string replace() function perfectly solves this problem:
string.replace(s, old, new[, maxreplace])
Return a copy of string s with all occurrences of substring old replaced by new. If the optional argument maxreplace is given, the first maxreplace occurrences are replaced.
>>> u'longlongTESTstringTEST'.replace('TEST', '?', 1)
u'longlong?stringTEST'
Top answer 1 of 2
379
string replace() function perfectly solves this problem:
string.replace(s, old, new[, maxreplace])
Return a copy of string s with all occurrences of substring old replaced by new. If the optional argument maxreplace is given, the first maxreplace occurrences are replaced.
>>> u'longlongTESTstringTEST'.replace('TEST', '?', 1)
u'longlong?stringTEST'
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27
Use re.sub directly, this allows you to specify a count:
regex.sub('', url, 1)
(Note that the order of arguments is replacement, original not the opposite, as might be suspected.)
StudyMite
studymite.com › python › find-and-replace-first-occurrence-of-a-string-in-python
Find and Replace First Occurrence Of a String in python | StudyMite
March 2, 2023 - The find() method returns the index of the first occurrence of the specified word or phrase, or -1 if it is not found. This approach is useful when you want to replace a specific word or phrase, but you don't want to use the replace() method, ...
python - Replace first occurrence only of a string? - Stack Overflow
Copy>>> help(str.replace) Help ... copy of string S with all occurrences of substring old replaced by new. If the optional argument count is given, only the first count occurrences are replaced. ... Sign up to request clarification or add additional context in comments. ... Save this answer. ... Show activity on this post. ... The third parameter is the maximum number of occurrences that you want to replace. From the documentation for Python... More on stackoverflow.com
regex - How to replace the first occurrence of a regular expression in Python? - Stack Overflow
I want to replace just the first occurrence of a regular expression in a string. Is there a convenient way to do this? More on stackoverflow.com
python - How can I replace the first occurrence of a character in every word? - Stack Overflow
How can I replace the first occurrence of a character in every word? Say I have this string: hello @jon i am @@here or @@@there and want some@thing in '@here" # ^ ^^ ^^^ ... More on stackoverflow.com
Pattern to match first occurrence in line?
The easiest would be to match from the beginning of the line lazily: ^.\{-}foo This will stop at the first occurrence of foo. To skip the leading stuff and just keep foo itself as the match, use \zs: ^.\{-}\zsfoo If the search needs to be more robust, use a negative look-behind. Warning: The syntax will make your eyes bleed. ^\(\(foo\)\@ More on reddit.com
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May 20, 201201:23
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Python - Replace first Occurrence Only In a List - YouTube
Medium
parvez1487.medium.com › find-and-replace-first-occurrence-of-a-string-in-python-pythonpip-com-432fafdd21aa
Find and Replace First Occurrence of a String in Python — pythonpip.com | by Parvez Alam | Medium
January 7, 2024 - The replace() method is a commonly used way to find and replace a string in Python. by default, replaces() method finds and replaces all occurrences of a string. You can use concatenation and slicing to replace only the first occurrence.
W3Schools
w3schools.com › python › ref_string_replace.asp
Python String replace() Method
The replace() method replaces a specified phrase with another specified phrase. Note: All occurrences of the specified phrase will be replaced, if nothing else is specified. ... txt = "one one was a race horse, two two was one too." x = ...
ItSolutionstuff
itsolutionstuff.com › post › python-replace-first-occurrence-in-string-exampleexample.html
Python Replace First Occurrence in String Example - ItSolutionstuff.com
October 30, 2023 - In this examples, i will add myString variable with hello string. Then we will use replace() function to replace first occurrence from string in python.
All About AI-ML
indhumathychelliah.com › 2020 › 12 › 20 › different-ways-to-replace-occurences-of-a-substring-in-python-strings
Different Ways to Replace Occurences of a Substring in Python Strings – All About AI-ML
January 2, 2022 - By using the above-mentioned methods, let’s see how to replace substrings in strings. ... s1="one apple,two orange,two banana" s2=s1.replace("two","one") print (s2) #Output:one apple,one orange,one banana · By default, str.replace() will replace all occurrences of “two” by “one” · Example 1: Replace substring “two” by “one” for first occurrence only.
Python Examples
pythonexamples.org › python-string-replace-first-occurrence
Python String - Replace first occurrence
To replace only the first occurrence in a string in Python, you can use string replace() method. Pass the old and new strings as first and second arguments, and pass 1 for count parameter as third argument to replace only one occurrence.
Reddit
reddit.com › r/pythonlearning › find and replace first occurrence of a string in python - pythonpip.com
r/PythonLearning on Reddit: Find and Replace First Occurrence of a String in Python - pythonpip.com
January 7, 2024 - Everything about learning the programming language Python. ... A subreddit for all questions related to programming in any language.
Bobby Hadz
bobbyhadz.com › blog › python-replace-first-character-in-string
Replace First or First N characters in a String in Python | bobbyhadz
Use string slicing to replace the first character in a string, e.g. `new_str = 'new' + my_str[1:]`.
