Use Awk to Print every character as its own column? - awk

Question

I am in need of reorganizing a large CSV file. The first column, which is currently a 6 digit number needs to be split up, using commas as the field separator.
For example, I need this:
022250,10:50 AM,274,22,50
022255,11:55 AM,275,22,55
turned into this:
0,2,2,2,5,0,10:50 AM,274,22,50
0,2,2,2,5,5,11:55 AM,275,22,55
Let me know what you think!
Thanks!

Answer 1

It's a lot shorter in perl:
perl -F, -ane '$,=","; print split("",$F[0]), #F[1..$#F]' <file>
Since you don't know perl, a quick explanation. -F, indicates the input field separator is the comma (like awk). -a activates auto-split (into the array #F), -n implicitly wraps the code in a while (<>) { ... } loop, which reads input line-by-line. -e indicates the next argument is the script to run. $, is the output field separator (it gets set iteration of the loop this way, but oh well). split has obvious purpose, and you can see how the array is indexed/sliced. print, when lists as arguments like this, uses the output field separator and prints all their fields.
In awk:
awk -F, '{n=split($1,a,""); for (i=1;i<=n;i++) {printf("%s,",a[i])}; for (i=2;i<NF;i++) {printf("%s,",$i)}; print $NF}' <file>

Answer 2

I think this might work. The split function (at least in the version I am running) splits the value into individual characters if the third parameter is an empty string.
BEGIN{ FS="," }
{
n = split( $1, a, "" );
for ( i = 1; i <= n; i++ )
printf("%s,", a[i] );
sep = "";
for ( i = 2; i <= NF; i++ )
{
printf( "%s%s", sep, $i );
sep = ",";
}
printf("\n");
}

Answer 3

here's another way in awk
$ awk -F"," '{gsub(".",",&",$1);sub("^,","",$1)}1' OFS="," file
0,2,2,2,5,0,10:50 AM,274,22,50
0,2,2,2,5,5,11:55 AM,275,22,55

Answer 4

Here's a variation on a theme. One thing to note is it prints the remaining fields without using a loop. Another is that since you're looping over the characters in the first field anyway, why not just do it without using the null-delimiter feature of split() (which may not be present in some versions of AWK):
awk -F, 'BEGIN{OFS=","} {len=length($1); for (i=1;i<len; i++) {printf "%s,", substr($1,i,1)}; printf "%s", substr($1,len,1);$1=""; print $0}' filename
As a script:
BEGIN {FS = OFS = ","}
{
len = length($1);
for (i=1; i<len; i++)
{printf "%s,", substr($1, i, 1)};
printf "%s", substr($1, len, 1)
$1 = "";
print $0
}