NSString 字符串的截取和替换

-(void)test{
NSString *testStr=@"abcdefg";
//从字符串的指定位置2截取到字符串末尾
NSString *new1=[testStr substringFromIndex:2];
NSLog(@"**********new1 = %@",new1);
//从字符串开头截取到字符串3的指定位置
NSString *new2=[testStr substringToIndex:3];
NSLog(@"**********new2 = %@",new2);
//从字符串的指定位置1截取到指定长度3
NSRange range={1,3};
//NSRange range=NSMakeRange(1, 3);
NSString *new3=[testStr substringWithRange:range];
NSLog(@"**********new3 = %@",new3);
//将abcdefg中的abc替换为123
testStr=[testStr stringByReplacingOccurrencesOfString:@"abc" withString:@"123"];
NSLog(@"**********newStr = %@",testStr);
//待处理的字符串
NSString *string = @" A B CD EFG\n MN\n";
//字符串替换，处理后的string1 ＝ @"ABCDEF\nMN\n";
NSString *string1 = [string stringByReplacingOccurrencesOfString:@" " withString:@""];
//去除两端空格(注意是两端),处理后的string2 ＝ @"A B CD EFG\n MN\n";
NSString *string2 = [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceCharacterSet]];
//去除两端回车(注意是两端),处理后的string3 ＝ @" A B CD EFG\n MN";
NSString *string3 = [string stringByTrimmingCharactersInSet:[NSCharacterSet newlineCharacterSet]];
//去除两端空格和回车(注意是两端),处理后的string4 ＝ @"A B CD EFG\n MN";
NSString *string4 = [string stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];

}