How to delete the first value and trailing comma from the 7th column in a csv file

Question

I am trying to remove the first value from the 31st column in a csv file. The columns are in quotes and separated by commas like so.

"first_name","last_name","home_address"
"Frank",Russel","123 Hampton road"

the 31st column is the image column and images are separated by commas

"http://ddd.com/124dfr3f.jpg,http://ddd.com/hjasgx37trg.jpg"

The first image and tailing comma has to be removed from the 31st column

Added - Here is an example.

"one","two","three","four","five","six","seven","eight","nine","ten","eleven","twelve","three","four","five","six","seven","eight","nine","ten","twenty-one","twenty-two","three","four","five","six","seven","eight","nine","ten","thirty-one","thirty-two","three","four","five","six","seven","eight","nine","forty"
"one","two","three","four","five","six","seven","eight","nine","ten","eleven","twelve","three","four","five","six","seven","eight","nine","ten","twenty-one","twenty-two","three","four","five","six","seven","eight","nine","http://pictures.domain.com/e/josequervo/1183/eeeffcc7927sssssssssss5d26c0eb19e1dc53548x.jpg","http://pictures.domain.com/e/josequervo/0083/eeef8cc7927bf1245d26c0eb19e1dc53545x.jpg,http://pictures.domain.com/e/josequervo/0099/eeefscc7927bf1245d26c0eb19e1dc53546x.jpg,http://pictures.domain.com/e/josequervo/0012/eeefdcc7927bf1245d26c0eb19e1dc53547x.jpg,http://pictures.domain.com/e/josequervo/1183/eeeffcc7927bf1245d26c0eb19e1dc53548x.jpg,http://pictures.domain.com/e/josequervo/1234/eeefgcc7927bf1245d26c0eb19e1dc53549x.jpg,http://pictures.domain.com/e/josequervo/asee/eeefhcc7927bf1245d26c0eb19e1dc53540x.jpg,http://pictures.domain.com/e/josequervo/2341/eeefjcc7927bf1245d26c0eb19e1dc53544x.jpg","two",three","four","five","six","seven","eight","nine","forty"

This url and comma has to be removed

http://pictures.domain.com/e/josequervo/0083/eeef8cc7927bf1245d26c0eb19e1dc53545x.jpg,

I only posted the first 2 lines of the csv file but the file is 300 - 400 lines and this image has to be removed from line 2 to the last line. We can't alter the first line.

Answer 1

Using GNU sed we may approach this as shown:

sed -e '
     s/","/&\n/30
     s/\n[^,]*,//
' file.csv

To be understood as:

• Place a placeholder at the 30th occurrence of the "," string in the current line.

• Then, traveling right from the placeholder all the way up to the first comma we delete everything along the way.

Other method is given as follows:

 perl -F'/","/' -lane 'my $i;
      print join q[","], map { $i++ == 30 ? substr($_, 1+index($_, ",")) : $_ } @F;
 ' input-file.csv

Method:

• perl will read the csv file on a line by line basis, and for each line it shall split it around the string "," and store the split elements in the array @F.

• Then for the 31st element, we remove everything up to the first comma.

Answer 2

As per your question understood image exsists in 31 st column seperated by comma and we need to remove first character from 31st column

awk -F "," '{$31=substr($31,2);print $0}' file.csv

Tested and its working fine Let us know for any confusion