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Group by multiple columns in dplyr, using string vector input
...
Since this question was posted, dplyr added scoped versions of group_by (documentation here). This lets you use the same functions you would use with select, like so:
data = data.frame(
asihckhdoydkhxiydfgfTgdsx = sample(LETTERS[1:3], 100, replace=TRUE),
a30mvxigxkghc5cdsvxvyv0ja = s...
Getting the max value of an enum
...m MyEnum
{
ValueOne,
ValueTwo
}
VB:
Public Function GetMaxValue _
(Of TEnum As {IComparable, IConvertible, IFormattable})() As TEnum
Dim type = GetType(TEnum)
If Not type.IsSubclassOf(GetType([Enum])) Then _
Throw New InvalidCastException _
("Cannot cast ...
What's the difference between the atomic and nonatomic attributes?
... variables; they will be synthesized automatically, too, and will have an _ prepended to their name to prevent accidental direct access).
With "atomic", the synthesized setter/getter will ensure that a whole value is always returned from the getter or set by the setter, regardless of setter activi...
Convert JavaScript string in dot notation into an object reference
... given somewhere (e.g. developer.mozilla.org/en/JavaScript/Reference/Global_Objects/… ).
– ninjagecko
Jun 18 '11 at 6:12
...
MySQL > Table doesn't exist. But it does (or it should)
...tory directly using command
cp -r /path/to/my/database /var/lib/mysql/new_database
If you do this with a database that uses InnoDB tables, you will get this crazy 'table does not exist' error mentioned above.
The issue is that you need the ib* files in the root of the MySQL datadir (e.g. ibdata...
Is there a way to make GHC provide the type class constraints of typed holes?
...ing, this isn't immediately obvious in GHCi. With your example,
> show _
<interactive>:7:6: error:
• Found hole: _h :: ()
Or perhaps ‘_h’ is mis-spelled, or not in scope
• In the first argument of ‘show’, namely ‘_h’
In the expression: show _h
I...
jsoncpp 不能处理__int64(long long)类型数据 - C/C++ - 清泛网 - 专注C/C++及内核技术
jsoncpp 不能处理__int64(long long)类型数据jsoncpp，是一个c++的解析和生成json的开源工具。如果你的c++程序需要解析或生成json，它会使这个过程变得很简单！但是，今天在用jsoncpp进...jsoncpp，是一个c++的解析和生成json的开源工具。如...
Visual Studio 2013 Update 4【VS2013 SP4 旗舰版下载地址】 - 更多技术 - ...
...(Chinese-Simplified)：7255 MB
发布日期： 2014/11/12
文件名： cn_visual_studio_ultimate_2013_with_update_4_x86_dvd_5935081.iso
语言： Chinese - Simplified
SHA1：5F924E3B8F6715F92DCD2F8E58558833D310A146
http://download.microsoft.com/do ... s2013.4_ult_chs.iso
Visual Studio Ultima...
Visual Studio 2013 Update 4【VS2013 SP4 旗舰版下载地址】 - 其他 - 清泛...
...(Chinese-Simplified)：7255 MB
发布日期： 2014/11/12
文件名： cn_visual_studio_ultimate_2013_with_update_4_x86_dvd_5935081.iso
语言： Chinese - Simplified
SHA1：5F924E3B8F6715F92DCD2F8E58558833D310A146
http://download.microsoft.com/do ... s2013.4_ult_chs.iso
Visual Studio Ultima...
Fastest method to replace all instances of a character in a string [duplicate]
...
You can use the following:
newStr = str.replace(/[^a-z0-9]/gi, '_');
or
newStr = str.replace(/[^a-zA-Z0-9]/g, '_');
This is going to replace all the character that are not letter or numbers to ('_'). Simple change the underscore value for whatever you want to replace it.
...