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Split comma-separated strings in a column into separate rows
...odified according to Rich Scriven's comment,
Jaap's two data.table methods and two dplyr / tidyr approaches,
Ananda's splitstackshapesolution,
and two additional variants of Jaap's data.table methods.
Overall 8 different methods were benchmarked on 6 different sizes of data frames using the micro...
How does @synchronized lock/unlock in Objective-C?
Does @synchronized not use "lock" and "unlock" to achieve mutual exclusion? How does it do lock/unlock then?
5 Answers
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Calculate date from week number
...date of the first day in the week (monday here in Europe). I know the year and the week number? I'm going to do this in C#.
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What's the difference between “squash” and “fixup” in Git/Git Extension?
...the commit log message begins with "squash! ..." (or "fixup!
..."), and there is a commit whose title begins with the same ...,
automatically modify the todo list of rebase -i so that the commit
marked for squashing comes right after the commit to be modified,
and change ...
Pick a random element from an array
Suppose I have an array and I want to pick one element at random.
16 Answers
16
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Turning a Comma Separated string into individual rows
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@NickW this may be because the parts before and after UNION ALL return different types from the LEFT function. Personally I don't see why you wouldn't jump to MAX once you get to 4000...
– RichardTheKiwi
Feb 22 '12 at 8:35
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In Python, how can you load YAML mappings as OrderedDicts?
I'd like to get PyYAML 's loader to load mappings (and ordered mappings) into the Python 2.7+ OrderedDict type, instead of the vanilla dict and the list of pairs it currently uses.
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Difference between setTimeout with and without quotes and parentheses
I am learning JavaScript and I have learned recently about JavaScript timing events. When I learned about setTimeout at W3Schools , I noticed a strange figure which I didn’t run into before. They are using double quotes and then call the function.
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What is the difference between ng-if and ng-show/ng-hide
I'm trying to understand the difference between ng-if and ng-show / ng-hide , but they look the same to me.
12 Answers
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How to create and handle composite primary key in JPA
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You can make an Embedded class, which contains your two keys, and then have a reference to that class as EmbeddedId in your Entity.
You would need the @EmbeddedId and @Embeddable annotations.
@Entity
public class YourEntity {
@EmbeddedId
private MyKey myKey;
@Column(name ...