How to use Awk to format numbers with a thousands separator

awktext formattingtext processing

Can anyone tell me how to use the awk command for this statement "the number will contain commas after every three digits. For example, 100000000 will become 100,000,000."

I know how to use sed command to obtain this output but I don't know how to use awk, I'm beginner please tell me I'm searching from morning but I didn't get a suitable answer for this so please suggest me best tutorials for learning.

sed command to get the above output:

echo "100000000" | sed -E 's/([0-9]{3})/,\1/2g'

Best Answer

A locale-independent solution with manual formatting

This should work on any POSIX-compatible OS regardless of the locales installed.

$ printf "1\n10\n100\n1000\n10000\n100000\n1000000\n10000000\n100000000\n" \
| awk '{ len=length($0); res=""; for (i=0;i<=len;i++) { res=substr($0,len-i+1,1) res; if (i > 0 && i < len && i % 3 == 0) { res = "," res } }; print res }'
1
10
100
1,000
10,000
100,000
1,000,000
10,000,000
100,000,000

A solution that uses `printf` and the en_US locale.

The printf sequence %'d prints a decimal integer formatted with the current locale's thousands separator.

$ printf "1\n10\n100\n1000\n10000\n100000\n1000000\n10000000\n100000000\n" \
| LC_ALL=en_US.UTF-8 awk '{ printf("%'"'"'d\n", $0) }'
1
10
100
1,000
10,000
100,000
1,000,000
10,000,000
100,000,000

Related Solutions

Split column after nth character

Here is a solution with awk. It separates first four characters and rest of the 2nd column into two variables and print them.

]$ awk '{s=substr($2,1,4)}{g=substr($2,5,length($2))}{print $1,s,g}' file.txt
1A THIS ISATEST
1B THAT ISATEST

Linux – How to correctly format the output with Awk printf command

You have the fields in the right order, but your first print statement adds a newline (Output Record Separator), so your data's there, but just wrapped unexpectedly.

The second issue is that you're telling printf to use a width of 4; that includes the decimal point and the two digits after it, leaving only one for the leading digit and none for any padding. Try using 5 as the width, so that your data is padded up to four total numbers. If you want 4 digits before the decimal point, then change the width to 7 instead.

This is the shortest change I made from your program to something that outputs what I think you want:

awk -F"|" '{
  format = "%05.2f,%05.2f,%05.2f"; 
  print $1","$2","$3","$4"," sprintf(format, $5,$6,$7)}' filename

I combined multiple { } blocks into one, and also combined the print statements into one.

If I was to write your awk statement from scratch, I might do something like this:

awk -v FS=\| -v OFS=, '{
  $5=sprintf("%05.2f", $5); 
  $6=sprintf("%05.2f", $6); 
  $7=sprintf("%05.2f", $7); 
  print $1,$2,$3,$4,$5,$6,$7}' filename

It explicitly sets the input Field Separator, the Output Field Separator, explicitly converts each of the fields on its own, then prints the desired fields, with the OFS separating them.