学习Pandas，第 6 课

英文原文: 06 - Lesson

我们看一下 groupby 这个函数。

# 导入库
import pandas as pd
import sys

print('Python version ' + sys.version)
print('Pandas version ' + pd.__version__)

Python version 3.6.1 | packaged by conda-forge | (default, Mar 23 2017, 21:57:00) 
[GCC 4.2.1 Compatible Apple LLVM 6.1.0 (clang-602.0.53)]
Pandas version 0.19.2

# 我们的小数聚集
d = {'one':[1,1,1,1,1],
     'two':[2,2,2,2,2],
     'letter':['a','a','b','b','c']}

# 创建一个 dataframe
df = pd.DataFrame(d)
df

	letter	one	two
0	a	1	2
1	a	1	2
2	b	1	2
3	b	1	2
4	c	1	2

# 创建一个 groupby 对象
one = df.groupby('letter')

# 在分组上应用 sum() 函数
one.sum()

	one	two
letter
a	2	4
b	2	4
c	1	2

letterone = df.groupby(['letter','one']).sum()
letterone

		two
letter	one
a	1	4
b	1	4
c	1	2

letterone.index

MultiIndex(levels=[['a', 'b', 'c'], [1]],
           labels=[[0, 1, 2], [0, 0, 0]],
           names=['letter', 'one'])

你可能不想把用来分组的列名字作为索引，像下面的做法很容易实现。

letterone = df.groupby(['letter','one'], as_index=False).sum()
letterone

	letter	one	two
0	a	1	4
1	b	1	4
2	c	1	2

letterone.index

Int64Index([0, 1, 2], dtype='int64')

This tutorial was created by HEDARO

本教程由派兰数据翻译

These tutorials are also available through an email course, please visit http://www.hedaro.com/pandas-tutorial to sign up today.

06 - Lesson

学习Pandas，第 6 课

results matching ""

No results matching ""