Export data from python to a txt file

Jason Swails jason.swails at gmail.com
Fri Mar 29 18:52:12 CET 2013

On Fri, Mar 29, 2013 at 1:33 PM, Ana Dionísio <anadionisio257 at gmail.com>wrote:

> Hello!!!
> I have this lists a=[1,3,5,6,10], b=[a,t,q,r,s] and I need to export it to
> a txt file and I can't use csv.

It would help if you showed exactly what you had in your program or in the
Python interpreter.  For instance

a = [1, 3, 5, 6, 10]
b = [a, t, q, r, s]

won't work, since it interprets the letters in the b-list as variables
rather than strings.  It would need to be

b = ['a', 't', 'q', 'r', 's']

or something equivalent.  Assuming you had that part correct:

> And I want the next format:
> a 1 3 5 6 10
> b a t q r s
> I already have this code:
> "f = open("test.txt", 'w')
>  f.write("a")
>  f.write("\n")
>  f.write("b")
>  f.write("\n")
>  for i in xrange(len(a)):
>     LDFile.write("\t")
>     LDFile.write(str(a[i]))
>     LDFile.write("\t")
>     LDFile.write(str(b[i]))
>  f.close()"
> But it doesn't have the format I want. Can you help?

Walk through exactly what the computer is doing here.  First it prints a,
then a newline, then b, then a newline:


Then your for loop executes (notice LDFile and f are different file
objects, so they won't write to the same location).  This will print a tab,
followed by the i'th element of a, followed by another tab, followed by the
i'th element of b.  So this:

a 1 3 5 6 10
b a t q r s

--begin-- [tab]  1 [tab]  a [tab]   3 [tab]   t [tab]   5 [tab]   q [tab]
6 [tab]   r [tab]   10 [tab]   s [tab]--end--

So the final file will look something like this:

     1     a     3     t     5     q     6     r     10     s

which is obviously not what you want.  The following code will do what you
want (although there are ways of doing this in less code, this is the most

for element in a:
   f.write(str(element) + '\t')
for element in b:
   f.write(str(element) + '\t')

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