大约有 44,000 项符合查询结果（耗时：0.0500秒） [XML]
Relative frequencies / proportions with dplyr
...se(n = n()) %>%
mutate(freq = n / sum(n))
# am gear n freq
# 1 0 3 15 0.7894737
# 2 0 4 4 0.2105263
# 3 1 4 8 0.6153846
# 4 1 5 5 0.3846154
From the dplyr vignette:
When you group by multiple variables, each summary peels off one level of the grouping. That mak...
jQuery attr vs prop?
...
71
Unfortunately none of your links work :(
Some insight though, attr is for all attributes. prop i...
How to perform element-wise multiplication of two lists?
...
14 Answers
14
Active
...
Minimum and maximum date
...
179
From the spec, §15.9.1.1:
A Date object contains a Number indicating a particular instant in...
leading zeros in rails
...min , both integers in my application. For hr field, if the user enters "1" I would like Rails to automatically pad it to "01" before saving it to the database. Also for the min field if the user enter "0" it should put in as "00".
...
What is the best way to auto-generate INSERT statements for a SQL Server table?
...
1055
Microsoft should advertise this functionality of SSMS 2008. The feature you are looking for i...
Cleaning `Inf` values from an R dataframe
...
121
Option 1
Use the fact that a data.frame is a list of columns, then use do.call to recreate a ...
Find integer index of rows with NaN in pandas dataframe
...
11 Answers
11
Active
...
C++ 读写xml方法整理（持续更新） - C/C++ - 清泛网 - 专注C/C++及内核技术
...八门，太多了，这里对常用的几种做一个总结，附demo。1、Markup 下载：
特点：C++编写的，一个.h，一个.cpp，绿色小巧，直接加入工程源码编译，只支持MFC。
<?xml version="1.0" encoding="utf-8"?>
<root>
<update ver="1.2.0" pkg="setup.exe" force...