You've just found out that =~ is not a symmetrical relation, while == is. Other asymmetrical relations are <, >, <=, >=. Other symmetrical relations are != and eq. If you want to learn more on (symmetric) relations, see Symmetric relation.

Would it surprise you if a program that used $a < $b had output different from an otherwise identical program that used $b < $a?

In reply to Re: same program different output by Corion
in thread same program different output by jesuashok

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