Re^2: Problem understanding why for loop won't work when foreach is working

Hello PatGro, and welcome to the Monastery!

I'll read more on closure later today

Start with the FAQ: What's a closure?.
If you have access to the Camel Book¹, you can read about closures in Chapter 8: References.
The Monastery has a tutorial: Closure on Closures.
For in-depth study, Higher-Order Perl (2005) by Mark Jason Dominus is hard to beat. The opening chapters show how closures work-in naturally with other features of Perl to facilitate elegant solutions to common programming problems. The book is available free online at http://hop.perl.plover.com/.

¹Tom Christiansen, brian d foy & Larry Wall with Jon Orwant, Programming Perl, 4^th Edition, 2012.

Hope that helps,

Update: Added author links.

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