Use if let syntax for groupBy and countBy
Use if let syntax for groupBy and countBy

This uses more idiomatic if let syntax to bind the optional dictionary lookup if it succeeds.
Unused array variable removed from groupBy.

brandenr/ExSwift,sagesse-cn/ExSwift,burhanaksendir/ExSwift,mikekavouras/ExSwift,natecook1000/ExSwift,hasankose/ExSwift,Jinxiaoming/ExSwift,msdgwzhy6/ExSwift,Ravichandrane/ExSwift,hasankose/ExSwift,LiuDeng/ExSwift,ktonon/ExSwift,luzefeng/ExSwift,sagesse-cn/ExSwift,luzefeng/ExSwift,frankenthumbs/ExSwift,jalehman/ExSwift,chrux/ExSwift,henriquevelloso/ExSwift,vittoriom/ExSwift,jalehman/ExSwift,burhanaksendir/ExSwift,pNre/ExSwift,pNre/ExSwift,apouche/ExSwift,kostiakoval/ExSwift,apouche/ExSwift,LiuDeng/ExSwift,Natoto/ExSwift,luzefeng/ExSwift,mikekavouras/ExSwift,gpongelli/ExSwift,vittoriom/ExSwift,marinehero/ExSwift,kostiakoval/ExSwift,marinehero/ExSwift,RajkumarPunchh/ExSwift,natecook1000/ExSwift,zhuqling/ExSwift,mikekavouras/ExSwift,sagesse-cn/ExSwift,apouche/ExSwift,sebbean/ExSwift,burhanaksendir/ExSwift,Ravichandrane/ExSwift,Natoto/ExSwift,msdgwzhy6/ExSwift,brandenr/ExSwift,Ravichandrane/ExSwift,vittoriom/ExSwift,Jinxiaoming/ExSwift,msdgwzhy6/ExSwift,henriquevelloso/ExSwift,brandenr/ExSwift,iosyoujian/ExSwift,gpongelli/ExSwift,LiuDeng/ExSwift,ktonon/ExSwift,yariksmirnov/ExSwift,Natoto/ExSwift,hasankose/ExSwift,katopz/ExSwift,gpongelli/ExSwift,RajkumarPunchh/ExSwift,natecook1000/ExSwift,zhuqling/ExSwift,jalehman/ExSwift,pNre/ExSwift,henriquevelloso/ExSwift,iosyoujian/ExSwift,marinehero/ExSwift,kostiakoval/ExSwift,iosyoujian/ExSwift,chrux/ExSwift,sebbean/ExSwift,yariksmirnov/ExSwift,katopz/ExSwift,frankenthumbs/ExSwift