Remove multiple substring from a string Python

Question

I want to replace multiple substrings in a single string, and I want to know what approach is most efficient / best practice.

I've tried using str.replace() and it works but that seems inefficient. I'm running Python 3.6, so I'd like a solution compatible with that.

For some context here, I want to create the name of a (new) class from some text I read. So I need to convert text to (strings for) valid Python identifiers (e.g., "bad-Classname's" becomes "badClassnames"). So while my question of the best way to replace multiple substrings in a single string still stands, if there is a better way to convert text to class names I'd be happy to hear that too.

My existing code is as follows:

my_str = my_str.replace(" ", "").replace(",", "").replace("/", "").replace("'", "").replace("-", "").replace("’", "")

Is there a better way to do this? Regular expressions, a for loop, some builtin string method that I didn't know about?

RomanPerekhrest · Accepted Answer · 2019-10-19 07:16:44Z

2

Shortly with regexp substitution:

import re

my_str = "bad-Classname's"
my_str = re.sub(r"[ ,/'’-]", "", my_str)
print(my_str)   # badClassnames

[ ,/'’-] - regex character class, matches a single character in the list ",/'’-"

answered Oct 19, 2019 at 7:16

RomanPerekhrest

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stovfl · Accepted Answer · 2019-10-19 08:17:04Z

2

use str.translate()

# this line builds the translation table
# and can be done once
table = str.maketrans({c:'' for c in " ,/'-’"})

my_str = "bad-Classname's"

# this line does the replacement
my_str = my_str.translate(table)

print(my_str)   
# >>> badClassnames

edited Oct 19, 2019 at 8:17

stovfl

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answered Oct 19, 2019 at 7:32

RootTwo

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Soumya Ranjan Swain · Accepted Answer · 2019-10-19 07:19:37Z

0

You can use something like this:

string = 'this is a test string'
items_to_remove = ['this', 'is', 'a', 'string']

In [1]: [x for x in string.split() if x not in {'is', 'this', 'a', 'string'}]
Out[1]: ['test']

Hope this answers your query.

answered Oct 19, 2019 at 7:19

Soumya Ranjan Swain

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Remove multiple substring from a string Python

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use str.translate()

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use str.translate()

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