大约有 40,100 项符合查询结果（耗时：0.0253秒） [XML]
What is the ultimate postal code and zip regex?
...le IMO. But you would still be missing on the validation part: Zip code 12345 may exist, but 12346 not, maybe 12344 doesn't exist either. How do you check for that with a regex?
You can't.
share
|
...
Can dplyr package be used for conditional mutating?
...f %>%
mutate(g = ifelse(a == 2 | a == 5 | a == 7 | (a == 1 & b == 4), 2,
ifelse(a == 0 | a == 1 | a == 4 | a == 3 | c == 4, 3, NA)))
Added - if_else: Note that in dplyr 0.5 there is an if_else function defined so an alternative would be to replace ifelse with if_else; howev...
Why does “,,,” == Array(4) in Javascript?
...d operand is converted to a string and the string representation of Array(4) is ,,,:
> Array(4).toString()
",,,"
If you use the array constructor function and pass a number, it sets the length of the array to that number. So you can say you have four empty indexes (same as [,,,]) and the de...
How to select .NET 4.5.2 as a target framework in Visual Studio
I have installed .NET Framework 4.5.2 on Windows 8.1. But in Visual Studio 2013 I do not see the .NET Framework 4.5.2 option (see screenshot). How do I target my project for .NET 4.5.2?
...
Split a vector into chunks in R
...(), split() and ceiling():
> d <- rpois(73,5)
> d
[1] 3 1 11 4 1 2 3 2 4 10 10 2 7 4 6 6 2 1 1 2 3 8 3 10 7 4
[27] 3 4 4 1 1 7 2 4 6 0 5 7 4 6 8 4 7 12 4 6 8 4 2 7 6 5
[53] 4 5 4 5 5 8 7 7 7 6 2 4 3 3 8 11 6 6 1 8 4
> m...
Assign multiple columns using := in data.table, by group
...b col1 col2
# 1: 1 1 hi hello
# 2: 2 2 hi hello
# 3: 3 3 hi hello
# 4: 1 4 hi hello
# 5: 2 5 hi hello
# 6: 3 6 hi hello
x[ , c("mean", "sum") := list(mean(b), sum(b)), by = a][]
# a b col1 col2 mean sum
# 1: 1 1 hi hello 2.5 5
# 2: 2 2 hi hello 3.5 7
# 3: 3 3 hi hello ...
What Are the Differences Between PSR-0 and PSR-4?
... I can't seem to grasp what the actual difference is between PSR-0 and PSR-4.
5 Answers
...
What is the difference between Gemfile and Gemfile.lock in Ruby on Rails
... |
edited Mar 29 '18 at 14:02
cori
7,98377 gold badges3939 silver badges7676 bronze badges
answered Aug...
CGRidCtrl控件 学习心得 - C/C++ - 清泛网 - 专注C/C++及内核技术
...能介绍... 1
2.2 框架介绍... 2
2.3 主要类介绍... 4
2.3.1 CGridCtrl类... 4
2.3.2 CGridCellCheck类... 5
2.3.3 CGridCellCombo类... 7
2.4 控件类CGridCtrl常用函数说明... 10
2.4.1 行和列的设置... 10
2.4.2 单元格信息设置.....
cpuid汇编指令 - C/C++ - 清泛网 - 专注C/C++及内核技术
...令cpuid就是一条读取CPU各种信息的一条指令，大概是从80486的某个版本开始就存在了。 CPUID这条指令，除了用于识别CPU（CPU的型号...cpuid指令
cpuid就是一条读取CPU各种信息的一条指令，大概是从80486的某个版本开始就存在了。 CP...