Python_DataFrame_常用操作

DataFrame   数据常用操作 operations

import pandas as pd
import numpy as np

df1=pd.DataFrame({
'name':['a','b','c','d','a'],
'age':[20,18,17,16,15],
'class':[2000,2001,2000,2002,2000],
'score':[99,100,97,87,95]
})

In [6]:

df1.mean()           # 平均值

Out[6]:

age        17.2
class    2000.6
score      95.6
dtype: float64


In [7]:

df1['age'].mean()  #指定列平均值


Out[7]:

17.2

In [8]:


df1[['age','score']].mean()  #指定列平均值


Out[8]:

age      17.2
score    95.6
dtype: float64


In [9]:


df1.sum()

Out[9]:

name     abcda
age         86
class    10003
score      478
dtype: object


In [10]:

df1[['age','score']].sum()

Out[10]:

age       86
score    478
d