嵌入一​​个函数另一个Jython

Question

赋值的目标是让两个函数一起工作，或者将setPixeltoBlack调用到setPicturetoblack。

错误很明显：

The error was:'javainstance' object has no attribute '__call__'
Attribute not found.
You are trying to access a part of the object that doesn't exist.
Please check line 10 of /Users/tobiasdouglas/test3

主要问题：如何让计算机检查是否存在两个变量（xpos，ypos）？ 我写了pseduocode（用＃表示）所需的内容。

感谢。

import random
file=pickAFile()
picture=makePicture(file)
show(picture)
xpos = input("Enternumber")
ypos = input("Enternumber")

def setPixelToBlack(getPixel):
#if xpos and ypos = known
  setColor=(getPixel(picture,xpos,ypos),black)
#else
  #setcolor=(getPixels(picture), black)
  explore(picture)
  return

def setPictureToBlack(picture):
  for p in getPixels(picture):
    setPixelToBlack(p)

Answer 1

您可以使用特定值None并使用None或is None检查变量是is not None。

xpos = None
ypos = None

// some code that may set xpos or ypos

def setPixelToBlack(getPixel):
    if xpos is not None and ypos is not None:
        setColor=(getPixel(picture,xpos,ypos),black)
    // ...

同样在您的代码中xpos和ypos是全局变量。您可以在函数中读取它们，但要更改其值，您需要使用global xpos, ypos语句。