programming? Master Python while learning data structures, algorithms, and more!
Medium
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Complete Python Regex Replace Guide using re.sub() | PyPixel | by Stilest | Medium
December 8, 2023 - The re.sub() method in Python provides powerful search and replace functionality using regular expressions. The regex replace works by specifying the string to modify, defining a regex pattern to match against, and providing a replacement substring.
Python Tutorial
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Python Regex sub() Function
December 10, 2021 - Besides a regular expression, the pattern can be Pattern object. ... count parameter specifies the maximum number of matches that the sub() function should replace. If you pass zero to the count parameter or completely skip it, the sub() function will replace all the matches.
DEV Community
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Python: differences between `.replace()` and `.re.sub()` methods - DEV Community
July 30, 2024 - Example: re.sub(r'\bworld\b', 'Python', 'hello world') results in 'hello Python'. ... Only supports simple string matching. Cannot use regular expressions or complex patterns. Replaces all occurrences of the substring if count is not specified.
Flexiple
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Python regex: How to search and replace strings | Flexiple - Flexiple
import re str = "Joe-Kim Ema Max Aby Liza" print(re.sub("(\s)|(-)", ", ", str)) ... If you want to replace multiple patterns with different replacements, regex can be used.
Finxter
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Python Regex re.sub() - Be on the Right Side of Change
June 13, 2023 - The re.sub(pattern, repl, string, count=0, flags=0) method returns a new string where all occurrences of the pattern in the old string are replaced by repl. Read more in our blog tutorial.
Python Examples
pythonexamples.org › python-re-sub
Python re.sub() - Replace using Regular Expression
In this tutorial of Python Examples, we learned how to use re.sub() function to replace or substitute all the matchings for a given pattern in a string with the replacement string, with the help of example programs.
Squash
squash.io › replacing-strings-in-python-using-re-sub
How to Replace Strings in Python using re.sub
Substitutions ... The function takes a pattern that it looks for in the provided string. Once located, it replaces the pattern with the repl argument. The count argument defines how many occurrences of the pattern are replaced, with the default being all occurrences (0). The flags argument can modify the pattern matching, for instance making it case-insensitive. Related Article: How to Use Python's Numpy.Linalg.Norm Function
Top answer 1 of 4
12
The two substitutions you'd want in your example overlap - the comma between your two instances of 't' will be matched by (.) in the first case, so ([^']) in the second case never gets a chance to match it. This slightly modified version might help:
line = re.sub(r"(?<!')'t'(?=.)", r"THIS_IS_TRUE", line)
This version uses lookahead and lookbehind syntax, described here.
2 of 4
3
How about
line = line.replace("'t'", "THIS_IS_TRUE").replace("'f'", "THIS_IS_FALSE")
without using re. This replaces all occurrences of 't' and 'f'. Just make sure that no car is named t.
Top answer 1 of 4
49
You can replace it directly:
>>> import re
>>> s = 'sdfjoiweng%@$foo$fsoifjoi'
>>> print(re.sub('foo','bar',s))
sdfjoiweng%@$bar$fsoifjoi
It will also work for more occurrences of foo like below:
>>> s = 'sdfjoiweng%@$foo$fsoifoojoi'
>>> print(re.sub('foo','bar',s))
sdfjoiweng%@$bar$fsoibarjoi
If you want to replace only the 1st occurrence of foo and not all the foo occurrences in the string then alecxe's answer does exactly that.
2 of 4
7
re.sub(r'\bfoo\b', 'bar', s)
Here, the \b defines the word boundaries - positions between a word character (\w) and a non-word character - exactly what you have matching for foo inside the sdfjoiweng%@$foo$fsoifjoi string. Works for me:
In [1]: import re
In [2]: s = 'sdfjoiweng%@$foo$fsoifjoi'
In [3]: re.sub(r'\bfoo\b', 'bar', s)
Out[3]: 'sdfjoiweng%@$bar$fsoifjoi'