# scanLines -- apply a function to each line of a file

## Synopsis

• Usage:
scanLines(f,fn)
• Inputs:
• f
• fn, the name of a file, or a list of names of files
• Outputs:
• returns null unless the function uses break x with a non-null value for x, in which case scanning stops and x is returned immediately
• Consequences:
• applies f to each line of the file(s)

## Description

The file is read and processed one block at a time, making this procedure potentially much better at conserving memory than scan(lines get fn,f) when the file is very large.

## Ways to use scanLines :

• "scanLines(Function,List)"
• "scanLines(Function,String)"

## For the programmer

The object scanLines is .