Python的投掷奇怪NameError：名称<FUNCTION_NAME>没有定义

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 

在上述Python程序，python解释是投掷即使函数“calculateBestNode”在程序被定义下面的错误。我在这里错过了什么。

NameError: name 'calculateBestNode' is not defined

请原谅我在这里发布大型项目。

Answer 1

Python程序是从上到下执行的，因此您需要在使用它之前定义函数。一个常见的替代方案是把所有这一切都在一个main功能自动执行的代码，并在文件末尾添加：

if __name__ == '__main__': 
    main() 

这具有额外的优势，你现在已经写了可以通过导入模块其他。

Answer 2

在您的程序中定义它之前，您尝试使用函数calculateBestNode()。所以解释者不知道它存在。