大约有 44,900 项符合查询结果（耗时：0.0277秒） [XML]
How to open multiple pull requests on GitHub
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edited Oct 27 '19 at 13:17
ahmednabil88
11.8k99 gold badges3939 silver badges7878 bronze badges
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Pass a data.frame column name to a function
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You can just use the column name directly:
df <- data.frame(A=1:10, B=2:11, C=3:12)
fun1 <- function(x, column){
max(x[,column])
}
fun1(df, "B")
fun1(df, c("B","A"))
There's no need to use substitute, eval, etc.
You can even pass the desired function as a parameter:
fun1 <- function...
What is the purpose and use of **kwargs?
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edited Jul 29 '18 at 23:24
omkaartg
2,03811 gold badge66 silver badges2121 bronze badges
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Difference between array_map, array_walk and array_filter
... preserve the keys.
Example:
<pre>
<?php
$origarray1 = array(2.4, 2.6, 3.5);
$origarray2 = array(2.4, 2.6, 3.5);
print_r(array_map('floor', $origarray1)); // $origarray1 stays the same
// changes $origarray2
array_walk($origarray2, function (&$v, $k) { $v = floor($v); });
print_...
Overloading Macro on Number of Arguments
I have two macros FOO2 and FOO3 :
8 Answers
8
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Android Studio: how to attach Android SDK sources?
...able only for API levels 14 and above.
UPDATE ( Based on stable release 3.2.1):
Google changes the approach of shipping the sources, so lets see what changed.
Go to the following location
Preferences -> Apperance & Behaviour -> System Settings -> Android SDK
Quite lazy to navigate...
R: += (plus equals) and ++ (plus plus) equivalent from c++/c#/java, etc.?
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edited Jan 26 '18 at 13:02
zx8754
38.6k1010 gold badges8787 silver badges146146 bronze badges
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SSH to Elastic Beanstalk instance
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I found it to be a 2-step process. This assumes that you've already set up a keypair to access EC2 instances in the relevant region.
Configure Security Group
In the AWS console, open the EC2 tab.
Select the relevant region and click on Secur...
Outputting data from unit test in python
...hat, like me, comes here looking for a simple and quick answer.
In Python 2.7 you could use an additional parameter msg to add information to the error message like this:
self.assertEqual(f.bar(t2), 2, msg='{0}, {1}'.format(t1, t2))
Offical docs here
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Performance of foreach, array_map with lambda and array_map with static function
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122
FWIW, I just did the benchmark since poster didn't do it. Running on PHP 5.3.10 + XDebug.
UPD...