我如何检查一个字符串(NSString)包含另一个较小的字符串?
我希望是这样的:
NSString *string = @"hello bla bla";
NSLog(@"%d",[string containsSubstring:@"hello"]);
但我能找到的最接近的是:
if ([string rangeOfString:@"hello"] == 0) {
NSLog(@"sub string doesnt exist");
}
else {
NSLog(@"exists");
}
不管怎样，这是找出字符串是否包含另一个字符串的最好方法吗?
当前回答
试试这个:
Swift 4.1、4.2:
let stringData = "Black board"
//swift quick way and case sensitive
if stringData.contains("bla") {
print("data contains string");
}
//case sensitive
if stringData.range(of: "bla",options: .caseInsensitive) != nil {
print("data contains string");
}else {
print("data does not contains string");
}
objective - c:
NSString *stringData = @"Black board";
//Quick way and case sensitive
if ([stringData containsString:@"bla"]) {
NSLog(@"data contains string");
}
//Case Insensitive
if ([stringData rangeOfString:@"bla" options:NSCaseInsensitiveSearch].location != NSNotFound) {
NSLog(@"data contains string");
}else {
NSLog(@"data does not contain string");
}
其他回答
NSString *categoryString = @"Holiday Event";
if([categoryString rangeOfString:@"Holiday"].location == NSNotFound)
{
//categoryString does not contains Holiday
}
else
{
//categoryString contains Holiday
}
第一串是否包含第二串，
NSString *first = @"Banana";
NSString *second = @"BananaMilk";
NSRange range = [first rangeOfString:second options:NSCaseInsensitiveSearch];
if (range.length > 0) {
NSLog(@"Detected");
}
else {
NSLog(@"Not detected");
}
所以我个人非常讨厌NSNotFound，但是理解它的必要性。
但是有些人可能不理解与NSNotFound比较的复杂性
例如，下面的代码:
- (BOOL)doesString:(NSString*)string containString:(NSString*)otherString {
if([string rangeOfString:otherString].location != NSNotFound)
return YES;
else
return NO;
}
有它的问题:
1)显然，如果otherString = nil这段代码将崩溃。一个简单的测试是:
NSLog(@"does string contain string - %@", [self doesString:@"hey" containString:nil] ? @"YES": @"NO");
结果!!崩溃! !
2)对于objective-c的新手来说，不太明显的是，当string = nil时，相同的代码不会崩溃。 例如，下面的代码:
NSLog(@"does string contain string - %@", [self doesString:nil containString:@"hey"] ? @"YES": @"NO");
这段代码:
NSLog(@"does string contain string - %@", [self doesString:nil containString:nil] ? @"YES": @"NO");
都会导致
does string contains string - YES
这显然不是你想要的。
所以我认为更好的解决方案是使用rangeOfString返回0的长度，然后一个更好更可靠的代码是这样的:
- (BOOL)doesString:(NSString*)string containString:(NSString*)otherString {
if(otherString && [string rangeOfString:otherString].length)
return YES;
else
return NO;
}
或者仅仅是:
- (BOOL)doesString:(NSString*)string containString:(NSString*)otherString {
return (otherString && [string rangeOfString:otherString].length);
}
对于情况1和2哪种会返回
does string contains string - NO
这是我的2美分;-)
请查看我的Gist以获得更多有用的代码。
在iOS 8和Swift中，我们可以使用localizedCaseInsensitiveContainsString方法
let string: NSString = "Café"
let substring: NSString = "É"
string.localizedCaseInsensitiveContainsString(substring) // true
在Swift 4中:
let a = "Hello, how are you?"
a.contains("Hello") //will return true
