Create all possible variations for a string with hyphens

Question

I have a list of hyphenated strings, e.g:

myList = ['mother-in-law', 'co-operation', 'sixty-nine-eighty-ninths']

For every element of this list I want to be able to create all the variations where the hyphen is between two or more of the tokens of every element:

mother-in law
mother in-law
sixty-nine eighty ninths
sixty-nine-eighty ninths
sixty nine-eighty-ninths
sixty-nine eighty-ninths
sixty nine-eighty ninths
sixty nine eighty-ninths
...

I tried the solution from this question (Create variations of a string)
But I can’t figure how to adapt it:

from itertools import combinations
myList = ['mother-in-law', 'co-operation', 'sixty-nine-eighty-ninths']

for e in myList :
    for i in range(len(e.split("-"))):
        for indices in combinations(range(len(e.split("-"))), i):
            print(''.join([e.split("-")[x] if x in indices else '-' for x in range(len(e))]))

This is what I get:

-------------
mother------------
-in-----------
--law----------
motherin-----------
mother-law----------
-inlaw----------
------------
co-----------
-operation----------
------------------------
sixty-----------------------
-nine----------------------
--eighty---------------------
---ninths--------------------
sixtynine----------------------
sixty-eighty---------------------
sixty--ninths--------------------
-nineeighty---------------------
-nine-ninths--------------------
--eightyninths--------------------
sixtynineeighty---------------------
sixtynine-ninths--------------------
sixty-eightyninths--------------------
-nineeightyninths--------------------

Asked By: MMM

||

Source

Answer 1

It might be a little easier to just make your own generator to produce the combinations. This can be done in a very readable way with a recursive generator so long as your strings aren’t gigantic enough to run into stack limits:

def hyphenCombos(s):
    head, _, rest = s.partition('-')
    if len(rest) == 0:
        yield head
    else:
        for c in hyphenCombos(rest):
            yield f'{head}-{c}'
            yield f'{head} {c}'

s = 'sixty-nine-eighty-ninths'
list(hyphenCombos(s))

Result:

['sixty-nine-eighty-ninths',
 'sixty nine-eighty-ninths',
 'sixty-nine eighty-ninths',
 'sixty nine eighty-ninths',
 'sixty-nine-eighty ninths',
 'sixty nine-eighty ninths',
 'sixty-nine eighty ninths',
 'sixty nine eighty ninths']

With that you can use it in a comprehension or pass it to other itertools functions to do whatever you need:

myList = ['mother-in-law', 'co-operation', 'sixty-nine-eighty-ninths']
chain.from_iterable(hyphenCombos(s) for s in myList))
# or variations...
# [list(hyphenCombos(s)) for s in myList]

Answered By: Mark

Answer 2

Looking a little bit through the tools that itertools provides, I found product could be most useful here. It lets us go through all the possibilities of having a space or a dash between two words.

from itertools import product, zip_longest

my_list = ['mother-in-law', 'co-operation', 'sixty-nine-eighty-ninths']
symbols = ' ', '-'

for string in my_list:
    string_split = string.split('-')
    for symbols_product in product(symbols, repeat=len(string_split)-1):
        if '-' not in symbols_product:
            continue
        rtn = ""
        for word, symbol in zip_longest(string_split, symbols_product, fillvalue=''):
            rtn += word + symbol
        print(rtn)
    print()

Also, I’m skipping the iterations where there’s no dash between any two words, as per your request.

Output:

mother in-law
mother-in law
mother-in-law

co-operation

sixty nine eighty-ninths
sixty nine-eighty ninths
sixty nine-eighty-ninths
sixty-nine eighty ninths
sixty-nine eighty-ninths
sixty-nine-eighty ninths
sixty-nine-eighty-ninths

Answered By: AndreiToroplean

Create all possible variations for a string with hyphens

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