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Filter data.frame rows by a logical condition
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To select rows according to one 'cell_type' (e.g. 'hesc'), use ==:
expr[expr$cell_type == "hesc", ]
To select rows according to two or more different 'cell_type', (e.g. either 'hesc' or 'bj fibroblast'), use %in%:
expr[expr$cell_type %in% c("...
jQuery $(document).ready and UpdatePanels?
I'm using jQuery to wire up some mouseover effects on elements that are inside an UpdatePanel. The events are bound in $(document).ready . For example:
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Ruby: Can I write multi-line string with no concatenation?
...re are pieces to this answer that helped me get what I needed (easy multi-line concatenation WITHOUT extra whitespace), but since none of the actual answers had it, I'm compiling them here:
str = 'this is a multi-line string'\
' using implicit concatenation'\
' to prevent spare \n\'s'
=> "t...
Finding all possible combinations of numbers to reach a given sum
How would you go about testing all possible combinations of additions from a given set N of numbers so they add up to a given final number?
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How can I plot separate Pandas DataFrames as subplots?
I have a few Pandas DataFrames sharing the same value scale, but having different columns and indices. When invoking df.plot() , I get separate plot images. what I really want is to have them all in the same plot as subplots, but I'm unfortunately failing to come up with a solution to how and would...
Under what conditions is a JSESSIONID created?
..., use request.getSession(false) -- this will return you a session or null. In this case, new session is not created, and JSESSIONID cookie is not sent. (This also means that session isn't necessarily created on first request... you and your code are in control when the session is created)
Sessions ...
What is the best way to implement a “timer”? [duplicate]
...ent a timer? A code sample would be great! For this question, "best" is defined as most reliable (least number of misfires) and precise. If I specify an interval of 15 seconds, I want the target method invoked every 15 seconds, not every 10 - 20 seconds. On the other hand, I don't need nanosecond ac...
How to make Git “forget” about a file that was tracked but is now in .gitignore?
There is a file that was being tracked by git , but now the file is on the .gitignore list.
27 Answers
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What does the exclamation mark do before the function?
...ere's no semicolon: this is just a function declaration. You would need an invocation, foo(), to actually run the function.
Now, when we add the seemingly innocuous exclamation mark: !function foo() {} it turns it into an expression. It is now a function expression.
The ! alone doesn't invoke the ...
Android Game Keeps Getting Hacked [closed]
...or. We setup Google Alerts for all our apps, so we get told daily who's doing the hacking. So far, we have implemented the licensing service as Google has suggested, our salt is randomly made each time the license is initiated with the unique device ID. We run the check service once, when the app...