objective-c - 目标 C：确定 NSString 中是否存在子字符串的最简单方法是什么？

Question

在 PHP（这是我最熟悉的）中，它是一个单行表达式：

strpos('abc', 'b') !== false

Objective C 的等价物是什么？

Answer 1

[@"abc" rangeOfString:@"b"].location != NSNotFound

Answer 2

I think categories can be use to package up pieces of functionality like this very nicely.

@interface NSString (ContainsString)
- (BOOL)containsString:(NSString *)string;
@end

@implementation NSString (ContainsString)
- (BOOL)containsString:(NSString *)string
{
    NSRange range = [self rangeOfString:string options:NSCaseInsensitiveSearch];
    return range.location != NSNotFound;
}
@end

When used, it makes the meaning very clear.

if ([@"this is a string" containsString:@"a string"]) {
    …
}

In most projects this would be a part of a larger string method category and not it's own one-method category.

Answer 3

- (NSRange)rangeOfString:(NSString *)aString

返回值 一个 NSRange 结构，给出第一次出现的 aString 在接收器中的位置和长度。如果 aString 未找到或为空 (@"")，则返回 {NSNotFound, 0}。

您可以在NSString 类参考中找到更多有用的字符串操作函数