Question

I would like your help, because I am not able to understand what the following line means:

map {@$_[1 .. 4]} @msft

found in the example code of GD::Graph::ohlc.
Could you please provide me with a hint?

Thank you.

Answer 1

@msft is an array of arrays where each inner array contains 5 items (date, open/low/high/close prices).

The map takes each element of @msft, which is an array reference stored in $_ and dereferences it via @$_ and takes a slice of that array (namely the second through fifth items since the array is 0-based) via the [1..4]. It then returns those four items. map concatenates them into a single list.

In essence, it is flattening the array of arrays of five elements into a single array made up of the 2nd through 5th items of each subarray.