如何检查 NSString = 特定字符串值？

发布于 2024-12-02 13:19:44 字数 143 浏览 0 评论 0 原文

您好，如果您可以检查 NSString 是否等于特定值（例如人名），我很受伤？

我正在思考

if (mystring == @"Johns"){
    //do some stuff in here
}

原文

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?

I am thinking along the lines of

if (mystring == @"Johns"){
    //do some stuff in here
}

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罪歌 2024-12-09 13:19:44

if ([mystring isEqualToString:@"Johns"]){
    //do some stuff in here
}

if ([mystring isEqualToString:@"Johns"]){
    //do some stuff in here
}

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撩心不撩汉 2024-12-09 13:19:44

在某些情况下，您可能需要使用以下另一种方法：

NSArray * validNames = @[ @"foo" , @"bar" , @"bob" ];

if ([validNames indexOfObject:myString].location != NSNotFound) 
{
    // The myString is one of the names in the valid names array
}

或者，如果数组中有大量名称，您可以使用 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
}

这些方法之所以有效，是因为 NSSet 和 NSArray 使用 isEqual: 它将调用 isEqualToString: 用于 NSString 实例。

Here is another method you might want to use in some circumstances:

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))

NSSet * validNamesSet = [NSSet setWithArray:validNames];

if ([validNamesSet containsObject:myString]) 
{
    // This is faster than indexOfObject for large sets
}

These methods work because NSSet and NSArray use isEqual: which will call isEqualToString: for NSString instances.