Replacing specific words in a string (Python)

Question

I would like to replace words in a string sentence such as:

What $noun$ is $verb$?

What's the regular expression to replace the characters in '$ $' (inclusive) with actual nouns/verbs?

score 20 · Accepted Answer · edited Dec 22 '21 at 06:07

20

You don't need a regular expression for that. I would do

string = "What $noun$ is $verb$?"
print string.replace("$noun$", "the heck")

Only use regular expressions when needed. It's generally slower.

edited Dec 22 '21 at 06:07

Mikhail Lebedev

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answered Sep 21 '12 at 21:15

Ztyx

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Could string the replaces together as well: `str.replace("$noun$", noun).replace("$verb$", verb)` – ernie Sep 21 '12 at 21:20
I have a database of a list of words and the type (Word, type). Type would be noun, verb, etc. I need to check what type of word it is before I replace it. How would you do that? – ono Sep 24 '12 at 14:09
Hm, I'm not sure I follow. What type of database? If the database is small I would load it into memory and store it as a dictionary. Looking up the type would simply be `types[word]`. – Ztyx Sep 24 '12 at 21:11

score 5 · Answer 2 · answered Oct 19 '15 at 08:42

5

Given that you are free to modify $noun$ etc. to your liking, best practise to do this nowadays is probably to using the format function on a string:

"What {noun} is {verb}?".format(noun="XXX", verb="YYY")

answered Oct 19 '15 at 08:42

Ztyx

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score 1 · Answer 3 · answered Sep 21 '12 at 21:13

1

In [1]: import re

In [2]: re.sub('\$noun\$', 'the heck', 'What $noun$ is $verb$?')
Out[2]: 'What the heck is $verb$?'

answered Sep 21 '12 at 21:13

Roland Smith

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score 1 · Answer 4 · answered Jul 02 '21 at 20:09

use a dictionary to hold the regular expression pattern and value. use the re.sub to replace the tokens.

dict = {
   "(\$noun\$)" : "ABC",
   "(\$verb\$)": "DEF"
} 
new_str=str
for key,value in dict.items():
   new_str=(re.sub(key, value, new_str))
print(new_str)

output:

What ABC is DEF?

Replacing specific words in a string (Python)

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