pandas 将一列字符串转换为熊猫中的列表
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Convert a columns of string to list in pandas
提问by Guido Muscioni
I have a problem with the type of one of my column in a pandas dataframe. Basically the column is saved in a csv file as a string, and I wanna use it as a tuple to be able to convert it in a list of numbers. Following there is a very simple csv:
我对 Pandas 数据框中的某一列的类型有疑问。基本上，该列作为字符串保存在 csv 文件中，我想将其用作元组，以便能够将其转换为数字列表。下面是一个非常简单的csv：
ID,LABELS
1,"(1.0,2.0,2.0,3.0,3.0,1.0,4.0)"
2,"(1.0,2.0,2.0,3.0,3.0,1.0,4.0)"
If a load it with the function "read_csv" I get a list of strings. I have tried to convert to a list, but I get the list version of a string:
如果使用函数“read_csv”加载它，我会得到一个字符串列表。我试图转换为列表，但我得到了字符串的列表版本：
df.LABELS.apply(lambda x: list(x))
returns:
返回：
['(','1','.','0',.,.,.,.,.,'4','.','0',')']
Any idea on how to be able to do it?
关于如何做到这一点的任何想法？
Thank you.
谢谢你。
回答by jezrael
回答by llllllllll
You can use ast.literal_eval, which will give you a tuple:
你可以使用ast.literal_eval，它会给你一个元组：
import ast
df.LABELS = df.LABELS.apply(ast.literal_eval)
If you do want a list, use:
如果您确实想要一个列表，请使用：
df.LABELS.apply(lambda s: list(ast.literal_eval(s)))
回答by sacuL
You can try this (assuming your csvis called filename.csv):
你可以试试这个（假设你csv被称为filename.csv）：
df = pd.read_csv('filename.csv')
df['LABELS'] = df.LABELS.apply(lambda x: x.strip('()').split(','))
>>> df
ID LABELS
0 1 [1.0, 2.0, 2.0, 3.0, 3.0, 1.0, 4.0]
1 2 [1.0, 2.0, 2.0, 3.0, 3.0, 1.0, 4.0]
回答by Yaakov Bressler
Alternatively, you might consider regular expressions:
或者，您可以考虑正则表达式：
pattern = re.compile("[0-9]\.[0-9]")
df.LABELS.apply(pattern.findall)