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186
text = text.replace("very", "not very", 1)
>>> help(str.replace)
Help on method_descriptor:
replace(...)
S.replace (old, new[, count]) -> string
Return a copy of string S with all occurrences of substring
old replaced by new. If the optional argument count is
given, only the first count occurrences are replaced.
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64
text = text.replace("very", "not very", 1)
The third parameter is the maximum number of occurrences that you want to replace.
From the documentation for Python:
string.replace(s, old, new[, maxreplace])
Return a copy of string s with all occurrences of substring old replaced by new. If the optional argument maxreplace is given, the first maxreplace occurrences are replaced.
GeeksforGeeks
geeksforgeeks.org › python-replace-occurrences-by-k-except-first-character
Python – Replace occurrences by K except first character | GeeksforGeeks
April 18, 2023 - If the character is equal to the first character and it is not the first occurrence, then replace it with the new character K, else keep the original character. Also, add the first character of the input string as it is in the beginning.
Loekvandenouweland
loekvandenouweland.com › content › replace-only-first-occurrence-in-a-string-in-python.html
Replace only the first phrase occurrence in a Python string.
You have seen the replace function in Python. It takes two arguments: oldphrase and newphrase: ... The method operates on string a and replaces all occurrences of a/ with empty string "". ... To replace the first occurrence only, add a third argument (count) with value 1.
codestudy
codestudy.net › blog › replace-first-occurrence-of-string-in-python
How to Replace the First Occurrence of a String in Python Using Regex — codestudy.net
Examples of Regex Patterns for First Occurrence Replacement ... Before diving into regex, let’s clarify what "first occurrence" means. The "first occurrence" is the earliest substring (or pattern) in a string that matches your target. For example, in "I ate an apple, and the apple was red", the first occurrence of "apple" is the one after "an". Why use regex for this? While Python’s built-in str.replace() can replace the first occurrence of a literal substring, regex allows you to match complex patterns (e.g., numbers, email addresses, or dynamic sequences) that simple string methods can’t handle.
Top answer 1 of 2
79
re.sub() has a count parameter that indicates how many substitutions to perform. You can just set that to 1:
>>> s = "foo foo foofoo foo"
>>> re.sub("foo", "bar", s, 1)
'bar foo foofoo foo'
>>> s = "baz baz foo baz foo baz"
>>> re.sub("foo", "bar", s, 1)
'baz baz bar baz foo baz'
Edit: And a version with a compiled SRE object:
>>> s = "baz baz foo baz foo baz"
>>> r = re.compile("foo")
>>> r.sub("bar", s, 1)
'baz baz bar baz foo baz'
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Specify the count argument in re.sub(pattern, repl, string[, count, flags])
The optional argument count is the maximum number of pattern occurrences to be replaced; count must be a non-negative integer. If omitted or zero, all occurrences will be replaced.
Top answer 1 of 6
50
I would do a regex replacement on the following pattern:
@(@*)
And then just replace with the first capture group, which is all continous @ symbols, minus one.
This should capture every @ occurring at the start of each word, be that word at the beginning, middle, or end of the string.
inp = "hello @jon i am @@here or @@@there and want some@thing in '@here"
out = re.sub(r"@(@*)", '\\1', inp)
print(out)
This prints:
hello jon i am @here or @@there and want something in 'here
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How about using replace('@', '', 1) in a generator expression?
string = 'hello @jon i am @@here or @@@there and want some@thing in "@here"'
result = ' '.join(s.replace('@', '', 1) for s in string.split(' '))
# output: hello jon i am @here or @@there and want something in "here"
The int value of 1 is the optional count argument.
str.replace(old, new[, count])
Return a copy of the string with all occurrences of substring old replaced by new. If the optional argument count is given, only the first count occurrences are replaced.
DevGenius
blog.devgenius.io › different-ways-to-replace-occurences-of-a-substring-in-python-strings-2911b1f7bf86
Different Ways to Replace Occurences of a Substring in Python Strings | by Indhumathy Chelliah | Dev Genius
September 2, 2021 - By using the above-mentioned methods, let’s see how to replace substrings in strings. ... s1="one apple,two orange,two banana" s2=s1.replace("two","one") print (s2) #Output:one apple,one orange,one banana · By default, str.replace() will replace all occurrences of “two” by “one” · Example 1: Replace substring “two” by “one” for first occurrence only.
Iditect
iditect.com › faq › python › replace-first-occurrence-of-string-in-python.html
Replace first occurrence of string in Python
# Define a string my_string = "hello world hello universe" # Replace first occurrence of 'hello' with 'hi' my_string = my_string.replace('hello', 'hi', 1) "Python replace first occurrence of character in string" Description: Users might seek ways to replace the first occurrence of a specific character in a string, which can be done using string manipulation techniques.
sqlpey
sqlpey.com › python › replace-first-occurrence-of-a-string
How to Replace the First Occurrence of a String in Python - …
November 23, 2024 - ... In this case, we want to replace only the first occurrence of “very” with “not very”. Here’s how we can achieve that: You can leverage the replace method in Python which allows an optional count argument to specify how many occurrences to replace.