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Pandas count(distinct) equivalent
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What if I have multiple columns that I want to be unique together, like in .drop_duplicates(subset=['col1','col2'])?
– ErnestScribbler
Oct 2 '17 at 8:10
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Matrix Transpose in Python
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if you're going to iterate through the results, izip from itertools can save memory for large arrays.
– Antony Hatchkins
Mar 28 '13 at 8:38
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A variable modified inside a while loop is not remembered
...or the original Bourne shell, but don't have access to a running copy just now to check.
There is, however, a very trivial workaround to the problem.
Change the first line of the script from:
#!/bin/bash
to
#!/bin/ksh
Et voila! A read at the end of a pipeline works just fine, assuming you ha...
dynamic_cast and static_cast in C++
...t runtime, and work by querying the object (no need to worry about how for now), asking it if it the type we're looking for. If it is, dynamic_cast<Type*> returns a pointer; otherwise it returns NULL.
In order for this base-to-derived casting to work using dynamic_cast<>, Base, Foo and...
How can I change a file's encoding with vim?
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all our base encoding are now belong to UTF-8
– roblogic
Aug 25 '15 at 1:49
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How can I clear event subscriptions in C#?
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If you're stubborn, you can force it clear via reflection. See stackoverflow.com/questions/91778/… .
– Brian
Oct 29 '10 at 21:36
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Pimpl idiom vs Pure virtual class interface
...s case, because it's the only member) from the pointer to the A object it knows to be this.
On the user side of the code, a new A will first allocate sizeof(A) bytes of memory, then hand a pointer to that memory to the A::A() constructor as this.
If in a later revision of your library you decide t...
Adding minutes to date time in PHP
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With date: 2011-11-18 00:00 if I add 5 mins, I get 2012-04-18 00:00 as a result. ` $time = new DateTime($_REQUEST['start']); $time->add(new DateInterval('P' . $duration . 'M')); $endTime = $time->format('Y-m-d H:i'); echo $endTime; ` Applogies f...
Mysql: Select rows from a table that are not in another
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If you have 300 columns as you mentioned in another comment, and you want to compare on all columns (assuming the columns are all the same name), you can use a NATURAL LEFT JOIN to implicitly join on all matching column names...
What does the filter parameter to createScaledBitmap do?
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Also, do you know if it's doing area averaging if you pass filter = true?
– clahey
Nov 5 '10 at 15:36
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