byte

问题 I have a byte in variable 'DATA'. I want to extract the LSB bit out of it and print it. I'm very new to python, I found many articles with complex bitwise addition logic and all which was very tough to understand. I'm looking for a simple logic like we do with the strings eg DATA[7:1] Please help me out... 回答1: Is your "byte" an int ? If so, just take bitwise AND ( & ) with 1 (or, if you want to be more explicit, the binary literal 0b1 ) to get the least significant bit. >>> x = 14 >>> x & 1

问题 I'm wondering if there is a simple, built-in function in Python / Numpy for converting an integer datatype to an array/list of booleans, corresponding to a bitwise interpretation of the number please? e.g: x = 5 # i.e. 101 in binary print FUNCTION(x) and then I'd like returned: [True, False, True] or ideally, with padding to always return 8 boolean values (i.e. one full byte): [False, False, False, False, False, True, False, True] Thanks 回答1: You can use numpy's unpackbits . From the docs

问题 This question already has answers here : Closed 7 years ago . Possible Duplicate: When does Endianness become a factor? reading this tuto on endianess, i fall on this example where endianess does matter. It is about writting a char* filled with 1 and 0. it can then be converted to a short, and results depends on endianess, little or big. Here is the example, quoted. unsigned char endian[2] = {1, 0}; short x; x = *(short *) endian; What would be the value of x? Let's look at what this code is

问题 Ok, before anyone attempts to label this as a duplicate, I am not asking for a string to a byte array. I want a string array, containing something similar like this: {"5","168","188","28","29","155"} to be converted to a byte array. I have searched, and was only able to find string to byte array, which is quite different. Thanks. Edit: the array will be preset so that each member is parsable through byte.Parse, so this is not an issue. 回答1: This will fail for anything that can't be parsed by

问题 Both return the same pointer. I know - bytes belongs to NSData , why does NSMutableData introduce - mutableBytes ? Is it just for code clarity so it is more obvious you are accessing mutable data? Does it really matter which one is used? NSMutableData* mydata = [[NSMutableData alloc] init]; [mydata appendData: [@"hello" dataUsingEncoding:NSUTF8StringEncoding]]; NSLog(@"%p", [mydata mutableBytes]); NSLog(@"%p", [mydata bytes]); Thanks. 回答1: There are a couple of reasons why NSMutableData might

问题 In http://www.parashift.com/c++-faq-lite/intrinsic-types.html#faq-26.6, it is wriiten that "Another valid approach would be to define a "byte" as 9 bits, and simulate a char* by two words of memory: the first could point to the 36-bit word, the second could be a bit-offset within that word. In that case, the C++ compiler would need to add extra instructions when compiling code using char* pointers." I couldn't understand what it meant by "simulating char* by two words" and further quote.

问题 There is a .jpg file for example or some other file. I want to read it bit by bit. I do this: open(FH, "<", "red.jpg") or die "Error: $!\n"; my $str; while(<FH>) { $str .= unpack('B*', $_); } close FH; Well it gives me $str with 0101001 of the file. After that I do this: open(AB, ">", "new.jpg") or die "Error: $!\n"; binmode(AB); print AB $str; close AB; but it doesn't work. How can I do it? and how to do that that it would work regardless of byte order(cross-platform)? 回答1: Problems: You're

问题 I have the following buffer byte pingBuff[] ={0x01, 0x01,0x00,0x01,0x00,0x20} I need to calculate 16 bit CRC of these 6 bytes and append it at the end of the pingBuff[] I have done it using C++ and tried to change that code in java like below but it didnot work. package org.totalbeginner.tutorial; public class CRCLikeC { /* Table of CRC values for high–order byte */ char auchCRCHi[] = { 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0, 0x80, 0x41, 0x01, 0xC0, 0x80, 0x41, 0x00, 0xC1, 0x81, 0x40, 0x01, 0xC0,

问题 Say I've got an integer, 13941412, that I wish to separate into bytes (the number is actually a color in the form 0x00bbggrr). How would you do that? In c, you'd cast the number to a BYTE and then shift the bits. How do you cast to byte in Python? 回答1: Use bitwise mathematical operators, the "bytes" are already there: def int_to_rgb(n): b = (n & 0xff0000) >> 16 g = (n & 0x00ff00) >> 8 r = (n & 0x0000ff) return (r, g, b) 回答2: You can bitwise & with 0xff to get the first byte, then shift 8 bits

问题 I have a database in MYSQL Server. There's a table store an Image with its info. That image's data type is Mediumblob. I need to read it and store in a byte[] but I don't know how to do that.Anyone have a solution for this case? Tks so much :) Regards. 回答1: Looking at the examples from this article on MySQL website, you should be able to handle the data like this: To store the image: MySql.Data.MySqlClient.MySqlConnection conn; MySql.Data.MySqlClient.MySqlCommand cmd; // initialize "conn" and