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Extract a dplyr tbl column as a vector
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This seems the most versatile method as it works identically with vectors and data.frames, i.e. it enables functions to be more agnostic.
– geotheory
Mar 14 '17 at 10:03
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Ruby - test for array
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Type checking is for Java. Go ahead and just call count on the variable. Write unit tests to make sure the method works as expected.
– user132447
Mar 21 '12 at 14:55
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How can one print a size_t variable portably using the printf family?
...on is to cast your variables to unsigned long long and use %llu to be maximally portable.
– Adam Rosenfield
Apr 13 '10 at 1:52
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show 12 mor...
How do I scroll the UIScrollView when the keyboard appears?
... handling of this issue is explained. You should have a look into it.
// Call this method somewhere in your view controller setup code.
- (void)registerForKeyboardNotifications
{
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(keyboardWasShown:)
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Unresolved external symbol on static class members
...als here:
For me, the thing that I forgot was to mark my class definition __declspec(dllexport), and when called from another class (outside that class's dll's boundaries), I of course got the my unresolved external error.
Still, easy to forget when you're changing an internal helper class to a one...
Remove rows with all or some NAs (missing values) in data.frame
...G00000221312 0 1 2 3 2
na.omit is nicer for just removing all NA's. complete.cases allows partial selection by including only certain columns of the dataframe:
> final[complete.cases(final[ , 5:6]),]
gene hsap mmul mmus rnor cfam
2 ENSG00000199674 0 2 2 ...
Having Django serve downloadable files
..._str(file_name)
response['X-Sendfile'] = smart_str(path_to_file)
# It's usually a good idea to set the 'Content-Length' header too.
# You can also set any other required headers: Cache-Control, etc.
return response
Of course, this will only work if you have control over your server, or your hostin...
Only read selected columns
...g","Sep","Oct","Nov","Dec"))
dat <- fread("data.txt", drop = c(8:13))
All result in:
> data
Year Jan Feb Mar Apr May Jun
1 2009 -41 -27 -25 -31 -31 -39
2 2010 -41 -27 -25 -31 -31 -39
3 2011 -21 -27 -2 -6 -10 -32
UPDATE: When you don't want fread to return a data.table, use the data.ta...
Pandas aggregate count distinct
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How about either of:
>>> df
date duration user_id
0 2013-04-01 30 0001
1 2013-04-01 15 0001
2 2013-04-01 20 0002
3 2013-04-02 15 0002
4 2013-04-02 30 0002
>>> df.groupby("date").agg({"duration": np.sum, "use...
What is the purpose of using -pedantic in GCC/G++ compiler?
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GCC compilers always try to compile your program if this is at all possible. However, in some
cases, the C and C++ standards specify that certain extensions are forbidden. Conforming compilers
such as gcc or g++ must issue a diagnostic when these extensions are encountered. For example,
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