這篇主要對(duì)字符串之間的比較做個(gè)簡(jiǎn)單總結(jié)
NSString 兩個(gè)字符串的比較自阱，用 a compare:b 來(lái)比噪服，得出的結(jié)果分3種
1. 26個(gè)字母比較 越靠后面越大
NSString *a = @"abcabc";
NSString *b = @"abcabd";
BOOL result = [a compare:b];
if (result == NSOrderedSame) {
// NSOrderedSame = 0 完全一樣
NSLog(@"a = b");
}else if(result == NSOrderedAscending)
// NSOrderedAscending = -1 遞增
NSLog(@"a < b");
else{
//NSOrderedDescending = +1 遞減
NSLog(@"a > b");
}
2.比較數(shù)字或者符號(hào)，或者字母 什么都行
NSString *a = @"20160809abc";
NSString *b = @"20160809abd";
BOOL result = [a compare:b];
if (result == NSOrderedSame) {
// NSOrderedSame = 0 完全一樣
NSLog(@"a = b");
}else if(result == NSOrderedAscending)
// NSOrderedAscending = -1
NSLog(@"a < b");
else{
//NSOrderedDescending = +1
NSLog(@"a > b");
}
3.不考慮大小寫比較字符串
[a caseInsensitiveCompare:b]
- (void)viewDidLoad
{
NSString *a = @"i love my girlfriend.";
NSString *b = @"I Love My Girlfriend.";
NSLog(@" \n a: %@ \n",a);
NSLog(@" \n b: %@ \n",a);
BOOL result = [a caseInsensitiveCompare:b] == NSOrderedSame;
｝
//result = (BOOL) YES;
4.不考慮大小寫比較字符串
[a caseInsensitiveCompare:b]
- (void)viewDidLoad
{
NSString *a = @"i love my boyfriend.";
NSString *b = @"Little baby.";
NSLog(@" \n a: %@ \n",a);
NSLog(@" \n b: %@ \n",a);
BOOL result = [a caseInsensitiveCompare:b] == NSOrderedAscending;
}
//result = (BOOL) YES;
5. 有選擇的比較大小 [a compare:b options:NSCaseInsensitiveSearch|NSNumericSearch]
- (void)viewDidLoad
{
NSString *a = @"i love my boyfriend.";
NSString *b = @"I Love My Boyfriend.";
NSLog(@" \n a: %@ \n",a);
NSLog(@" \n b: %@ \n",b);
BOOL result = [a compare:b options:NSCaseInsensitiveSearch|NSNumericSearch] == NSOrderedSame;
}
//result = (BOOL)YES;
NSCaseInsensitiveSearch 忽略大小寫的比較字符串
NSNumericSearch 比較字符串的個(gè)數(shù)
NSLiteralSearch 區(qū)分大小寫，進(jìn)行完全比較
