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dplyr summarise: Equivalent of “.drop=FALSE” to keep groups with zero length in output
When using summarise with plyr 's ddply function, empty categories are dropped by default. You can change this behavior by adding .drop = FALSE . However, this doesn't work when using summarise with dplyr . Is there another way to keep empty categories in the result?
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leading zeros in rails
I have fields hr and min , both integers in my application. For hr field, if the user enters "1" I would like Rails to automatically pad it to "01" before saving it to the database. Also for the min field if the user enter "0" it should put in as "00".
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Representing and solving a maze given an image
What is the best way to represent and solve a maze given an image?
10 Answers
10
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How do I get time of a Python program's execution?
I have a command line program in Python that takes a while to finish. I want to know the exact time it takes to finish running.
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How to get the primary IP address of the local machine on Linux and OS X? [closed]
I am looking for a command line solution that would return me the primary (first) IP address of the localhost, other than 127.0.0.1
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Why does Lua have no “continue” statement?
I have been dealing a lot with Lua in the past few months, and I really like most of the features but I'm still missing something among those:
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Paging UICollectionView by cells, not screen
I have UICollectionView with horizontal scrolling and there are always 2 cells side-by-side per the entire screen. I need the scrolling to stop at the begining of a cell. With paging enabled, the collection view scrolls the whole page, which is 2 cells at once, and then it stops.
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How to include “zero” / “0” results in COUNT aggregate?
I've just got myself a little bit stuck with some SQL. I don't think I can phrase the question brilliantly - so let me show you.
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What causes a java.lang.ArrayIndexOutOfBoundsException and how do I prevent it?
What does ArrayIndexOutOfBoundsException mean and how do I get rid of it?
25 Answers
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Prevent body scrolling but allow overlay scrolling
I've been searching for a "lightbox" type solution that allows this but haven't found one yet (please, suggest if you know of any).
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