1.求字符串長度
NSUInteger length = [str1 length];
NSLog(@"length = %lu", length);
2.獲取字符串中的某個字符
unichar charac = [str1 characterAtIndex:6];
NSLog(@"%c", charac);
3.判斷是否以指定的字符串開頭或者以指定的字符串結尾
例如:判斷一個字符串是否以http平開頭
NSString *str4 = [[NSStringalloc] initWithFormat:@"http://www.souhu.com"];
判斷是否以http開頭
BOOL isPrefix = [str4hasPrefix:@"http"];
NSLog(@"isPrefix = %d", isPrefix);
判斷是否以.com結尾
BOOL isSuffix = [str4hasSuffix:@"com"];
NSLog(@"isSuffix = %d", isSuffix);
查找指定字符串的範圍
NSRange range = [str4rangeOfString:@"com"];
結構體成員通過.成員訪問
if (range.length ==0) {
NSLog(@"沒有呀找到");
}else{
NSLog(@"location:%lu,length:%lu", range.location, range.length);
NSLog(@"%@",NSStringFromRange(range));
}
4.字符串的截取
獲取給定下標之後後的字串,包含指定下標對應的字符.
NSString *str5 =[NSString stringWithFormat:@"lanouisabigcompany"];
NSString *subString1 = [str5 substringFromIndex:5];
NSLog(@"%@", subString1);
獲取給定下標之前的子串,從下標爲0開始,但是不包括指定下標對應的字符.
NSString *substring2 = [str5 substringToIndex:1];
NSLog(@"%@", substring2);
獲取指定範圍內的子串.
NSRange
NSString * substring3 = [str5 substringWithRange:NSMakeRange(0, 5)];
NSLog(@"%@", substring3);
5.字符串拼接
NSString *str1 = [NSString stringWithFormat:@"lanou"];
p拼接"hennan"
NSString *substring1 = [str1 stringByAppendingString:@"henan"];
NSLog(@"substring = %@", substring1);
拼接"henan9ban"
stringByAppendingFormat可以添加格式
NSString *substring2 = [str1 stringByAppendingFormat:@"henan%dban", 9];
NSLog(@"sunstring2 = %@", substring2);
NSString *substring3 = [str1 stringByAppendingFormat:@"%@", str1];
NSLog(@"sunstring3 = %@", substring3);
6. 替換字符串
將ou替換爲牛逼
NSString *str1 = [NSString stringWithFormat:@"lanououououoooo"];
NSString *str = [str1 stringByReplacingOccurrencesOfString:@"ou" withString:@"牛逼"];
NSLog(@"str1 = %@", str);
將第一個ou替換爲牛逼
NSMakeRange快速創建一個結構體
NSString *strr = [str1 stringByReplacingCharactersInRange:NSMakeRange(3, 2) withString:@"牛逼"];
NSLog(@"strr = %@", strr);
7. 字符串比較(重點)
NSComparisonResult result = [@"311"compare:@"311"];
NSLog(@"result = %ld", result);
8. 字符串與數值類型轉換
將123轉換爲整數123.
從第一個字符開始,如果在遇到除空格之外的字符時,將齊安民的空格忽略掉,繼續往下找,直到遇到非數字時結束
int value = [@"1a23bbb" intValue];
NSLog(@"%d", value);