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Programming-Idioms

History of Idiom 51 > diff from v16 to v17

Edit summary for version 17 by :

Version 16

2015-09-04, 18:21:49

Version 17

2015-09-04, 18:25:14

Idiom #51 Check if map contains key

Determine whether map m contains an entry for key k

Idiom #51 Check if map contains key

Determine whether map m contains an entry for key k

Code
lookup k m /= Nothing
Code
(/=Nothing) (lookup k m)