Delta from the first digit

Shell Programming and Scripting
1

Thanks of your suggestions i was able to calculate the delta between some numbers in a column file with .

 awk 'BEGIN{last=0}{delta[NR]=$1-last; last=$1; print $0" "delta[NR]}'

the file was like

499849120.00
500201312.00
500352416.00
500402784.00
500150944.00
499849120.00
500150944.00
500453184.00
499949664.00
500050304.00
500100640.00

but what if i want to use the first element of this list and create the delta between the first element on the list and all the others?

Thanks in advance.

Best regards

2

Use NR == 1 for the last assignent, and don't modify it any more.

3

Thanks for your answer.

i've tried with

awk 'BEGIN{last=NR == 1}{delta[NR]=$1-last; last=$1; print $0" "delta[NR]}' filename

but still create same output with delta by each line

and with

awk 'BEGIN{NR == 1}{delta[NR]=$1-last; last=NR == 1; print $0" "delta[NR]}'

it just delete the last .00 decimals

4

Try (untested)

awk 'NR == 1 {last = $1} {print $0, $1 - last}'

If a value is an exact integer, awk strips decimals by default. Use printf in case you want decimals.

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