Pandas：数据变形

import pandas as pd
data = {'ID':[1,2],'name':['alice','bob'],'Math':[90,85],'English':[88,92],'Science':[95,89]
}
df = pd.DataFrame(data)
df

行列转置
df.T

宽表转换成长表

pd.melt(df,id_vars = ['ID','name'],var_name = "科目",value_name = "分数")

其中id_vars是不变的列

长表转宽表

df2 = pd.melt(df,id_vars = ['ID','name'],var_name = "科目",value_name = "分数")
df2
pd.pivot(df2,index = ['ID','name'],columns = "科目",values = "分数")

分裂操作

import pandas as pd
data = {'ID':[1,2],'name':['alice smith','bob smith'],'Math':[90,85],'English':[88,92],'Science':[95,89]
}
df = pd.DataFrame(data)
df

df[['firstName','lastName']] = df['name'].str.split(" ",expand = True)
df

分裂下面的blood_pressure

df = pd.read_csv("D:\BaiduNetdiskDownload\data\sleep.csv")
df

数据链接：

https://download.csdn.net/download/qq_43494013/91336841?spm=1001.2014.3001.5503

df[['high_pressure','low_pressure']] = df['blood_pressure'].str.split("/",expand = True)
df