Python TypeError：序列项0：预期的str实例，发现NoneType [英] Python TypeError: sequence item 0: expected str instance, NoneType found

问题描述

我从一本书中复制了以下代码：

I copied this code from a book:

lyst = {'Hi':'Hello'}
def changeWord(sentence):
    def getWord(word):
        lyst.get(word, word)
    return ''.join(map(getWord, sentence.split()))

我收到此错误：

Traceback (most recent call last):
  File "<pyshell#4>", line 1, in <module>
    cambiaPronome('ciao')
  File "C:\Python33\2.py", line 6, in cambiaPronome
    return ''.join(map(getWord, list(frase)))
TypeError: sequence item 0: expected str instance, NoneType found

什么是

推荐答案

getWord 函数未明确返回任何内容，因此它隐式返回 None 。尝试返回一些东西，例如：

The getWord function doesn't explicitly return anything, so it implicitly returns None. Try returning something, e.g.:

def getWord(word):
    return lyst.get(word, word)

这篇关于Python TypeError：序列项0：预期的str实例，发现NoneType的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！