[英]What is the difference between if(!variable) and if(variable != nil) iphone
到底有什么區別
if(!variable)
do something
和
if(variable != nil)
do something
如前所述，您的邏輯有點倒退，但除此之外，它們的工作方式相同。
要考慮的主要事情是( variable != nil )更清楚您正在檢查的內容以及變量的類型，因為有人可能會開始認為該變量是 boolean。
它們完全相同：
if ( !var )等價於if ( var != nil )
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