Joining pairs of elements of a list

Question

I know that a list can be joined to make one long string as in   x     a    b    c    d   print    join x    Obviously this would output    abcd    However  what I am trying to do is simply join the first and second strings in the list  then join the third and fourth and so on  In short  from the above example instead achieve an output of     ab    cd     Is there any simple way to do this  I should probably also mention that the lengths of the strings in the list will be unpredictable  as will the number of strings within the list  though the number of strings will always be even  So the original list could just as well be      abcd    e    fg    hijklmn    opq    r

User · Answer

Well I would do it this way as I am no good with Regs..

CODE

t = '1. eat, food\n\
7am\n\
2. brush, teeth\n\
8am\n\
3. crack, eggs\n\
1pm'.splitlines()

print [i+j for i,j in zip(t[::2],t[1::2])]

output:

['1. eat, food   7am', '2. brush, teeth   8am', '3. crack, eggs   1pm']

Hope this helps :)

User · Answer

just to be pythonic  -    gt  gt  gt  x     a1sd   23df   aaa   ccc   rrrr    ssss    e        gt  gt  gt   x i    x i 1  for i in range 0 len x  2     a1sd23df    aaaccc    rrrrssss    e     in case the you want to be alarmed if the list length is odd you can try    x i    x i 1  if not len x   2 else  odd index  for i in range 0 len x  2     Best of Luck

User · Answer

gt  gt  gt  lst      abcd    e    fg    hijklmn    opq    r     gt  gt  gt  print  lst 2 i  lst 2 i 1  for i in range len lst  2     abcde    fghijklmn    opqr

User · Answer

Without building temporary lists    gt  gt  gt  import itertools  gt  gt  gt  s    abcdefgh   gt  gt  gt  si   iter s   gt  gt  gt      join each  for each in itertools izip si  si     ab    cd    ef    gh     or    gt  gt  gt  import itertools  gt  gt  gt  s    abcdefgh   gt  gt  gt  si   iter s   gt  gt  gt  map    join  itertools izip si  si     ab    cd    ef    gh

User · Answer

You can use slice notation with steps    gt  gt  gt  x    abcdefghijklm   gt  gt  gt  x 0  2   0  2  4     acegikm   gt  gt  gt  x 1  2   1  3  5     bdfhjl   gt  gt  gt   i j for i j in zip x   2   x 1  2      zip makes  0 1   2 3        ab    cd    ef    gh    ij    kl     Same logic applies for lists too  String lenght doesn t matter  because you re simply adding two strings together

User · Answer

Use an iterator     List comprehension    gt  gt  gt  si   iter   abcd    e    fg    hijklmn    opq    r     gt  gt  gt   c next si      for c in si    abcde    fghijklmn    opqr      Very efficient for memory usage  Exactly one traversal of s   Generator expression    gt  gt  gt  si   iter   abcd    e    fg    hijklmn    opq    r     gt  gt  gt  pair iter    c next si      for c in si   gt  gt  gt  pair iter   can be used in a for loop  lt generator object at 0x4ccaa8 gt   gt  gt  gt  list pair iter     abcde    fghijklmn    opqr      use as an iterator   Using map  str   add    iter   gt  gt  gt  si   iter   abcd    e    fg    hijklmn    opq    r     gt  gt  gt  map str   add    si  si    abcde    fghijklmn    opqr     next iterator   default   is available starting in Python 2 6

[python] Joining pairs of elements of a list

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