DataFrame操作大全（持續更新）

新建

方法1: 字典創建

from pandas import DataFrame
data = {
        'name':['zs','ls','ww'],
        'age':[10,20,30],
        'sex':['m','w','m']
        }
d = DataFrame(data)

   age name sex
0   10   zs   m
1   20   ls   w
2   30   ww   m

 

方法2：數組創建

import numpy as np
import pandas as pd
ar = np.random.rand(9).reshape(3,3)
df1 = pd.DataFrame(ar)
print(df1)
df2 = pd.DataFrame(ar, index = ["a","b","c"], columns = ["one", "two", "three"])
print(df2)

          0         1         2
0  0.646752  0.405649  0.717825
1  0.202191  0.907458  0.590119
2  0.347748  0.999144  0.329197
        one       two     three
a  0.646752  0.405649  0.717825
b  0.202191  0.907458  0.590119
c  0.347748  0.999144  0.329197

更詳細的：https://blog.csdn.net/u010199356/article/details/85697860

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CSV文件讀寫

假設已經有DataFrame的存在了，

寫CSV文件： data.to_csv(file_name,index = False)

讀CSV文件：data = pd.read_csv(file_name)

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修改

修改列名

方法1：

>>>a.columns = ['a','b','c']
>>>a
   a  b  c
0  1  4  7
1  2  5  8
2  3  6  9

方法二：

>>>a.rename(columns={'A':'a', 'B':'b', 'C':'c'}, inplace = True)
>>>a
   a  b  c
0  1  4  7
1  2  5  8
2  3  6  9

 

增減

 

運算