ios 如何检查 NSString = 特定的字符串值？
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how to check if NSString = a specific string value?
提问by C.Johns
Hi I am woundering if you can check to see if a NSString equals a specific value say for instance a name of a person?
嗨，如果你能检查一个 NSString 是否等于一个特定的值，比如一个人的名字，我很伤心？
I am thinking along the lines of
我在思考
if (mystring == @"Johns"){
//do some stuff in here
}
回答by Vanya
if ([mystring isEqualToString:@"Johns"]){
//do some stuff in here
}
回答by Robert
Here is another method you might want to use in some circumstances:
这是您在某些情况下可能想要使用的另一种方法：
NSArray * validNames = @[ @"foo" , @"bar" , @"bob" ];
if ([validNames indexOfObject:myString].location != NSNotFound)
{
// The myString is one of the names in the valid names array
}
Or if you have a large amount of names in the array you could use a NSSet, since finding an object is faster than in an array ((O(Log N)vs O(N))
或者，如果数组中有大量名称，则可以使用 a NSSet，因为查找对象比在数组中更快（(O(Log N)vs O(N)）
NSSet * validNamesSet = [NSSet setWithArray:validNames];
if ([validNamesSet containsObject:myString])
{
// This is faster than indexOfObject for large sets
}
These methods work because NSSetand NSArrayuse isEqual:which will call isEqualToString:for NSStringinstances.
这些方法的工作，因为NSSet和NSArray使用isEqual:，它将调用isEqualToString:的NSString实例。
