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Replacing blank values (white space) with NaN in pandas
I want to find all values in a Pandas dataframe that contain whitespace (any arbitrary amount) and replace those values with NaNs.
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When to use Common Table Expression (CTE)
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I use them to break up complex queries, especially complex joins and sub-queries. I find I'm using them more and more as 'pseudo-views' to help me get my head around the intent of the query.
My only complaint about them is they cannot be re-used. For example, I may have...
Make virtualenv inherit specific packages from your global site-packages
...ch will contain just some libraries (which i chose) of the base python installation.
4 Answers
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echo that outputs to stderr
...criptors will refer to the same file: the one file descriptor #2 was originally referring to. For more information see the Bash Hackers Illustrated Redirection Tutorial.
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How can I concatenate NSAttributedStrings?
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NSMutableAttributedString *mutableAttString = [[NSMutableAttributedString alloc] init];
NSString *plainString = // ...
NSDictionary *attributes = // ... a dictionary with your attributes.
NSAttributedString *newAttString = [[NSAttributedString alloc] initWithString:plainString attributes:attribute...
Determine which MySQL configuration file is being used
...inux, then start the 'mysqld' with strace, for eg strace ./mysqld.
Among all the other system calls, you will find something like:
stat64("/etc/my.cnf", 0xbfa3d7fc) = -1 ENOENT (No such file or directory)
stat64("/etc/mysql/my.cnf", {st_mode=S_IFREG|0644, st_size=4227, ...}) = 0
open("/etc/...
PHP, get file name without file extension
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No need for all that. Check out pathinfo(), it gives you all the components of your path.
Example from the manual:
$path_parts = pathinfo('/www/htdocs/index.html');
echo $path_parts['dirname'], "\n";
echo $path_parts['basename'], "\n"...
How to “undelete” a deleted folder in Subversion / TortoiseSVN?
We have accidentally deleted the 'tags' folder from our Subversion repository where we only intended to delete one specific tag. What is the easiest way to get the 'tags' folder back?
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Object.getOwnPropertyNames vs Object.keys
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There is a little difference. Object.getOwnPropertyNames(a) returns all own properties of the object a. Object.keys(a) returns all enumerable own properties. It means that if you define your object properties without making some of them enumerable: false these two methods will give you the sa...
CSS Background Opacity [duplicate]
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It's not really correct to say that "Children inherit opacity". They don't. It's just that if a child is contained in a parent with opacity, the child will have opacity: 1, but the parent applies it's opacity to itself including all it'...