为什么这个 python 代码不起作用（可能是语法错误？）

Question

I am new to python and cannot understand why the method, goSouthWest, is not working with my tester. Both files are located in the same folder. The issue that arises is "goSouthWest is not defined". Basically a name error when calling the goSouthWest function in getPath function. Could someone please tell me what's wrong with my code? The tester's contents are as follows.

Tester:

from Map import Map  

map1 = Map(10, 10) 

print(map1.getPath(5, 5, 4, 1))

Class:

import math

class Map:

    def __init__(self, row, column):
        self.row = row
        self.column = column

    def getPath(self, startRow, startCol, destRow, destCol):
        if startRow < 0 or startRow > self.row or startCol < 0 or startCol > self.column or destRow < 0 or destRow > self.row or destCol < 0 or destCol > self.column:
            raise ValueError("IllegalArgumentException")
        elif (startRow >= destRow and startCol >= destCol):
            path = goSouthWest(startRow, startCol, destRow, destCol)
        return path

    def goSouthWest(startRow, startCol, destRow, destCol): # goSouthWest method
        colDiff = startCol - destCol
        rowDiff = startRow - destRow
        if (colDiff > rowDiff) and (startRow != destRow):
            startRow -= 1
            path = path + "(" + str(startRow) + "," + str(startCol) + ") "
        elif (rowDiff > colDiff) and (startCol != destCol):
            startCol -= 1
            path = path + "(" + str(startRow) + "," + str(startCol) + ") "
        elif (rowDiff > colDiff) and (startCol == destCol):
            startRow -= 1
            path = path + "(" + str(startRow) + "," + str(startCol) + ") "
        elif (colDiff > rowDiff) and (startRow == destRow):
            startCol -= 1
            path = path + "(" + str(startRow) + "," + str(startCol) + ") "
        elif (rowDiff == 0) and (colDiff == 0) and (destRow == 0) and (destCol == 0):
            startCol += 1
            path = path + "(" + str(startRow) + "," + str(startCol) + ") "
        else:
            startRow -= 1
            path = path + "(" + str(startRow) + "," + str(startCol) + ") "

        if startCol != destCol and startRow != destRow:
            path = path + goSouthWest(startRow, startCol, destRow, destCol)

        return path

Answer 1

You don't have the argument self in goSouthWest . Also, you should call member functions as self.function() , like path = self.goSouthWest(startRow, startCol, destRow, destCol)

Answer 2

Your code should be like this:

import math

class Map:

    def __init__(self, row, column):
        self.row = row
        self.column = column

    def getPath(self, startRow, startCol, destRow, destCol):
        if startRow < 0 or startRow > self.row or startCol < 0 or startCol > self.column or destRow < 0 or destRow > self.row or destCol < 0 or destCol > self.column:
            raise ValueError("IllegalArgumentException")
        elif (startRow >= destRow and startCol >= destCol):
            path = goSouthWest(startRow, startCol, destRow, destCol)
        return path
                    # every method of a class must have a self argument
    def goSouthWest(self, startRow, startCol, destRow, destCol):
        colDiff = startCol - destCol
        rowDiff = startRow - destRow
        if (colDiff > rowDiff) and (startRow != destRow):
            startRow -= 1
            path = path + "(" + str(startRow) + "," + str(startCol) + ") "
        elif (rowDiff > colDiff) and (startCol != destCol):
            startCol -= 1
            path = path + "(" + str(startRow) + "," + str(startCol) + ") "
        elif (rowDiff > colDiff) and (startCol == destCol):
            startRow -= 1
            path = path + "(" + str(startRow) + "," + str(startCol) + ") "
        elif (colDiff > rowDiff) and (startRow == destRow):
            startCol -= 1
            path = path + "(" + str(startRow) + "," + str(startCol) + ") "
        elif (rowDiff == 0) and (colDiff == 0) and (destRow == 0) and (destCol == 0):
            startCol += 1
            path = path + "(" + str(startRow) + "," + str(startCol) + ") "
        else:
            startRow -= 1
            path = path + "(" + str(startRow) + "," + str(startCol) + ") "

        if startCol != destCol and startRow != destRow:
                          # methods of the class must be called with self
            path = path + self.goSouthWest(startRow, startCol, destRow, destCol)

        return path