pandas小技巧

1. 删除列

import pandas as pd
df.drop("Unnamed: 0", axis=1, inplace=True)

2. 转换列的格式

df["Date"] = df["Date"].astype("datetime64[ns]")
df = df.astype({'trans_time': 'datetime64[ns]', 'store_code'a:int, 'goods_id':int})

3. 数据膨胀

res_eff_gt3['weekday'] = [list(range(7))] * len(res_eff_gt3)
res_eff_gt3.explode('weekday')

4. 字符拆分与切分

df["Name"].str.split(",", expand=True)
# $19,100字符类型转成数值型
df["Payment"] = df["Payment"].str[1:].str.replace(",", ".").astype("float")

5. 正则：字符串替换

想要字母
df["Note"].str.replace('[^a-zA-Z]', '')
# 想要字母和数字
df["Note"].str.replace('[^a-zA-Z0-9]', '')