学习Python拆分和联接？

Question

I thought I was understanding splits and joins in python but it is not working right for me.

lets say the value of inp[17] = 'Potters Portland Oregon school of magic'

# a string of data I am pulling from a csv file, the data comes through just fine.
loc = inp[17] 

l = loc.split(' ') # I want to split by the space

# I want to filter out all these words say they don't always 
# come as "School of magic" so I cant just filter that out they 
# could be mixed around at times.

locfilter = ['Potters', 'School', 'of', 'magic']     
locname = ' '.join([value for value in l if l not in locfilter])

At this point my locname variable should only have Portland Oregon in it, but it still has 'Potters Portland Oregon school of magic' it didn't filter out.

What have I done wrong I think the problem is in my locname = line.

Thanks for any help.

Answer 1

The problem here isn't your split or join , it's just a silly mistake in the condition in your list comprehension (the kind of silly mistake all of us make all the time):

locname = ' '.join([value for value in l if l not in locfilter])

Obviously l is never in locfilter . And if you fix that:

locname = ' '.join([value for value in l if value not in locfilter])

It works fine:

'Portland Oregon school'

Note that 'school' is still part of the output. That's because 'school' wasn't in locfilter ; 'School' was. If you want to match these case-insensitively:

lowerfilter = [value.lower() for value in locfilter]
locname = ' '.join([value for value in l if value.lower() not in lowerfilter])

And now:

'Portland Oregon'