Re: [Tutor] Output of list
Dear Emil,
I want to be capable of converting a string into a list where all
the items, in the list, have a fixed length not equal to 1 e.g i
have k = 'abcdefgh' and I want the fixed length for all the the
items to be 2 then the list would look like ['ab', 'cd', 'ef, 'gh'].
How do i do this?
- Emil
It is nice place to use a generator:
def pairs(sliceit):
streamlist = list(sliceit)
streamlist.reverse()
while streamlist:
pair = streamlist.pop()
try:pair += streamlist.pop()
except: pass
yield pair
## Probably it is easier to understand
def pairs2(sliceit):
try:
while sliceit:
yield sliceit[:2]
sliceit = sliceit[2:]
except: # oops, it was odd length
yield sliceit
print '_'.join(e for e in pairs('abcd'))
print '_'.join(e for e in pairs('abcde'))
print '_'.join(e for e in pairs2('abcd'))
print '_'.join(e for e in pairs2('abcde'))
Best Regards,
Janos
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Re: [Tutor] Output of list
János Juhász wrote: It is nice place to use a generator: def pairs(sliceit): streamlist = list(sliceit) streamlist.reverse() while streamlist: pair = streamlist.pop() try:pair += streamlist.pop() except: pass yield pair ## Probably it is easier to understand def pairs2(sliceit): try: while sliceit: yield sliceit[:2] sliceit = sliceit[2:] except: # oops, it was odd length yield sliceit ... Or, by extending Alan's solution ... def splitStringByN(s, n): for m in range(0, len(s), n): yield s[m:m+n] k = 'abcdefghi' list(splitStringByN(k, 2)) As it turns out, this is similar to an ASPN Cookbook recipe contributed by Dmitry Vasiliev: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/302069 HTH, Marty ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Output of list
Dear Marty, ... Or, by extending Alan's solution ... def splitStringByN(s, n): for m in range(0, len(s), n): yield s[m:m+n] k = 'abcdefghi' list(splitStringByN(k, 2)) It seems to be the most readable solution for me. As it turns out, this is similar to an ASPN Cookbook recipe contributed by Dmitry Vasiliev: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/302069 HTH, Marty Thanks for the link. Best regards, Janos ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Output of list
János Juhász wrote: Dear Marty, Hi Janos, ... Or, by extending Alan's solution ... def splitStringByN(s, n): for m in range(0, len(s), n): yield s[m:m+n] k = 'abcdefghi' list(splitStringByN(k, 2)) It seems to be the most readable solution for me. For completeness, one could also pull it out of the function def and use a generator expression directly. If I'm not mistaken, this would be more or less equivalent: k = 'abcdefghi' list((k[m:m+2] for m in range(0, len(k), 2))) As it turns out, this is similar to an ASPN Cookbook recipe contributed by Dmitry Vasiliev: http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/302069 HTH, Marty Thanks for the link. No problem. Happy Holidays! Marty ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Output of list
Emil wrote:
hey
I want to be capable of converting a string into a list where all the items,
in the list, have a fixed length not equal to 1 e.g i have k = 'abcdefgh'
and I want the fixed length for all the the items to be 2 then the list would
look like ['ab', 'cd', 'ef, 'gh']. How do i do this?
map(''.join, zip(k[::2], k[1::2]))
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Re: [Tutor] Output of list
Emil wrote: hey I want to be capable of converting a string into a list where all the items, in the list, have a fixed length not equal to 1 e.g i have k = 'abcdefgh' and I want the fixed length for all the the items to be 2 then the list would look like ['ab', 'cd', 'ef, 'gh']. How do i do this? Also : [''.join(i) for i in zip(k[::2], k[1::2])] ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Output of list
Ricardo Aráoz wrote: Emil wrote: hey I want to be capable of converting a string into a list where all the items, in the list, have a fixed length not equal to 1 e.g i have k = 'abcdefgh' and I want the fixed length for all the the items to be 2 then the list would look like ['ab', 'cd', 'ef, 'gh']. How do i do this? Also : [''.join(i) for i in zip(k[::2], k[1::2])] Cool use of 'zip' and extended slicing! Just thought I would add that 'zip' truncates after the shortest sequence, which would cause data loss for strings of odd length -- of course, the OP may not consider this a problem. In [1]: k = 'abcdefghi' # - note the 'i' In [2]: len(k) Out[2]: 9 In [3]: [''.join(i) for i in zip(k[::2], k[1::2])] Out[3]: ['ab', 'cd', 'ef', 'gh'] # - 'i' is gone HTH, Marty ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Output of list
Emil [EMAIL PROTECTED] wrote I want to be capable of converting a string into a list where all the items, in the list, have a fixed length not equal to 1 You can use list slicing to do this. Combine with the stepsize parameter of the range function k = 'abcdefgh' and I want the fixed length for all the the items to be 2 then the list would look like ['ab', 'cd', 'ef, 'gh']. k = 'abcdefgh' new = [] for n in range(0,len(k),2): # 2=stepsize new.append(k[n:n+2]) # use slice print new As a list comprehension that would be: new = [k[n:n+2] for n in range(0,len(k),2)] And as a more general function: def splitStringByN(s,n): return [s[m:m+n] for m in range(0,len(s),n)] Should work, HTH, -- Alan Gauld Author of the Learn to Program web site http://www.freenetpages.co.uk/hp/alan.gauld ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Output of list
Martin Walsh wrote: Ricardo Aráoz wrote: Emil wrote: hey I want to be capable of converting a string into a list where all the items, in the list, have a fixed length not equal to 1 e.g i have k = 'abcdefgh' and I want the fixed length for all the the items to be 2 then the list would look like ['ab', 'cd', 'ef, 'gh']. How do i do this? Also : [''.join(i) for i in zip(k[::2], k[1::2])] Cool use of 'zip' and extended slicing! Thx Just thought I would add that 'zip' truncates after the shortest sequence, which would cause data loss for strings of odd length -- of course, the OP may not consider this a problem. In [1]: k = 'abcdefghi' # - note the 'i' In [2]: len(k) Out[2]: 9 In [3]: [''.join(i) for i in zip(k[::2], k[1::2])] Out[3]: ['ab', 'cd', 'ef', 'gh'] # - 'i' is gone Could only think of : [''.join(i) for i in zip(k[::2], k[1::2])] + list(k)[-(len(k)%2):0:-len(k)] But maybe it is too complicated. There should be a simpler way. ___ Tutor maillist - Tutor@python.org http://mail.python.org/mailman/listinfo/tutor
