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Summarizing multiple columns with dplyr? [duplicate]
... a bit with the dplyr-syntax. I have a data frame with different variables and one grouping variable. Now I want to calculate the mean for each column within each group, using dplyr in R.
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What is time_t ultimately a typedef to?
I searched my Linux box and saw this typedef:
10 Answers
10
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What are the rules for JavaScript's automatic semicolon insertion (ASI)?
...ing token is }.
When the end of the input stream of tokens is encountered and the parser is unable to parse the input token stream as a single complete Program, then a semicolon is automatically inserted at the end of the input stream.
e.g.:
a = b
++c
is transformed to:
a = b;
++c...
Why would you ever implement finalize()?
...ve been reading through a lot of the rookie Java questions on finalize() and find it kind of bewildering that no one has really made it plain that finalize() is an unreliable way to clean up resources. I saw someone comment that they use it to clean up Connections, which is really scary since the...
Visual Studio 2013 and BitBucket
...nter the URL to your BitBucket repository (must already exist in BitBucket and must be empty) and click "Publish"
Enter your BitBucket credentials when prompted. After the publish finishes you'll get a results message like this.
Use the "Sync" button to update BitBucket with your local co...
Does Java support default parameter values?
...
No, the structure you found is how Java handles it (that is, with overloading instead of default parameters).
For constructors, See Effective Java: Programming Language Guide's Item 1 tip (Consider static factory methods instead of constructors) if the overloading ...
Python (and Python C API): __new__ versus __init__
...stion I'm about to ask seems to be a duplicate of Python's use of __new__ and __init__? , but regardless, it's still unclear to me exactly what the practical difference between __new__ and __init__ is.
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How to use the new affix plugin in twitter's bootstrap 2.1.0?
...ocs with the affix navbar: The navbar is below a paragraph / page heading, and upon scrolling down it should first scroll along until reaching the top of the page, and then stick there fixed for further scrolldowns.
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Can you have if-then-else logic in SQL? [duplicate]
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The CASE statement is the closest to an IF statement in SQL, and is supported on all versions of SQL Server:
SELECT CASE <variable>
WHEN <value> THEN <returnvalue>
WHEN <othervalue> THEN <returnthis>
ELSE <retur...
How do I list the functions defined in my shell?
...
declare -F
Function names and definitions may be listed with the -f option to the
declare builtin command (see Bash Builtins). The -F option to declare
will list the function names only
(and optionally the source file and line number).
Bash Re...