Grabbing values from within a list of string arrays?

How do you select/grab the values within a list of string arrays?

When I execute a code to read the contents in my files, it is as follows:

for line in testFile:
test = line.split()

#Output:
['1', '21', '32', '43', '54', '65', '76', '87']
['2', '31', '42', '53', '64', '75', '86', '97']
['3', '41', '52', '63', '74', '85', '96', '107']
...
...

However, now supposedly I would like to select and grab the first values - 1,2,3 in the output only, I got ['1', '21', '32', '43', '54', '65', '76', '87'] or the values of the last line, should I code it print test[0] or for item in test..

Meaning to say, if I decided to grab the values of column 3, it will gives me 32,42,52, and if I grab column 6, it will gives me 65,75,85 etc The number of columns are the same through and I asked this because I am either going to set the values in the rotation/translation attibutes while the first column being the frame number...

Is it possible to do so?

Solution

You just need to transpose the contents, with zip function, like this

with open("inputfile") as f:
    rows = zip(*[line.split() for line in f])

print rows[0]

We open the file with open and the with statement. Then, we read line by line and split every read line. So, we get a list of lists. Now, we apply each of those lists to zip function, which actually transposes them. After transposing, the rows become columns and the columns become rows. For example,

[[1, 2, 3]
 [4, 5, 6]
 [7, 8, 9]]

will become

[[1, 4, 7]
 [2, 5, 8]
 [3, 6, 9]]