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How can I print the contents of a hash in Perl?
... your friend.
use Data::Dumper;
my %hash = ('abc' => 123, 'def' => [4,5,6]);
print Dumper(\%hash);
will output
$VAR1 = {
'def' => [
4,
5,
6
],
'abc' => 123
};
...
Why is Multiple Inheritance not allowed in Java or C#?
...
143
The short answer is: because the language designers decided not to.
Basically, it seemed that ...
How to sum a variable by group
...
404
Using aggregate:
aggregate(x$Frequency, by=list(Category=x$Category), FUN=sum)
Category x
...
实战Nginx与PHP（FastCGI）的安装、配置与优化 - 更多技术 - 清泛网 - 专注...
...这里为了介绍PHP的FastCGI功能没有加入更多的编译选项。
4.配置与优化PHP-FPM
PHP的全局配置文件是php.ini，在上面的步骤中，已经将此文件复制到了/usr/local/php/lib/php.ini下。可以根据每个应用需求的不同，对php.ini进行相应的配置。...
'echo' without newline in a shell script
...
answered Jun 25 '12 at 16:42
Keith ThompsonKeith Thompson
221k3333 gold badges352352 silver badges557557 bronze badges
...
NSIS做的安装程序，可接受命令行参数，实现静默安装，静默卸载 - 更多技术 ...
...in the script.
/S runs the installer or uninstaller silently. See section 4.12 for more information.
/D sets the default installation directory ($INSTDIR), overriding InstallDir and InstallDirRegKey. It must be the lastparameter used in the command line and must not contain any quotes, even if the...
wandbox：C++在线编译项目源码编译及原理剖析 - 开源 & Github - 清泛网 - ...
...核心代码在kernel2中，安装步骤也在里面的 README.md 中。
4、编译安装：
cd kennel2
./cmake.sh
cd /home/qpzhou/sources/wandbox/kennel2/_build/release
make install
具体参考项目README.md，持续更新。
虽然功能强大，源码相对还是比较简单的，...
Undefined behavior and sequence points
...s answer is for the older versions of the C++ standard. The C++11 and C++14 versions of the standard do not formally contain 'sequence points'; operations are 'sequenced before' or 'unsequenced' or 'indeterminately sequenced' instead. The net effect is essentially the same, but the terminology is ...
cartesian product in pandas
...port DataFrame, merge
df1 = DataFrame({'key':[1,1], 'col1':[1,2],'col2':[3,4]})
df2 = DataFrame({'key':[1,1], 'col3':[5,6]})
merge(df1, df2,on='key')[['col1', 'col2', 'col3']]
Output:
col1 col2 col3
0 1 3 5
1 1 3 6
2 2 4 5
3 2 4 6
See here f...
How do I specify a password to 'psql' non-interactively?
...
154
From the official documentation:
It is also convenient to have a ~/.pgpass file to avoid reg...