gawk: Summing floats formatted with comma separator

Question

I'm trying to sum floats which use the comma as separator, and gawk does integer calculations. Here's the script:

BEGIN {
  FS=";"
  OFS=";"
  CONVFMT = "%2.2f"
}
{ 
  print $1
  print $2
  print $1+$2 
}

I'm using this data file:

4,3;5,7

and calling the script like this:

LC_ALL=fr_BE gawk -f test.awk < t.txt

I get this output:

4,3
5,7
9

I have the fr_BE locale set up, but the result is still incorrect. How can I fix this?

Answer 1

The answer is to use the --use-lc-numeric gawk option.

--use-lc-numeric

This forces gawk to use the locale's decimal point character when parsing input data. Although the POSIX standard requires this behavior, and gawk does so when --posix is in effect, the default is to follow traditional behavior and use a period as the decimal point, even in locales where the period is not the decimal point character. This option overrides the default behavior, without the full draconian strictness of the --posix option.

Example

Say we have this data file:

$ cat t.txt 
4,3;5,7
4,9;5,7

To ease in seeing the output, I changed this line in test.awk:

print "Total: "$1+$2 

Now when you run it using the above mentioned switch:

$ LC_ALL=fr_BE gawk --use-lc-numeric -f test.awk < t.txt
4,3
5,7
Total: 10
4,9
5,7
Total: 10,60

References

• gawk floating-point number localization
• 6.1.4 Conversion of Strings and Numbers

Answer 2

I think the problem is gawk can not convert string 4,3 to a float number. You can fix it by replace , with .. For @glenn jackman input:

BEGIN {
  FS=";"
  OFS=";"
  CONVFMT = "%2.2f"
}
{
  gsub(",",".",$0)
  print $1
  print $2
  print $1+$2
}

$ LC_ALL=fr_BE gawk -f test.awk < file
4.3
5.7
10
4.9
5.7
10.6