1.NSString to NSData
NSString* str= @"teststring";
NSData* data = [str dataUsingEncoding:NSUTF8StringEncoding];
NSData* data = [NSData dataWithBytes:[str UTF8String] length:strlen([str UTF8String])];
NSString* newStr = [[NSString alloc] initWithData:theData
encoding:NSUTF8StringEncoding];
NSString* newStr = [NSString stringWithUTF8String:[theData bytes]];
NSString *unicodeStr = [NSString stringWithCString:[utf8Str UTF8String] encoding:NSUnicodeStringEncoding];
4.NSString trim
NSString* str = [NSString stringWithString:@" \n abcd xyz \n"];
NSString* str2 = [str stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];
NSLog(@"%@ %@ %u",str,str2 , [str2 length]);
stringByTrimmingCharactersInSet 只是trim头尾的空格和换行,不能trim中间的空格。
过滤中间包括的空格:
NSString* str = [NSString stringWithString:@" \n abcd \n"];
str = [str stringByReplacingOccurrencesOfString:@" " withString:@""];