BOOL result = [first compare:sencond] == NSOrderedSame;
NSLog(@"result:%d",result);
打印结果：
result:0
复制代码
BOOL result = [first compare:second] == NSOrderedAscending;
NSLog(@"result:%d",result);
打印结果：
result:0
复制代码
BOOL result = [first compare:second] == NSOrderedDecending; NSLog(@"result:%d",result);
打印结果：
result:1
3、不考虑大小写比较字符串
复制代码BOOL result = [first compare:second
options:NSCaseInsensitiveSearch | NSNumericSearch] == NSOrderedSame;
NSLog(@"result:%d",result);
打印结果：
result:1
五、改变字符串大小写
复制代码NSString *aString = @"A String";
NSString *string = @"String";
//大写
NSLog(@"aString:%@",[aString uppercaseString]);
//小写
NSLog(@"string:%@",[string lowercaseString]);
//首字母大小写
NSLog(@"string:%@",[string capitalizedString]);
打印结果：
aString:A STRING
string:string
string:String
六、在字符串中搜索子串
复制代码NSString *string1 = @"This is a string";
NSString *string2 = @"string";
NSRange range = [string1 rangeOfString:string2];
NSUInteger location = range.location;
NSUInteger leight = range.length;
