替换字符串的一部分（如果存在于列表中）（Python）

Question

I want to replace part of the string to blank if present in a list.

For example :

List

foo = ['.com', '.net', '.co', '.in']

Convert these strings to

google.com   
google.co.in 
google.net   
google.com/gmail/   

These strings

google  
google  
google  
google/gmail/

So far i have found this solution. Is there any other optimized way to do it?
replace item in a string if it matches an item in the list

Answer 1

Similar to George Shulkin's answer.

import re
suffixes = ['.com', '.co', '.in', '.net']
patterns = [re.compile(suffix) for suffix in suffixes]

def remove_suffixes(s: str) -> str:
    for pattern in patterns:
        s = pattern.sub("", s)
    return s

# urls = ["google.com", ...
clean_urls = map(remove_suffixes, urls)
# or clean_urls = [remove_suffixes(url) for url in urls]

You might want to use the list comprehension, because it can be faster than map in many cases.

This has the advantage of also compiling the regexes, which can be better for performance when used in a loop.

Or if you decided to use functools.reduce ,

from functools import reduce

def remove_suffixes(s: str) -> str:
    return reduce(lambda s, pattern: pattern.sub("", s), patterns, s) 

Answer 2

You need to split this task in two:

1. Write a code to replace string with a new string if matched.
2. Apply this function to the list.

First can be done with regexp (see below). Second can be done by using map function.

Example of the code to replace substring:

>>> import re
>>> re.sub(".com", "",  "google.com/gmail/")
'google/gmail/'

Example for use of the map function:

>>> map(lambda x: len(x), ["one", "two", "three"])
[3, 3, 5]

(it replaces elements of array with length of those elements).

You can combine those two to get what you want.

Answer 3

Using the suggestion of George Shuklin this is the simplest code i could come up with.

---

import re

domains = ['.com', '.net', '.co', '.in']

urls = ["google.com","google.co.in","google.net","google.com/gmail/"]

for i in range(len(urls)):
    for domain in domains:
        urls[i] = re.sub(domain,"",urls[i])

print(urls)

---

This outputs:

['google', 'google', 'google', 'google/gmail/']

Answer 4

You can use re.sub and str.join :

import re
foo = ['.com', '.net', '.co', '.in']
urls = ["google.com","google.co.in","google.net","google.com/gmail/"]
final_result = [re.sub('|'.join(foo), '', i) for i in urls]

Output:

['google', 'google', 'google', 'google/gmail/']

Answer 5

Another alternative is to use str.replace() and str.find() .

foo = ['.com', '.net', '.co', '.in']
domains = ["google.com", "google.co.in", "google.net", "google.com/gmail/"]

def remove_extensions(domain, extensions):
    for ext in extensions:
        if domain.find(ext) != -1:
            domain = domain.replace(ext, "")
    return domain

list(map(lambda x: remove_extensions(x, foo), domains))

This code snippet outputs the result as expected:

['google', 'google', 'google', 'google/gmail/']