wendy24,
Assuming by field, you mean that the data is delimited in some way - see Text::CSV_XS or Text::xSV. Additionally, DBD::CSV may make the task even easier depending on your situation. If your fields are fixed width then perhaps you want unpack.

In a nutshell, you have not provided enough information for us to help you. In general, you want to read the records in examining the field that dictates the new value of the other field, perform your calculation, and then write the record out to a new file in sequence. The above paragraph provides suggestions on how you might accomplish that.

Cheers - L~R

In reply to Re: Updating fields in a text file by Limbic~Region
in thread Updating fields in a text file by wendy24

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