英文:
.remove(word) gives "not in the list" right after a check for that word
问题
我之前已经运行过这段代码，我相信错误不是由于其他代码部分失败引起的。我正在编写一个解析器，它会迭代遍历数据框中的每一行，并将一个字符串解析成输出数据框中的多个列。最近我在一个for循环内添加了一些新的行：
for word in words:
word = word.replace("-", " ")
if word in measurement_units:
measurement = word
words.remove(word)
唯一添加的内容是if语句以及之后的内容。现在，我的代码出现了错误：
words.remove(word)
ValueError: list.remove(x): x not in list
这个错误不常见，它在执行了数十万行之后才出现，所以它不可能是完全微不足道的问题 - 显然某种类型的字符串会触发它。我是一个完全的初学者，所以我已经向bing AI提问，它要我按照以下方式写：
words = row.split(" ")
new_words = []
for word in words:
word = word.replace("-", " ")
if word not in measurement_units:
new_words.append(word)
else:
measurement = word
words = new_words
这个方法可以工作，但为什么我需要这样做呢？在我看来，这个问题本来不应该发生 - 我们知道这个词存在，因为“if”语句已经隐式检查了它是否为“”（空字符串），并且在if语句和words.remove之间没有进行删除操作。怎么回事？
没有太多东西可以测试，因为在一个两行的代码片段中你只能写这么多测试，而且因为我有超过一百万行数据，打印每一行或每个单词都不可行。
英文:
I already ran this code before, and I am confident the error is not due to some other code part failing. I am writing a parser that iterates over every row in a dataframe and parses a string into multiple columns in the output dataframe. I recently added a new couple of lines inside a for loop:
for word in words:
word = word.replace("-", " ")
if word in measurement_units:
measurement = word
words.remove(word)
The only added thing is the if statement and what comes after it. Now, my code errors with
words.remove(word)
ValueError: list.remove(x): x not in list
The error is not common, it goes hundreds of thousands of rows before giving this error, so it cannot be something completely trivial - some type of string clearly triggers it. I am a total beginner, so I already asked bing AI and it wants me to write it as:
words = row.split(" ")
new_words = []
for word in words:
word = word.replace("-", " ")
if word not in measurement_units:
new_words.append(word)
else:
measurement = word
words = new_words
Which works, but why do I need to? In my mind, this already should not be happening - we know the word exists, since the "if" statement already implicitly checks if its "", and there is no removal done between the if and the words.remove. What gives?
Not much - there is only so many test you can write in a 2-line snippet, and since I have well over a million rows, printing every row or every word is not feasible.
答案1
得分: 1
Without any sample data to verify this against it looks like you want:
for word in words[:]:
if word.replace('-', ' ') in measurement_units:
words.remove(word)
英文:
Without any sample data to verify this against it looks like you want:
for word in words[:]:
if word.replace('-', ' ') in measurement_units:
words.remove(word)
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