pandas-apply-lambda

pandas官方文档

import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
%matplotlib inline

df = pd.read_csv('bookManage.csv')
df.info()

RangeIndex: 200 entries, 0 to 199
Data columns (total 6 columns):
 #   Column  Non-Null Count  Dtype  
---  ------  --------------  -----  
 0   id      200 non-null    int64  
 1   书名      200 non-null    object 
 2   类型      200 non-null    object 
 3   作者      200 non-null    object 
 4   价格      200 non-null    float64
 5   上架时间    200 non-null    object 
dtypes: float64(1), int64(1), object(4)
memory usage: 9.5+ KB

df.head()

# 加一个特征 价格区间 分为便宜，中等，昂贵
df['rate'] = df.价格
df

def getRate(x):
    if x >= 100:
        return "昂贵"
    if x <= 50:
        return "便宜"
    if x > 50 and x < 100:
        return "中等"

df.rate = df.rate.apply(lambda x:getRate(x))

df