How to remove specific substrings from a set of strings in Python

Question

I have a set of strings set1  and all the strings in set1 have a two specific substrings which I don t need and want to remove   Sample Input  set1   Apple good   Orange good   Pear bad   Pear good   Banana bad   Potato bad   So basically I want the  good and  bad substrings removed from all the strings  What I tried   for x in set1      x replace   good          x replace   bad        But this doesn t seem to work at all  There is absolutely no change in the output and it is the same as the input  I tried using for x in list set1  instead of the original one but that doesn t change anything

User · Answer

if you delete something from list    u can use this way     method sub is case sensitive    new list      old list    ABCDEFG   HKLMNOP   QRSTUV    for data in old list       new list append re sub  AB M TV        data    print new list     output      CDEFG    HKL NOP    QRSTUV

User · Answer

I did the test  but it is not your example  and the data does not return them orderly or complete   gt  gt  gt  ind     p5   p1   p8   p4   p2   p8    gt  gt  gt  newind    x replace  p      for x in ind   gt  gt  gt  newind   1    2    8    5    4     I proved that this works    gt  gt  gt  ind     p5   p1   p8   p4   p2   p8    gt  gt  gt  newind    x replace  p      for x in ind   gt  gt  gt  newind   5    1    8    4    2    8     or   gt  gt  gt  newind       gt  gt  gt  ind     p5   p1   p8   p4   p2   p8    gt  gt  gt  for x in ind          newind append x replace  p        gt  gt  gt  newind   5    1    8    4    2    8

User · Answer

gt  gt  gt  x    Pear good   gt  gt  gt  y   x replace   good       gt  gt  gt  y  Pear   gt  gt  gt  x  Pear good     replace doesn t change the string  it returns a copy of the string with the replacement  You can t change the string directly because strings are immutable   You need to take the return values from x replace and put them in a new set

User · Answer

When there are multiple substrings to remove  one simple and effective option is to use re sub with a compiled pattern that involves joining all the substrings-to-remove using the regex OR     pipe   import re  to remove      good     bad   strings     Apple good   Orange good   Pear bad    p   re compile     join map re escape  to remove      escape to handle metachars  p sub     s  for s in strings      Apple    Orange    Pear

User · Answer

If list I was doing something for a list which is a set of strings and you want to remove all lines that have a certain substring you can do this import re def RemoveInList sub LinSplitUnOr       indices    i for i  x in enumerate LinSplitUnOr  if re search sub  x       A    i for j  i in enumerate LinSplitUnOr  if j not in indices      return A  where sub is a patter that you do not wish to have in a list of lines LinSplitUnOr for example A   Apple good   Orange good   Pear bad   Pear good   Banana bad   Potato bad   sub    good  A RemoveInList sub A   Then A will be

User · Answer

Update for Python 3 9 In python 3 9 you could remove suffix using str removesuffix  suffix   From the docs  If the string ends with the suffix string and that suffix is not empty  return string  -len suffix    Otherwise  return a copy of the original string  set1      Apple good   Orange good   Pear bad   Pear good   Banana bad   Potato bad    set2   set    for s in set1     set2 add s removesuffix  quot  good quot   removesuffix  quot  bad quot     or using set comprehension  set2    s removesuffix  quot  good quot   removesuffix  quot  bad quot   for s in set1      print set2    Output    Orange    Pear    Apple    Banana    Potato

User · Answer

Strings are immutable  string replace  python 2 x  or str replace  python 3 x  creates a new string  This is stated in the documentation      Return a copy of string s with all occurrences of substring old replaced by new        This means you have to re-allocate the set or re-populate it  re-allocating is easier with set comprehension    new set    x replace   good       replace   bad       for x in set1

User · Answer

practices 2 str    quot Amin Is A Good Programmer quot  new set   str replace  Good       print new set      print   Amin Is A  Programmer

User · Answer

All you need is a bit of black magic     gt  gt  gt  a     cherry bad   pear good    apple good    gt  gt  gt  a   list map lambda x  x replace   good      replace   bad      a    gt  gt  gt  a   cherry    pear    apple

User · Answer

You could do this   import re import string set1   Apple good   Orange good   Pear bad   Pear good   Banana bad   Potato bad    for x in set1      x replace   good           x replace   bad           x   re sub    good        x      x   re sub    bad        x      print x

[python] How to remove specific substrings from a set of strings in Python?

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