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math.h 函数说明一览 - C/C++ - 清泛网 - 专注C/C++及内核技术
...数说明acos()求反余弦的值cos()求余弦值cosh()求双曲余玄值exp()e的次幂函数(以e为底的x次方值)frexp()把一个浮点数分解为尾数和指数ldex...
函数
说明
acos()
求反余弦的值
cos()
求余弦值
cosh()
求双曲...
xxx.sh: line x: [0: command not found - 更多技术 - 清泛网 - 专注C/C++及内核技术
xxx.sh: line x: [0: command not found由于if [后面没有加空格导致的。if [ xxx ] 表达式前后都要有空格。由于if [ 后面没有加空格导致的。
if [ xxx ] 表达式前后都要有空格。command not found
Discuz X 首页白板解决之道 - 更多技术 - 清泛网 - 专注C/C++及内核技术
Discuz X 首页白板解决之道1、开启Debug，及url后面跟 &debug=yes，也是网上最多的方法，但可能往往没有效果。2、排除法，代码一段段的排查，在合适位置打印特定内容然后exit(0);查看结果，分析出现问题的 1、开启Debug，及url后面...
【解决】php7.x后报错Warning: Use of undefined constant PRE - assumed问...
【解决】php7.x后报错Warning: Use of undefined constant PRE - assumed问题解决此种问题其实也不是很难，只是报了Warning警告，我们只需要关闭PHP错误提示就行了。具体步骤如下：1、打开 php ini2、设置 error_reporting = E_ALL & ~E_DEPRECATED & 解决...
Scraping html tables into R data frames using the XML package
How do I scrape html tables using the XML package?
4 Answers
4
...
What is the purpose of a stack? Why do we need it?
...IT (Just In Time) compiler turns the IL into actual machine code that can execute.
So first let's answer the question "why have MSIL at all?" Why not just have the C# compiler write out machine code?
Because it is cheaper to do it this way. Suppose we didn't do it that way; suppose each language...
Return two and more values from a method
...
def sumdiff(x, y)
return x+y, x-y
end
#=> nil
sumdiff(3, 4)
#=> [7, -1]
a = sumdiff(3,4)
#=> [7, -1]
a
#=> [7, -1]
a,b=sumdiff(3,4)
#=> [7, -1]
a
#=> 7
b
#=> -1
a,b,c=sumdiff(3,4)
#=> [7, -1]
a
#=> 7
b
#=...
Are arrays in PHP copied as value or as reference to new variables, and when passed to functions?
...e the reference operator to
copy an array by reference.
And the given example :
<?php
$arr1 = array(2, 3);
$arr2 = $arr1;
$arr2[] = 4; // $arr2 is changed,
// $arr1 is still array(2, 3)
$arr3 = &$arr1;
$arr3[] = 4; // now $arr1 and $arr3 are the same
?>
For the first ...
Is there a “theirs” version of “git merge -s ours”?
...
Add the -X option to theirs. For example:
git checkout branchA
git merge -X theirs branchB
Everything will merge in the desired way.
The only thing I've seen cause problems is if files were deleted from branchB. They show up as co...
warning about too many open figures
In a script where I create many figures with fix, ax = plt.subplots(...) , I get the warning RuntimeWarning: More than 20 figures have been opened. Figures created through the pyplot interface (matplotlib.pyplot.figure) are retained until explicitly closed and may consume too much memory.
...