Read/write 2D data from/to file..?

[mech point]

I was able to read the data from file into a two dimensional array
(lists)

rows=[map(float,line. split())for line in file("data")]

but How to write them back into the file.

Thank you,
srikanth

[John Machin]

Re: Read/write 2D data from/to file..?

On Feb 12, 12:47 pm, "mech point" <srikanth.a...@ gmail.comwrote:

I was able to read the data from file into a two dimensional array
(lists)
>
rows=[map(float,line. split())for line in file("data")]
>
but How to write them back into the file.

Presuming that it is either mandatory to adopt the same style (or lack
thereof) as the input code, and/or futile to suggest otherwise:

file('data2','w ').write('\n'.j oin(' '.join(repr(ite m)for item in
row)for row in rows)+'\n')

[Grant Edwards]

Re: Read/write 2D data from/to file..?

On 2007-02-12, mech point <srikanth.allu@ gmail.comwrote:

>
I was able to read the data from file into a two dimensional array
(lists)
>
rows=[map(float,line. split())for line in file("data")]
>
but How to write them back into the file.

for r in rows:
file.write(" ".join(map(str, r)) + "\n")

--
Grant Edwards grante Yow! My nose feels like a
at bad Ronald Reagan movie...
visi.com

[Gabriel Genellina]

Re: Read/write 2D data from/to file..?

En Sun, 11 Feb 2007 22:47:30 -0300, mech point <srikanth.allu@ gmail.com>
escribió:

I was able to read the data from file into a two dimensional array
(lists)
>
rows=[map(float,line. split())for line in file("data")]
>
but How to write them back into the file.

This way uses the same structures as your example; line.split(",") ->
",".join(.. .); map(float,...) -map(str,...)

yourfile.writel ines(",".join(m ap(str,row))+"\ n" for row in rows)

If you are using Python<2.5, put [] inside the writelines call:
writelines([","...]).
Or move the iteration outer. If you want control on the format too:
for row in rows:
yourfile.write( "%.2f,%.6g\ n" % (row[0], row[1]))

--
Gabriel Genellina

[Grant Edwards]

Re: Read/write 2D data from/to file..?

On 2007-02-12, Grant Edwards <grante@visi.co mwrote:

On 2007-02-12, mech point <srikanth.allu@ gmail.comwrote:

>>
>I was able to read the data from file into a two dimensional array
>(lists)
>>
>rows=[map(float,line. split())for line in file("data")]
>>
>but How to write them back into the file.

>
for r in rows:
file.write(" ".join(map(str, r)) + "\n")

Doh. Bad choice of names for my file object:

f = file("data","w" )
for r in rows:
f.write(" ".join(map(str, r)) + "\n")

You can do it on one line if you want, but I find the above a
little bit clearer.

--
Grant Edwards grante Yow! Spreading peanut
at butter reminds me of
visi.com opera!! I wonder why?

[Vasily Sulatskov]

Re: Read/write 2D data from/to file..?

On Feb 12, 6:47 am, "mech point" <srikanth.a...@ gmail.comwrote:

I was able to read the data from file into a two dimensional array
(lists)
>
rows=[map(float,line. split())for line in file("data")]
>
but How to write them back into the file.

Using matplotlib it will be:

import pylab
rows = pylab.load('src .dat')
pylab.save(rows , 'dst.dat')