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pandas read_csv and filter columns with usecols
...nts.
names is only necessary when there is no header and you want to specify other arguments using column names rather than integer indices.
usecols is supposed to provide a filter before reading the whole DataFrame into memory; if used properly, there should never be a need to delete columns afte...
How can I use an http proxy with node.js http.Client?
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if you get bad request, put path: '/'
– Laurent Debricon
Jun 1 '13 at 12:03
9
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Add default value of datetime field in SQL Server to a timestamp
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For modifying an existing column in an existing table:
ALTER TABLE YourTable ADD CONSTRAINT DF_YourTable DEFAULT GETDATE() FOR YourColumn
share
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Regex: Specify “space or start of string” and “space or end of string”
...#the | means or. () is a capturing group.
/\b(stackoverflow)\b/
Also, if you don't want to include the space in your match, you can use lookbehind/aheads.
(?<=\s|^) #to look behind the match
(stackoverflow) #the string you want. () optional
(?=\s|$) #to look ahead.
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Does the join order matter in SQL?
...ON (a.x, a.y) = (b.x, b.y) and the two queries would still be equivalent.
If however, any of these involved IS NULL or a function that is related to nulls like COALESCE(), for example if the condition was b.ab_id IS NULL, then the two queries would not be equivalent.
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How to $http Synchronous call with AngularJS
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Not currently. If you look at the source code (from this point in time Oct 2012), you'll see that the call to XHR open is actually hard-coded to be asynchronous (the third parameter is true):
xhr.open(method, url, true);
You'd need to w...
When increasing the size of VARCHAR column on a large table could there be any problems?
...rom (200 to 1200) on a table with about 500k rows. What I need to know is if there are any issues I have not considered.
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Converting NSString to NSDate (and back again)
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Swift 4 and later
Updated: 2018
String to Date
var dateString = "02-03-2017"
var dateFormatter = DateFormatter()
// This is important - we set our input date format to match our input string
// if the format doesn't match y...
Why can lambdas be better optimized by the compiler than plain functions?
...so passing them to a function template will instantiate a new function specifically for that object. The compiler can thus trivially inline the lambda call.
For functions, on the other hand, the old caveat applies: a function pointer gets passed to the function template, and compilers traditionally...
CodeIgniter removing index.php from url
...— this file
index.php
Step:-3 Write below code in .htaccess file
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L]
</IfModule>
Step:-4 In some case the default setting for uri_prot...