Timestamp comparison in awk

awktext processing

Considering below file, how can I compare two timestamps, noting that the time part is negligible.

foo,boo,2038-01-18T12:00:00+02:00
foo,boo,2015-09-12T01:31:24+03:00
foo,boo,2015-08-04T03:15:38+03:00

I tried to make it by substring the date using below code and compare it with other dates i.e: 2015-08-12

awk -F, '{$3=substr($3,1,10)}{if($3<2015-08-12){print $0}}'

But it did not work.

Desired output:

foo,boo,2015-08-04T03:15:38+03:00

OR:

foo,boo,2015-08-04

Best Answer

You need to double quote the date, to force string comparison:

$ awk -F, '$3 < "2015-08-12"' <file
foo,boo,2015-08-04T03:15:38+03:00

Related Solutions

Awk comparison using arrays

I don't see why you would want to do it in a single awk command, what you have seems perfectly fine. Anyway, here's one way:

$ awk -F, '(max[$18]<$21 || max[$18]==""){max[$18]=$21;line[$18]=$0}
            END{for(key in line){print line[key]}}' file
6598,6598,0,1,,1,0,1,1,0,0,0,1,0,0,0,0,1390,1390,,0.730000,
1297,1297,0,0,,0,0,1,0,0,0,0,0,1,0,1,0,1707,1707,,7.000000,
6553,6553,0,1,,1,0,1,1,0,0,0,0,1,0,1,0,4326,4326,,9.000000,

The idea is very simple. We have two arrays, max has $18 as a key and $21 as a value. For every line, if the saved value for $18 is smaller than $21 or if there is no value stored for $18, then we store the current line ($0) as the value for $18 in array line. Finally, in the END{} block, we print array line.

Note that the script above treats $18 as a string. Therefore, 001 and 1 will be considered different strings.

Best Answer

Related Solutions

Awk comparison using arrays

Related Question