Extracting specific columns from a file to create new file in python

Question

I have a file that looks something like this:

o 345644 0 0 0 1
0 454545 0 0 2 2
0 423233 0 0 1 1
. .      . . . .
. .      . . . .
. .      . . . .

What I would like to do is extract column two and column 6 to create a text file. I wrote the following code but the output file I am getting only contains the second column. The desired output I am would like is a new file that looks like this:

newfile.txt

Here is my code :

dta_2path = open("file.txt","r")
ws_2= open("newfile.txt", "w")

for line in dta_2path:
    if line.strip():
       ws_2.write("\t".join(line.split()[1:2]+ line.split()[9:10])+"\n") 

dta_2path.close()
ws_2.close()

Any help in how to fix this would be appreciated. Thanks in advance!

Seems like 9:10 should be 5:6. But you're only extracting one column, so why not use line.split()[1] and lines.split()[5] ? — aghast
– aghast, Commented May 5, 2016 at 17:20
I used line.split()[1] and line.split()[5] but I get a syntax error in dta_2path.close(). Not sure why. — An P.
– An P., Commented May 5, 2016 at 17:33

aghast · Accepted Answer · 2016-05-05 18:10:31Z

2

Try this:

for line in dta_2path:
    if line.strip():
        cols = line.split()
        ws_2.write(cols[1] + "\t" + cols[5] + "\n")

edited May 5, 2016 at 18:10

answered May 5, 2016 at 17:40

aghast

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3 Comments

An P. Over a year ago

I get the following error: ws_2.write(cols[1], "\t", cols[5], "\n") TypeError: function takes exactly 1 argument (4 given)

aghast Over a year ago

Grrr! You're right, have to use concatenation. I've edited it with '+' instead of ','

An P. Over a year ago

Thanks! That makes sense now.

Supahupe · Accepted Answer · 2016-05-05 17:23:51Z

0

You are taking the wrong indices. It should work if you use line.split(" ")[1] and line.split(" ")[5].

answered May 5, 2016 at 17:23

Supahupe

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1 Comment

An P. Over a year ago

I was adding the indices [1:2] and [9:10] because I was counting the spaces too. I changed to what you said but it didn't work.

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