大约有 47,000 项符合查询结果（耗时：0.0822秒） [XML]
Pass a data.frame column name to a function
...
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...
Overloading Macro on Number of Arguments
I have two macros FOO2 and FOO3 :
8 Answers
8
...
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_...
undefined method `source_index' for Gem:Module (NoMethodError)
I'm running a Rails 2.3.5 application and upon running script/server I am shown the following:
5 Answers
...
Matplotlib 2 Subplots, 1 Colorbar
...
329
Just place the colorbar in its own axis and use subplots_adjust to make room for it.
As a quic...
SSH to Elastic Beanstalk instance
...
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...
What is the difference between ~> and >= when specifying rubygem in Gemfile?
...
2 Answers
2
Active
...
Simple way to find if two different lists contain exactly the same elements?
...f you care about order, then just use the equals method:
list1.equals(list2)
From the javadoc:
Compares the specified object with
this list for equality. Returns true
if and only if the specified object is
also a list, both lists have the same
size, and all corresponding pairs of
el...
Multiple levels of 'collection.defaultdict' in Python
...
|
edited Sep 12 '19 at 19:45
StevenWernerCS
45855 silver badges1111 bronze badges
answered A...
What's the difference between ASCII and Unicode?
...
ASCII defines 128 characters, which map to the numbers 0–127. Unicode defines (less than) 221 characters, which, similarly, map to numbers 0–221 (though not all numbers are currently assigned, and some are reserved).
Unicode is a super...