Python 抛出奇怪的 NameError : name is not defined

Question

import networkx as nx #@UnresolvedImport
from networkx.algorithms import bipartite #@UnresolvedImport
from operator import itemgetter
from random import choice

corpus = open('/home/abehl/Desktop/Corpus/songs.wx', 'r')

ALPHA = 1.5
EPSILON = 0.5

song_nodes = []
word_nodes = []    

edges = zip(song_nodes, word_nodes)

B = nx.Graph(edges)
degX,degY = bipartite.degrees(B, word_nodes)

sortedSongNodesByDegree = sorted(degX.iteritems(), key=itemgetter(1))
print sortedSongNodesByDegree

song_nodes2 = []
word_nodes2 = []
Vc = list(set(word_nodes))

edges2 = zip(song_nodes2, word_nodes2)
C= nx.Graph(edges2)

for songDegreeTuple in sortedSongNodesByDegree:
    for i in range(songDegreeTuple[1]):
        connectedNodes = C.neighbors(songDegreeTuple[0])
        VcDash = [element for element in Vc if element not in connectedNodes]
        calculateBestNode(VcDash)

def calculateBestNode(VcDashsR):
    nodeToProbailityDict = {}
    for node in VcDashsR:
        degreeOfNode = bipartite(C, [node])[1][node]
        probabiltyForNode = (degreeOfNode ** ALPHA) + EPSILON
        nodeToProbailityDict[node] = probabiltyForNode

在上面的 python 程序中，即使在程序中定义了函数“calculateBestNode”，python 解释器也会抛出以下错误。我在这里错过了什么吗？

NameError: name 'calculateBestNode' is not defined

请原谅我在这里发布了一个大型程序。

Answer 1

一个Python程序是自上而下执行的，所以在使用之前需要先定义函数。一个常见的替代方法是将所有自动执行的代码放在 main 函数中，并在文件底部添加:

if __name__ == '__main__':
    main()

这还有一个额外的好处，即您现在已经编写了一个可以被其他人导入的模块。