在 Pandas 中转换读取 csv 的数据 [英] Convert data on reading csv in pandas

问题描述

我正在将 .csv 文件读入 Pandas 数据帧..csv 文件包含多列.列A"包含字符串20-989-98766".加载文件时是否可以只从字符串中读取最后 5 个字符 '98766'?

I'm reading a .csv file into a pandas dataframe. The .csv file contains several columns. Column 'A' contains a string '20-989-98766'. Is it possible to only read the last 5 characters '98766' from the string when loading the file?

df = pd.read_csv("test_data2.csv", column={'A':read the last 5 characters})

输出:

A
98766
95476
.....

推荐答案

您可以定义一个 func 并将其作为参数传递给 converters param for read_csv::>

You can define a func and pass this as an arg to converters param for read_csv:

In [57]:
import io
import pandas as pd
def func(x):
    return x[-5:]
t="""column
'20-989-98766"""
df = pd.read_csv(io.StringIO(t), converters={'column': func})
df

​
Out[57]:
  column
0  98766

所以在这里我定义了一个 func 并将它以 dict 的形式传递给 converters，以您的列名作为键，这将调用 func 在您的 csv 中的每一行

So here I define a func and pass this to converters in the form of a dict with your column name as the key, this will call the func on every row in your csv

因此在您的情况下，以下内容应该有效:

so in your case the following should work:

df = pd.read_csv("test_data2.csv", converters={'A':func})

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