小编mob*_*upu的帖子

I'm trying to parallelize a script, but for an unknown reason the kernel just freeze without any errors thrown.

minimal working example:

from multiprocessing import Pool

def f(x):
  return x*x

p = Pool(6)
print(p.map(f, range(10)))   

Interestingly, all works fine if I define my function in another file then import it. How can I make it work without the need of another file?

I work with spyder (anaconda) and I have the same result if I run my code from the …

如果条件如下,我必须写重复的其他内容:

  if (d_hand[1]==1){
    state=score(p_hand)-1
  } else if (d_hand[1]==2){
    state=19+score(p_hand)
  } else if (d_hand[1]==3){
    state=39+score(p_hand)
  } else if (d_hand[1]==4){
    state=59+score(p_hand)
  } else if (d_hand[1]==5){
    state=79+score(p_hand)
  } else if (d_hand[1]==6){
    state=99+score(p_hand)
  }

你知道它是否可以更快/更快地写出来吗？我想过做一个if循环,但效率会降低,因为必须检查每个语句.

unpivot当列数相当低并且列的名称可以硬编码时，我已经看到了一些火花数据框的解决方案。您是否有可扩展的解决方案来对包含多列的数据框进行逆透视？

下面是一个玩具问题。

输入：

  val df = Seq(
    (1,1,1,0),
    (2,0,0,1)    
  ).toDF("ID","A","B","C")

+---+--------+----+
| ID|  A | B | C  |
+---+--------+-----
|  1|  1 | 1 | 0  |
|  2|  0 | 0 | 1  |
+---+----------+--+

预期结果：

+---+-----+-----+
| ID|names|count|
+---+-----------|
|  1|  A  |  1  |
|  1|  B  |  1  |
|  1|  C  |  0  |
|  2|  A  |  0  |
|  2|  B  |  0  |
|  2|  C  |  1  |
+---+-----------+ …