How do I calculate the mean of a column

Question

Anyone know how can I calculate the mean of one these columns (on linux)??

sda               2.91    20.44    6.13    2.95   217.53   186.67    44.55     0.         


        

Answer 1

Perl solution:

perl -lane '$total += $F[1]; END{print $total/$.}' file

-a autosplits the line into the @F array, which is indexed starting at 0
$. is the line number

If your fields are separated by commas instead of whitespace:

perl -F, -lane '$total += $F[1]; END{print $total/$.}' file

To print mean values of all columns, assign totals to array @t:

perl -lane 'for $c (0..$#F){$t[$c] += $F[$c]}; END{for $c (0..$#t){print $t[$c]/$.}}' 

output:

0
0.485
14.38
1.74
0.888333333333333
77.27
49.8266666666667
39.91
1.29833333333333
434.131666666667