Re: Re: joining two column

[mannu jha]

On Sat, 15 May 2010 00:14:05 +0530  wrote
>On 05/14/2010 12:55 PM, James Mills wrote:

>> file1:

>> a1 a2

>> a3 a4

>> a5 a6

>> a7 a8

>>

>> file2:

>> b1 b2

>> b3 b4

>> b5 b6

>> b7 b8

>>

>> and I want to join them so the output should look like this:

>>

>> a1 a2 b1 b2

>> a3 a4 b3 b4

>> a5 a6 b5 b6

>> a7 a8 b7 b8

>

> This is completely untested, but this "should" (tm) work:

>

> from itertools import chain

>

> input1 = open("input1.txt", "r").readlines()

> input2 = open("input2.txt", "r").readlines()

> open("output.txt", "w").write("".join(chain(input1, input2)))



I think you meant izip() instead of chain() ... the OP wanted to 

be able to join the two lines together, so I suspect it would 

look something like



  # OPTIONAL_DELIMITER = " "

  f1 = file("input1.txt")

  f2 = file("input2.txt")

  out = open("output.txt", 'w')

  for left, right in itertools.izip(f1, f2):

   out.write(left.rstrip('\r\n'))

   # out.write(OPTIONAL_DELIMITER)

   out.write(right)

  out.close()



This only works if the two files are the same length, or (if 

they're of differing lengths) you want the shorter version. The 

itertools lib also includes an izip_longest() function with 

optional fill, as of Python2.6 which you could use instead if you 

need all the lines



-tkc









-- 

with this 
from itertools import chain
# OPTIONAL_DELIMITER = " "
f1 = file("input1.txt")
f2 = file("input2.txt")
out = open("output.txt", 'w')
for left, right in itertools.izip(f1, f2):
  out.write(left.rstrip('\r\n'))
    # out.write(OPTIONAL_DELIMITER)
  out.write(right)
out.close()

it is showing error:
ph08001 at linux-af0n:~> python join.py
Traceback (most recent call last):
  File "join.py", line 6, in 
    for left, right in itertools.izip(f1, f2):
NameError: name 'itertools' is not defined
ph08001 at linux-af0n:~>



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