如何使用 Pandas 编辑 CSV 文件中的一列数据？

Question

在我的 CSV 文件中，% Return 列当前是所有字符串。 如何删除 % 符号并使所有值变为浮点数？

CSV 文件示例：

Date,Cash,Cash Interest,Margin Cost,Net Worth,% Return
9/16/2019,"$45.96 ",N/A,N/A,"$36.94 ",38.94%
9/13/2019,"$27.50 ",N/A,N/A,"$39.88 ",39.02%
9/12/2019,"$27.50 ",N/A,N/A,"$38.77 ",39.56%
9/11/2019,"$27.50 ",N/A,N/A,"$33.06 ",39.13%
9/10/2019,"$27.50 ",N/A,N/A,"$34.78 ",35.47%
9/9/2019,"$27.50 ",N/A,N/A,"$35.81 ",34.69%
9/6/2019,"$27.50 ",N/A,N/A,"$32.31 ",33.55%
9/5/2019,"$27.50 ",N/A,N/A,"$35.24 ",33.61%
9/4/2019,"$11.07 ",N/A,N/A,"$30.04 ",30.91%

Answer 1

您可以定义 function 以将百分比值转换为浮点数。 像这样：

import pandas as pd

# define your function to convert
def percent_to_float(x):
    return float(x.strip('%'))/100

#read your csv file, 'col' is your column with percent values
df = pd.read_csv('data.csv', converters={'col':percent_to_float})