Text Manipulation - Increment time/day

nooobeee · 01-23-2018, 07:19 PM

Yep, that did it, but now the date's messed up. Oh well, making progress. I'll take another stab at 'er in the morning.

FYI, if anyone else finds this post, resolution to "function strftime never defined" and "function mktime never defined" on stock ubuntu is the following:

Code:

sudo apt-get install gawk

keefaz · 01-23-2018, 07:19 PM

Quote:

Originally Posted by nooobeee

oh wait, i think i need to install gawk or something like that...i'm pretty sure i had this on my system at work and that's how i addressed it

Yes strftime() and mktime() are in gawk version

nooobeee · 01-23-2018, 07:27 PM

Quote:

Originally Posted by keefaz

Close, but you moved things in wrong places

awk syntax is like: condition {action}
so:

Code:

awk '
BEGIN {FS=OFS=",";timestamp=mktime("2017 01 01 00 00 00")}
$1!=u {hour=1;u=$1}
{print $1, strftime("%D %R", timestamp + hour++ * 60 * 60),$2, $3}
' input.csv

BEGIN{}: initialize block
$1 != u: condition
if condtion is true then next block: {hour=1;u=$1}
and following block is executed without condition

I'm not sure i understand the hour=1 part. Is that the part that resets the timestamp? If so, i don't see how.

nooobeee · 01-23-2018, 07:29 PM

BTW, that code did work, but I'd like to understand that part about hour=1. Is that a function of mktime and strftime?

keefaz · 01-23-2018, 08:09 PM

No that resets the hour counter, hour is just a variable (any name will do)

see gawk time function
https://www.gnu.org/software/gawk/ma...Functions.html

mktime creates a timestamp, eg a number in seconds from Unix epoch (1970 00:00:00 GMT)
1 hour is 60 * 60 seconds, so with hour = 1:
timestamp + hour++ * 60 * 60 => added 1 hour to timestamp value and hour is incremented by 1 after the operation (hour++, hour = 2)

Edit: timestamp is never reseted, it has the same value during all the program execution

nooobeee · 01-23-2018, 08:17 PM

Ahhh, ok, that makes sense of the *60*60. Thanks for the link and explanation...i'll do some more reading and test this out in my sandbox tomorrow and report back. Thanks for all your help.