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How to remove last n characters from every element in the R vector
...
Note: This returns the original string if it is longer then number of characters to cut. Consider gsub('.{5}$', '', 'abcd').
– Tomas Greif
Jan 17 '15 at 7:08
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逆向工程——二进制炸弹(CSAPP Project) - 操作系统(内核) - 清泛网 - 专注...
...这六个关卡了。
===============phase_1===============
知识点：string，函数调用，栈
用了差不多一个星期断断续续地寻找感觉的phase_1，最主要不知道从何入手。虽然phase_1也不过10+行指令，但最初我的出发点错了：完全依靠人工去读...
PHP: Convert any string to UTF-8 without knowing the original character set, or at least try
...t mb_detect_encoding source code in your php distro (somewhere here: ext/mbstring/libmbfl/mbfl/mbfl_ident.c). This function does not work properly at all. For some encodings it even has "return true", lol. Others are in Ctrl+c Ctrl+v functions. That's because you can not detect encoding without some...
C Macro definition to determine big endian or little endian machine?
...define ORDER32_H
#include <limits.h>
#include <stdint.h>
#if CHAR_BIT != 8
#error "unsupported char size"
#endif
enum
{
O32_LITTLE_ENDIAN = 0x03020100ul,
O32_BIG_ENDIAN = 0x00010203ul,
O32_PDP_ENDIAN = 0x01000302ul, /* DEC PDP-11 (aka ENDIAN_LITTLE_WORD) */
O32_HO...
No visible cause for “Unexpected token ILLEGAL”
...rs. It seems the tool uses that character to control word-wrapping on long strings.
UPDATE 2013-01-07
After the latest jsfiddle update, it's now showing the character as a red dot like codepen does. Apparently, it's also not inserting U+200B characters on its own anymore, so this problem should be ...
PostgreSQL Crosstab Query
... the provided input query: row_name, category, value. There is no room for extra columns like in the 2-parameter alternative below.
Safe form
crosstab(text, text) with 2 input parameters:
SELECT *
FROM crosstab(
'SELECT section, status, ct
FROM tbl
ORDER BY 1,2' -- could also ju...
Iterating each character in a string using Python
In C++, I can iterate over an std::string like this:
8 Answers
8
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json_encode is returning NULL?
...e at least PHP 5.5, you can use json_last_error_msg(), which will return a string describing the problem.
If you don't have 5.5, but are on/above 5.3, you can use json_last_error() to see what the problem is.
It will return an integer, that you can use to identify the problem in the function's doc...
Writing a compiler in its own language
... assembler. Eventually, you will come to the place where you have to parse strings, specifically escape sequences. You will write code to convert \n to the character with the decimal code 10 (and \r to 13, etc).
After that compiler is ready, you will start to reimplement it in C. This process is ca...
What is the point of function pointers?
...orithm, but also data:
class functor {
public:
functor(const std::string& prompt) : prompt_(prompt) {}
void operator()(int i) {std::cout << prompt_ << i << '\n';}
private:
std::string prompt_;
};
functor f("the answer is: ");
f(42);
Another advantage is ...