Python - Replace only exact word in string

Question

I want to replace only specific word in one string. However, some other words have that word inside but I don't want them to be changed.

For example, for the below string I only want to replace x with y in z string. how to do that?

x = "the"
y = "a"
z = "This is the thermometer"

I suggest using `.split()` to convert your string into a list of words, then replacing the word that equals your keyword, then rebuilding the string from the list. — Błotosmętek, Feb 15 '20 at 09:37
what if I have string with 10k words. then it wouldn't be efficient :/ — Anisa Kollenhag, Feb 15 '20 at 09:38
@MichaelO.this will not work in general case - test for `x = 'is'` — Błotosmętek, Feb 15 '20 at 09:38
Alternative is to use regular expressions, which is not very efficient either. You should test for yourself which method suits you more. — Błotosmętek, Feb 15 '20 at 09:41
thanks for the help. what if a word was like this. "this is 114-221 #114-221" and i only want to replace first 114-221 but not second one? @Błotosmętek — Anisa Kollenhag, Feb 15 '20 at 10:11
For the solution using split: it will work without change; for Austin's solution you need to add `count=1` to re.sub parameters. — Błotosmętek, Feb 15 '20 at 13:12

score 1 · Answer 1 · answered Feb 15 '20 at 09:47

1

import re

pattern=r'\bthe\b' # \b - start and end of the  word
repl='a'
string = 'This is the thermometer'

string=re.sub(pattern, repl, string)

answered Feb 15 '20 at 09:47

n1tr0xs

thanks for the help. what if a word was like this. "this is 114-221 #114-221" and i only want to replace first 114-221 but not second one? – Anisa Kollenhag Feb 15 '20 at 10:26

score 0 · Answer 2 · answered Feb 15 '20 at 09:49

0

In your case you can use re.sub(x, y, z). You can read the documentation here for more information.

answered Feb 15 '20 at 09:49

Kurosh Ghanizadeh

2 Answers2