NSString转NSData

- (NSData *)hexToBytes:(NSString *)str{NSMutableData* data = [NSMutableData data];int idx;for (idx = 0; idx+2 <= str.length; idx+=2) {    NSRange range = NSMakeRange(idx, 2);    NSString* hexStr = [str substringWithRange:range];    NSScanner* scanner = [NSScanner scannerWithString:hexStr];    unsigned int intValue;    [scanner scanHexInt:&intValue];    [data appendBytes:&intValue length:1];}return data;}//发送数据[self.peripheral writeValue:[self hexToBytes:@"1B9901"] forCharacteristic:self.write type:CBCharacteristicWriteWithoutResponse];

文／勇闯天涯茉莉花茶（简书作者）
原文链接：http://www.jianshu.com/p/a5e25206df39
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