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Changing column names of a data frame
...e called). The lesson here is, "don't write your code in an 'editor' that converts quotes to smart-quotes".
names(newprice)[1]<-paste(“premium”) # error
names(newprice)[1]<-paste("premium") # works
Also, you don't need paste("premium") (the call to paste is redundant) and it's a good...
How to find index of list item in Swift?
...
As swift is in some regards more functional than object-oriented (and Arrays are structs, not objects), use the function "find" to operate on the array, which returns an optional value, so be prepared to handle a nil value:
let arr:Array = ["a","b","c"]
find(arr, "c")! // 2
fi...
What are .dex files in Android?
... files. But after .class files are generated, the “dx” tool is used to convert all .class files into a single .dex, or Dalvik Executable, file. It is the .dex file that is executed on the Dalvik VM. The .dex file has been optimized for memory usage and the design is primarily driven by sharing o...
javascript check for not null
...lsey". The double-not operator !! will remove more than just null. It will convert NaN and undefined into false as well. And that's why your array filters correctly when using the double not-operator !!.
– tfmontague
Aug 6 '16 at 20:50
...
ATL正则表达式库使用 - C/C++ - 清泛网 - 专注C/C++及内核技术
...典型使用方法：
#include "stdafx.h"
#include <atlrx.h>
int main(int argc, char* argv[])
{
CAtlRegExp<> reUrl;
// five match groups: scheme, authority, path, query, fragment
REParseError status = reUrl.Parse(
"({[^:/?#]+}:)?(//{[^/?#]*})?{[^?#]*}(?{[^#]*})?(...
Are nullable types reference types?
...Guide):
Nullable types are instances of the System.Nullable struct.
and
Nullable types represent value-type variables that can be assigned the value of null. You cannot create a nullable type based on a reference type. (Reference types already support the null value.)
So, no they're not...
Search all tables, all columns for a specific value SQL Server [duplicate]
...n by: Narayana Vyas Kondreddi
-- Site: http://vyaskn.tripod.com
-- Updated and tested by Tim Gaunt
-- http://www.thesitedoctor.co.uk
-- http://blogs.thesitedoctor.co.uk/tim/2010/02/19/Search+Every+Table+And+Field+In+A+SQL+Server+Database+Updated.aspx
-- Tested on: SQL Server 7.0, SQL Server 2000, SQ...
How can I define a composite primary key in SQL?
...rID)
);
The pair (QuestionID,MemberID) must then be unique for the table and neither value can be NULL. If you do a query like this:
SELECT * FROM voting WHERE QuestionID = 7
it will use the primary key's index. If however you do this:
SELECT * FROM voting WHERE MemberID = 7
it won't because...
UTF-8 without BOM
...pt files that I need them to be saved in UTF-8 (without BOM), every time I convert them to the correct format in Notepad++ , they are reverted back to UTF-8 with BOM when I open them in Visual Studio. How can I stop VS2010 from doing that?
...
ImportError: No module named site on Windows
...h this problem, see my comment on the main question. Basically you need to convert PYTHONPATH to a windows-style path with export PYTHONPATH=$(cygpath -w $PYTHONPATH).
– robert
Aug 19 '14 at 13:13
...