如何从第二个字符串中的字符串中删除行？

Question

I have two strings:

String A:

machine1 volume1 Mon May 24 00:00:10 2021 
machine2 volume1 Mon May 24 00:00:03 2021 
machine2 volume2 Mon May 24 00:00:03 2021

String B:

machine1 volume2 Mon May 23 00:00:10 2021 
machine2 volume1 Mon May 23 00:00:03 2021 
machine2 volume2 Mon May 24 00:00:03 2021

And I would like to "remove" from String A, all the lines that are in String B, so the result could be something like:

New String A:

machine1 volume1 Mon May 24 00:00:10 2021 
machine2 volume1 Mon May 24 00:00:03 2021 

I tried with this:

avoid = set(s2.splitlines())
result = "\n".join(x for x in s1.splitlines() if x not in avoid)
print (result)

But the result still contains some lines from the second string...

Answer 1

You may have some padding spaces at the end of some lines, and a different amount between the s1 and the s2 , so you may use rstrip() to fix that

That will keep the leading spaces in the result

avoid = {x.rstrip() for x in s2.splitlines()}
result = "\n".join(x for x in s1.splitlines() if x.rstrip() not in avoid)

That will strip leading spaces in the result

avoid = {x.rstrip() for x in s2.splitlines()}
result = "\n".join(x.rstrip() for x in s1.splitlines() if x.rstrip() not in avoid)

Answer 2

Try this:

str1="machine1 volume1 Mon May 24 00:00:10 2021\nmachine2 volume1 Mon May 24 00:00:03 2021\nmachine2 volume2 Mon May 24 00:00:03 2021"
str2="machine1 volume2 Mon May 23 00:00:10 2021\nmachine2 volume1 Mon May 23 00:00:03 2021\nmachine2 volume2 Mon May 24 00:00:03 2021"
list1=str1.split("\n") #=== Convert to list
list2=str2.split("\n")
newlist=[x for x in list1 if x not in list2] #== list comprehension, if x in list2, add it to newlist
print(str(newlist)) 

Answer 3

I ran your code on Python 3.8.5, and got the output:

machine1 volume1 Mon May 24 00:00:10 2021 
machine2 volume1 Mon May 24 00:00:03 2021

which doesn't contain any strings from String B.

Perhaps look into how your strings are formatted, to see if there's any spaces or odd new line characters at the end of the lines throwing off the string comparison?

Answer 4

One liner,

sA = f'machine1 volume1 Mon May 24 00:00:10 2021\n\
machine2 volume1 Mon May 24 00:00:03 2021\n\
machine2 volume2 Mon May 24 00:00:03 2021'

sB = f'machine1 volume2 Mon May 23 00:00:10 2021 \n\
machine2 volume1 Mon May 23 00:00:03 2021\n\
machine2 volume2 Mon May 24 00:00:03 2021'
print('\n'.join(x for x in sA.splitlines() if x not in sB.splitlines()))