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Repeat each row of data.frame the number of times specified in a column
What is the simplest way to expand each row the first two columns of the data.frame above, so that each row is repeated the number of times specified in the column 'freq'?
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How to concatenate two MP4 files using FFmpeg?
I'm trying to concatenate two mp4 files using ffmpeg. I need this to be an automatic process hence why I chose ffmpeg. I'm converting the two files into .ts files and then concatenating them and then trying to encode that concated .ts file. The files are h264 and aac encoded and I'm hoping to kee...
Postfix日常维护队列管理 - 更多技术 - 清泛网 - 专注C/C++及内核技术
Postfix日常维护队列管理postfix有四种不同的邮件队列，并且由队列管理进程统一进行管理： 1． maildrop：本地邮件放置在maildrop中，同时也被拷贝到incoming中...postfix有四种不同的邮件队列，并且由队列管理进程统一进行管理：
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Win7以上操作系统清理系统图标缓存脚本 - 更多技术 - 清泛网 - 专注C/C++及内核技术
...理系统图标缓存脚本rem 关闭Windows外壳程序explorertaskkill f im explorer.exerem 清理系统图标缓存数据库attrib -h -s -r "%userprofile% AppDa...
rem 关闭Windows外壳程序explorer
taskkill /f /im explorer.exe
rem 清理系统图标缓存数据库
attrib -h -s -r "%use...
快速开发CSS的利器LESS 系列教程 - 更多技术 - 清泛网 - 专注C/C++及内核技术
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基本demo：
<!doctype html>
<html>
<head>
<meta charset="UTF-8">
<title>快速开发CSS的利器 - 初识less</title>
<link type="text/less" rel="stylesheet/less" href="test.less" />
<script src="less.js"></script>
</head>
<body>
<div class="con">
独行...
Rearrange columns using cut
I am having a file in the following format
8 Answers
8
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Printing the last column of a line in a file
I have a file that is constantly being written to/updated. I want to find the last line containing a particular word, then print the last column of that line.
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Split (explode) pandas dataframe string entry to separate rows
I have a pandas dataframe in which one column of text strings contains comma-separated values. I want to split each CSV field and create a new row per entry (assume that CSV are clean and need only be split on ','). For example, a should become b :
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Rails select helper - Default selected value, how?
Here is a piece of code I'm using now:
15 Answers
15
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Implications of foldr vs. foldl (or foldl')
Firstly, Real World Haskell , which I am reading, says to never use foldl and instead use foldl' . So I trust it.
7 A...