CODEWITHSUNDEEP
pythonstringlistaddition
O.rka
O.rka

Reputation: 30687

Add two different values to string from different lists

so i have two different lists of strings; i.e. x and y. 

len(y) = len(x) - 1

i want to add them together in an empty string in the original order so basically the output = x1 + y1 + x2 + y2 + x3

x = ['AAA','BBB','CCC']
y = ['abab','bcbcb']

#z = ''
z = 'AAAababBBBbcbcbCCC'

how can i create a for-loop to add to this empty string z ?

i usually would do:

for p,q in zip(x,y):

but since y in smaller than x, it wouldn't add the last value of x

Upvotes: 0

Views: 187

Answers (4)

CornSmith
CornSmith

Reputation: 2037

from itertools import izip_longest

x = ['AAA','BBB','CCC']
y = ['abab','bcbcb']

unfinished_z = izip_longest( x,y,fillvalue='' ) # an iterator
unfinished_z = [ ''.join( text ) for text in unfinished_z ] # a list
z = ''.join( unfinished_z ) # the string AAAababBBBbcbcbCCC

I prefer more verbosity.

Upvotes: 0

Ashwini Chaudhary
Ashwini Chaudhary

Reputation: 250951

You can use the roundrobin recipe from itertools:

from itertools import *
def roundrobin(*iterables):
    "roundrobin('ABC', 'D', 'EF') --> A D E B F C"
    # Recipe credited to George Sakkis
    pending = len(iterables)
    nexts = cycle(iter(it).next for it in iterables)
    while pending:
        try:
            for next in nexts:
                yield next()
        except StopIteration:
            pending -= 1
            nexts = cycle(islice(nexts, pending))
x = ['AAA','BBB','CCC']
y = ['abab','bcbcb']
print "".join(roundrobin(x,y))  
#AAAababBBBbcbcbCCC

Or with itertools.izip_longest you could do:

>>> from itertools import izip_longest
>>> ''.join([''.join(c) for c in izip_longest(x,y,fillvalue = '')])
'AAAababBBBbcbcbCCC'

Upvotes: 0

crayzeewulf
crayzeewulf

Reputation: 6010

This ought to do it:

''.join([item for sublist in zip(x, y+['']) for item in sublist])

Upvotes: 1

inspectorG4dget
inspectorG4dget

Reputation: 113955

You want itertools.izip_longest. Also, check out this other post

newStr = ''.join(itertools.chain.from_iterable(
                   itertools.izip_longest(x,y, fillvalue='')
                 ))

Upvotes: 0

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