为什么会收到ValueError？

Question

我有两个看起来完全相同的文件：file1

1 in seattle today the secretary of education richard riley delivered his address 
1 one of the things he focused on as the president had done
1 abc's michele norris has been investigating this
2 we're going to take a closer look tonight at the difficulty of getting meaningful

文件2

1 in seattl today the secretari of educ richard riley deliv hi address
1 one of the thing he focus on a the presid had done
1 abc michel norri ha been investig thi 
2 we'r go to take a closer look tonight at the difficulti of get meaning

当我运行此代码时：

result=defaultdict(list)
with open("onthis.txt","r") as filer:
    for line in filer:
        label, sentence= line.strip().split(' ', 1)
        result[label].append(sentence)

它完全适合file1，但给我file2值错误：

label, sentence= line.strip().split(' ', 1)
ValueError: need more than 1 value to unpack

当它们都采用相同的格式时，我似乎并没有抓住原因。 因此，我通过此终端命令删除了空行：

sed '/^$/d' onthis.txt > trial

但是出现相同的错误。

Answer 1

它们不能完全相同。 我的猜测是您的第二个文件中某处有一个空/仅空白行，最有可能在结尾处。

错误告诉您，当执行拆分时，没有空格可拆分，因此仅返回一个值，而不是label和sentence的值。

Answer 2

根据您的编辑，我怀疑您的文本文件中可能仍然有“空”行。 好吧，我可能最好说：除了空白以外，什么都没有填充的行。

我扩展了您的示例文件：

1 in seattl today the secretari of educ richard riley deliv hi address
1 one of the thing he focus on a the presid had done
1 abc michel norri ha been investig thi 
2 we'r go to take a closer look tonight at the difficulti of get meaning
 3   foo

4 bar


5 qun

可能还不清楚，但是3 foo和4 bar之间的行由几个空格填充，而4 bar 5 qun之间的行“只是”新行（ \\n ）。

注意sed '/^$/d'

1 in seattl today the secretari of educ richard riley deliv hi address
1 one of the thing he focus on a the presid had done
1 abc michel norri ha been investig thi 
2 we'r go to take a closer look tonight at the difficulti of get meaning
 3   foo

4 bar
5 qun

空行确实被删除了-毫无疑问。 但是伪空的空白行仍然存在。 到达此行时，运行python脚本将引发错误：

2 we'r go to take a closer look tonight at the difficulti of get meaning

 3   foo    

Traceback (most recent call last):
  File "python.py", line 9, in <module>
    label, sentence= line.strip().split(' ', 1)
ValueError: need more than 1 value to unpack

因此，我的建议是将脚本扩展一行，使其跳过输入文件中的空行。

for line in filer:
    if not line.strip(): continue

这样做会产生积极的副作用，您不必事先使用sed -magic准备输入文件。

Answer 3

根据以上提供的内容（进行了调整）。 这似乎给出了预期的结果。

result = {}

with open("test.txt", "r") as filer:
    for line in filer:
        label, sentence = line.strip().split(' ', 1)
        try:
            result[label].append(sentence)
        except KeyError:
            result[label] = [sentence]

输出：

{'2': ["we'r go to take a closer look tonight at the difficulti of get meaning"], '1': ['in seattl today the secretari of educ richard riley deliv hi address', 'one of the thing he focus on a the presid had done', 'abc michel norri ha been investig thi']}

因此，这必须表示我们所提供的内容中缺少某些内容。 我认为，如果以上内容无法满足您的需求，则需要更多信息