Python3.5 Pandas模块之Series用法实例分析
作者:loveliuzz
本文实例讲述了Python3.5 Pandas模块之Series用法。分享给大家供大家参考,具体如下:
1、Pandas模块引入与基本数据结构
2、Series的创建
#!/usr/bin/env python # -*- coding:utf-8 -*- # Author:ZhengzhengLiu #模块引入 import numpy as np import pandas as pd from pandas import Series,DataFrame #1.Series通过numpy一维数组创建 print("=========Series通过numpy一维数组创建==========") arr = np.array([1,2,3,4,5]) s1 = pd.Series(arr) print(s1) print(s1.index) print(s1.values) #2.Series直接通过一维数组创建 print("=========Series直接通过一维数组创建==========") s2 = pd.Series([10.5,20,38,40]) print(s2) #修改索引值 s2.index = ['a','b','c','d'] print(s2) #Series通过一维数组创建,可以在创建的同时自定义索引值, # 也可以之后通过赋值的形式去修改 print("=========Series创建的同时自定义索引值和数据类型==========") s3 = pd.Series(data=[89,78,90,87],dtype=np.float64, index=['语文','数学','英语','科学']) print(s3) #3.Series通过字典创建,字典的键对应索引,值对应数据 print("=========Series通过字典创建==========") dict = {'a':1,'b':2,"c":3,"d":4} s4 = pd.Series(dict) print(s4)
运行结果:
=========Series通过numpy一维数组创建==========
0 1
1 2
2 3
3 4
4 5
dtype: int32
RangeIndex(start=0, stop=5, step=1)
[1 2 3 4 5]
=========Series直接通过一维数组创建==========
0 10.5
1 20.0
2 38.0
3 40.0
dtype: float64
a 10.5
b 20.0
c 38.0
d 40.0
dtype: float64
=========Series创建的同时自定义索引值和数据类型==========
语文 89.0
数学 78.0
英语 90.0
科学 87.0
dtype: float64
=========Series通过字典创建==========
a 1
b 2
c 3
d 4
dtype: int64
3、Series值的获取
#模块引入 import numpy as np import pandas as pd from pandas import Series,DataFrame #4.Series值的获取 print("=========Series值的获取==========") s2 = pd.Series([10.5,20,38,40]) #修改索引值 s2.index = ['a','b','c','d'] print(s2) print(s2[0]) #方括号+下标值的形式获取Series值 print(s2["a"]) #方括号+索引的形式获取Series值
运行结果:
=========Series值的获取==========
a 10.5
b 20.0
c 38.0
d 40.0
dtype: float64
10.5
10.5
4、Series运算
#模块引入 import numpy as np import pandas as pd from pandas import Series,DataFrame #5.Series值的运算 #Series中元素级别的运算结果,包含索引值并且键值关系保持不变 print("=========Series值的运算==========") s6 = pd.Series({'a':1,'b':2,"c":3,"d":4}) print(s6) print("=========打印Series大于2的值==========") print(s6[s6>2]) print("=========打印Series的值除以2==========") print(s6/2) #numpy中的通用函数在Series中也支持 s7= pd.Series([1,2,-3,-4]) print(np.exp(s7))
运行结果:
=========Series值的运算==========
a 1
b 2
c 3
d 4
dtype: int64
=========打印Series大于2的值==========
c 3
d 4
dtype: int64
=========打印Series的值除以2==========
a 0.5
b 1.0
c 1.5
d 2.0
dtype: float64
0 2.718282
1 7.389056
2 0.049787
3 0.018316
dtype: float64
5、Series缺失值检验
#模块引入 import numpy as np import pandas as pd from pandas import Series,DataFrame #6.Series缺失值检验 scores = Series({"a":88,"b":79,"c":98,"d":100}) print(scores) new = ["a","b","e","c","d"] scores = Series(scores,index=new) print(scores) print("======过滤出为缺失值的项=======") print(scores.isnull()) #NAN值返回True #print(pd.isnull(scores)) #与上面一句等价 print("======过滤出为非缺失值的项=======") print(pd.notnull(scores)) #非NAN值返回True
运行结果:
a 88
b 79
c 98
d 100
dtype: int64
a 88.0
b 79.0
e NaN
c 98.0
d 100.0
dtype: float64
======过滤出为缺失值的项=======
a False
b False
e True
c False
d False
dtype: bool
======过滤出为非缺失值的项=======
a True
b True
e False
c True
d True
dtype: bool
6、Series自动对齐
#模块引入 import numpy as np import pandas as pd from pandas import Series,DataFrame #7.Series自动对齐 s8 = Series([12,28,46],index=["p1","p2","p3"]) s9 = Series([2,4,6,8],index=["p2","p3","p4","p5"]) print("=======s8=======") print(s8) print("=======s9=======") print(s9) print("=======s8+s9=======") print(s8+s9)
运行结果:
=======s8=======
p1 12
p2 28
p3 46
dtype: int64
=======s9=======
p2 2
p3 4
p4 6
p5 8
dtype: int64
=======s8+s9=======
p1 NaN
p2 30.0
p3 50.0
p4 NaN
p5 NaN
dtype: float64
7、Series及其索引的name属性
#模块引入 import numpy as np import pandas as pd from pandas import Series,DataFrame #8.Series及其name属性 s10 = Series({"jack":18,"amy":20,"lili":23,"susan":15}) print(s10) print("=======设置name属性后=======") s10.name = "年龄" #数据名称标签 s10.index.name = "姓名" #索引名称标签 print(s10)
运行结果:
amy 20
jack 18
lili 23
susan 15
dtype: int64
=======设置name属性后=======
姓名
amy 20
jack 18
lili 23
susan 15
Name: 年龄, dtype: int64
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