大约有 41,475 项符合查询结果（耗时：0.0233秒） [XML]
How do I add the contents of an iterable to a set?
...
231
You can add elements of a list to a set like this:
>>> foo = set(range(0, 4))
>>...
How to convert a scala.List to a java.util.List?
...ort scala.collection.jcl.ArrayList
unconvertList(new ArrayList ++ List(1,2,3))
From Scala 2.8 onwards:
import scala.collection.JavaConversions._
import scala.collection.mutable.ListBuffer
asList(ListBuffer(List(1,2,3): _*))
val x: java.util.List[Int] = ListBuffer(List(1,2,3): _*)
However, asLis...
Xcode/Simulator: How to run older iOS version?
...ut what I'm wondering is if I'll still be able to run the simulator as iOS 3.2. This is because I'm creating iAds for iPad but I still want to check if my program will run with iOS 3.2.
...
How can I force division to be floating point? Division keeps rounding down to 0?
...
In Python 2, division of two ints produces an int. In Python 3, it produces a float. We can get the new behaviour by importing from __future__.
>>> from __future__ import division
>>> a = 4
>>> b = 6
>>> c = a / b
>>> c
0.66666666666666663
...
Pass a data.frame column name to a function
... 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(x, colu...
Repeat each row of data.frame the number of times specified in a column
...), 1:2]
Result:
var1 var2
1 a d
2 b e
2.1 b e
3 c f
3.1 c f
3.2 c f
share
|
improve this answer
|
follow
|
...
Is generator.next() visible in Python 3?
...
3 Answers
3
Active
...
Python “extend” for a dictionary
...
phoenix
3,20611 gold badge2727 silver badges3131 bronze badges
answered Feb 23 '09 at 11:01
Nick FortescueNic...
Pandas groupby: How to get a union of strings
...
In [5]: df
Out[5]:
A B C
0 1 0.749065 This
1 2 0.301084 is
2 3 0.463468 a
3 4 0.643961 random
4 1 0.866521 string
5 2 0.120737 !
In [6]: df.dtypes
Out[6]:
A int64
B float64
C object
dtype: object
When you apply your own function, t...