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Python

Posted by Mousa Alqarni
Mousa Alqarni
22,619 Points

how to remove word in string like common words ( and , or , # , / , low) in pyathon3

how to remove word in string like common words ( and , or , # , / ) in pyathon3 some times words small or cap letter ..

str = "SY-LCP LOW BEND MEDIAL DISTAL TIBIA PLATE 3.5   # 01.112.062"

print (str.split( ))

2 Answers

Chris Freeman
MOD
Chris Freeman
Treehouse Moderator 68,332 Points
Chris Freeman
Chris Freeman
Treehouse Moderator 68,332 Points

Using str.replace() requires scanning the entire string for each unique element you wish to replace. This is inefficient for lots of changes.

You can use the regular expression re.sub() to remove all specific characters in one pass. You can also compare to a "bad word" set. Examples below

It's not a good practice to use python base type str as variable name. Using "string" instead. 

import re

>>> import re
>>> 
>>> string = "SY-LCP LOW BEND MEDIAL DISTAL TIBIA PLATE 3.5   # 01.112.062"
>>> string
'SY-LCP LOW BEND MEDIAL DISTAL TIBIA PLATE 3.5   # 01.112.062'
# remove #, (, /
>>> stripped = re.sub(r'[#(/]', "", string)
>>> stripped
'SY-LCP LOW BEND MEDIAL DISTAL TIBIA PLATE 3.5    01.112.062'
# remove words of 3 or less characters
>>> no_small_words = re.sub(r'\b\w{,3}\b', "", string)
>>> no_small_words
'-  BEND MEDIAL DISTAL TIBIA PLATE .   # ..'

>>> string2 = "This Scat Scan"
# Remove Capitol letters
>>> no_caps = re.sub(r'[A-Z]', "", string2)
>>> no_caps
'his cat can'

>>> bad_word_set = {"TIBIA", "PLATE"}
# add words using `add`
>>> bad_word_set.add("BEND")
>>> no_small_words
'-  BEND MEDIAL DISTAL TIBIA PLATE .   # ..'
# remove all words in "bad" set
>>> no_bad_words = " ".join([x 
...                         for x in no_small_words.split()
...                         if x not in bad_word_set])
>>> no_bad_words
'- MEDIAL DISTAL . # ..'
>>>
Steven Parker
Steven Parker
224,836 Points
Steven Parker
Steven Parker
224,836 Points

You can easily modify a string using the "replace" method. For instance, to create a new string from the above example but without the "#" character (or the following space):

newstr = str.replace("# ", "")

For more sophisticated manipulations, you might want to look into the "regular expression" functions. There's a course here for that: Regular Expressions in Python.