在 Python 中使用另一个函数中的局部变量？

Question

I have created a text file in one function. For a school project, I have to take that text file, and use the same data to put into another text file, "distance" and then append the variable "equation" to the end of each row in the previous text file. However, I'm stuck on how I can take the x,y,z variables in the first function, and use them in the second function without using a global variable? Help!

def readast():

    astlist=[]
    outFileA=open('asteroids.txt','w')
    letter=65
    size_of_array=15
    astlist=[]*size_of_array
    for i in range(0,size_of_array):
        x=random.randint(1,1000)
        y=random.randint(1,1000)
        z=random.randint(1,1000)

    outFileA.write ('\n'+chr(letter) + '\t' +(str(x)) + '\t' + (str(y)) +'\t' +(str(z)))
    letter= letter+ 1
    return x,y,z
    outFileA.close()

def distance():

    outFileA=open('asteroids.txt','r')
    outFileD=open('distance.txt','w')
    x= (x**2)
    y= (y**2) #these three variables I need to pull from readast
    z= (z**2)
    equation=math.sqrt(x+y+z)

    for row in range(len(outfileA)):
        x,y,z=outFileA[row]
        outFileD.append(equation)
    outFileD.close()

Answer 1

If you can modify the function signatures, parameterize distance :

def distance(x, y, z):

then when you call readast from main , grab the return values:

x, y, z = readast()

and pass x , y , and z as arguments when you call distance from main :

distance(x, y, z)

Note that there are several local variables named x . You are not sharing a local variable between several functions; only its value. Function calls copy the values of arguments into parameters, and then evaluate to their returned value(s).

Answer 2

You're returning (x,y,z) in the first function, which is called by the main function? Make sure that your main function assigns the tuple to something, then pass it as parameters into the second function...

Simplified:

def distance(x,y,z):

   ....



def main():

   ...
   (x ,y ,z) = readast()
   ...

   distance(x,y,z)

Answer 3

The simplest way I think it's through function parameters

def distance(_x, _y, _z):
  outFileA=open('asteroids.txt','r')
  outFileD=open('distance.txt','w')
  x= (_x**2)
  y= (_y**2) #these three variables I need to pull from readast
  z= (_z**2)
  ...

but I think you need to think again the solution, you could make a function like this:

def equation(x, y,z):
   return math.sqrt(math.pow(x,2)+math.pow(y,2)+math.pow(z,2))

and then call it when you right the first file

astlist=[]*size_of_array
for i in range(0,size_of_array):
    x=random.randint(1,1000)
    y=random.randint(1,1000)
    z=random.randint(1,1000)
    outFileA.write ('\n'+chr(letter) + '\t' +str(x)+ '\t' +str(y)+'\t' +str(z)+ '\t' +str(equation(x,y,z)))
    letter= letter+ 1
outFileA.close()