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Pandas: create two new columns in a dataframe with values calculated from a pre-existing column
...he top answer is flawed in my opinion. Hopefully, no one is mass importing all of pandas into their namespace with from pandas import *. Also, the map method should be reserved for those times when passing it a dictionary or Series. It can take a function but this is what apply is used for.
So, if ...
How can I obtain the element-wise logical NOT of a pandas Series?
...
Wierd, I actually tested the tilde as it was mentioned in the documentation, but it didn't perform the same as np.invert :S
– root
Apr 14 '13 at 13:11
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'typeid' versus 'typeof' in C++
...perator which returns type identification information at run time. It basically returns a type_info object, which is equality-comparable with other type_info objects.
Note, that the only defined property of the returned type_info object has is its being equality- and non-equality-comparable, i.e. t...
What's wrong with cplusplus.com?
...of iterators only and does not know anything about the container which actually contains the items. In fact, it's not possible for std::remove to know the underlying container, because there is no way it can go from a pair of iterators to discover about the container to which the iterators belong. S...
If vs. Switch Speed
Switch statements are typically faster than equivalent if-else-if statements (as e.g. descibed in this article ) due to compiler optimizations.
...
How to expire session due to inactivity in Django?
...just have to make some urls and views to return relevant data to the ajax calls regarding the session expiry.
when the user opts to "renew" the session, so to speak, all you have to do is set requeset.session['last_activity'] to the current time again
Obviously this code is only a start... but it ...
Using multiple let-as within a if-statement in Swift
...e code inside the if-let block won't be executed.
Note: the clauses don't all have to be 'let' clauses, you can have any series of boolean checks separated by commas.
For example:
if let latitudeDouble = latitude as? Double, importantThing == true {
// latitudeDouble is non-optional in here ...
Sprintf equivalent in Java
...atting with an instance method makes little sense, as it would have to be called like:
String formatted = "%s: %s".format(key, value);
The original Java authors (and .NET authors) decided that a static method made more sense in this situation, as you are not modifying the target, but instead call...
Is it possible to roll back CREATE TABLE and ALTER TABLE statements in major SQL databases?
...cle Database 11g Release 2 and above - by default, no, but an alternative called edition-based redefinition exists
Older versions of Oracle - no; DDL causes an implicit commit
SQL Server - yes
Sybase Adaptive Server - yes
DB2 - yes
Informix - yes
Firebird (Interbase) - yes
SQLite also appears to h...
How do you use NSAttributedString?
... string:
NSMutableAttributedString * string = [[NSMutableAttributedString alloc] initWithString:@"firstsecondthird"];
[string addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(0,5)];
[string addAttribute:NSForegroundColorAttributeName value:[UIColor greenColor] ...