Re^3: MCE: How to access variables globally

If all you need is a count of the number of iterations, and the keys are unique, you can use something as simple as:

$ perl -E 'my %x = (a=>1, b=>2, c=>3); say "Count: ", 0+keys(%x)'
Count: 3
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If the situation is more complex than that — non-unique keys; lines skipped for some reason; and so on — you'll need to provide more information or I'm only guessing (and I don't really want to waste time doing that). You should show some sample input: keep it short but still realistic with example exception cases. Then show the expected output from that input.

If duplicate keys are encountered, should they be skipped or should their value overwrite the previous value. Other reasons that lines might be skipped are: they're blank, are comments, don't match /^\S+\s+\S+$/, or something else. What else is special that I should know about?

When I saw your OP code, I thought the first (non-MCE) loop, and the two counters, were just for testing. Clearly, that was a poor guess; please help me out here.

— Ken

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Re^4: MCE: How to access variables globally by biohisham (Priest) on Dec 20, 2021 at 07:15 UTC
Thanks a lot Ken for your help; your guess is on-spot. The keys reflect States that do repeat in different lines/cols and associated with them prob and errorProb values against a time stamp. So the idea is to turn the states into columns of `state name\tProb[state]\t Error[state]`and align them against the time. The original file is generated by a mathematical modelling (Boolean modelling of networks) software and requires changing its format to be able to do further analysis. Its a large file hence I split it and I am reading it in chunks to avoid the OOM killer. The header looks like this `Time TH ErrorTH H HD=0 State Proba ErrorProba +State Proba ErrorProba State State Proba ErrorProba` [download] Here is how my minimum working example looks like Read more... (57 kB) Something or the other, a monk since 2009	[reply] [d/l] [select]
Re^5: MCE: How to access variables globally by marioroy (Prior) on Dec 20, 2021 at 10:51 UTC
Greetings, biohisham, Gathering nested data is possible with a gather callback. MCE::Relay is used to relay the index line counter. I commented out the section regarding past index line. Starting from 0 each time made me wonder. I changed it to relay index line. Please note that $ret_FullGlobal, $ret_ProbState, and $ret_ErrProbState hashes are HoH-H and HoH. Important! Remember to "not" gather HoH->A and HoA structures containing "only" high indexes. Perl is likely to reserve memory for the empty array slots. For your use case, HoH-H and HoH are your friends with regards to gathering nested structure. The gather callback can then append/populate the global HoH->A and HoA structures. Read more... (6 kB)	[reply] [d/l]
Re^5: MCE: How to access variables globally by kcott (Archbishop) on Dec 20, 2021 at 08:40 UTC
"Thanks a lot Ken for your help; your guess is on-spot." OK, that's great. Now that I see you're working with CSV data, one further piece of advice: take a look at Text::CSV (and note that if you also have Text::CSV_XS installed, it will run faster). — Ken	[reply]