CODEWITHSUNDEEP
pythonpython-2.7
BenH
BenH

Reputation: 720

List with exclusive options

If I have a list of options that are being fed to a rest call like so:

[ 'allX', 'noX', 'noY', 'allY', 'var1', 'var2' ]

(The actual list is quite long)

Only one of '*X' can be included. Only one of '*Y' can be included. Any of the single item variables like var1 and var2 can be used with any combination of options.

Basically I wanna avoid a long kludge of if-then statements checking if allX and noX were provided together, ditto for the next pair, and so on.

Is there a handy python module for doing this or what is the most pythonic way of asserting this requirement? I have no control over the list itself, so tackling this from that end is not an option.

Thanks for any help.

Upvotes: 0

Views: 86

Answers (1)

Ajax1234
Ajax1234

Reputation: 71471

To cut down on control statements, you can try this:

from itertools import groupby, chain

new_data = list(chain.from_iterable([[list(b)[0]] if a.isupper() else list(b) for a, b in groupby(s, key=lambda x: x[-1])]))

Output:

['allX', 'noY', 'var1', 'var2']

To make your algorithm as generic as possible, you can try this:

s = [ 'allX', 'noX', 'noY', 'allY', 'var1', 'var2' ]
import re
last = []
second_last = []
for i in s:
    if re.findall("[A-Z]$", i):
         if i[-1] not in second_last:
              last.append(i)
              second_last.append(i[-1])
    else:
       last.append(i)
print(last)

Output:

['allX', 'noY', 'var1', 'var2']

Upvotes: 3

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