本文已参与「新人创作礼」活动，一起开启掘金创作之路。
Trick：纯demo，心在哪里，结果就在那里
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import pandas as pd
data = pd.Series([2,1,3,4,5])
data
data.values
data.index
data[0]
data[0:3]
data1 = pd.Series([1,2,3],index=['first','second','third'])
data1
data1.index
data2 = pd.Series([1,2,3,4],index=list("abcd"))
data2
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a 1
b 2
c 3
d 4
dtype: int64
Series对象的字典属性
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p = {"b":3000,"sh":2800,"gz":'1500',"sz":1200}
p
p_Series = pd.Series(p)
p_Series
#对象可以按照字典的方式索引
p_Series['b']
# 对于字典式索引，切片操作不同于往常习惯，采取了左闭右闭的方式
p_Series["b":"sh"]
pop_series = pd.Series(p,index=['b','sz'])
pop_series
pop_series = pd.Series(p,index=['xian'])
pop_series
s= pd.Series(5,index=[2,3,5,7])
s
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2 5
3 5
5 5
7 5
dtype: int64
DataFrame对象
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# dataframe对象 和sieries对象类似 既可以看作是一个二维数组，也可看做字典的字典
import pandas as pd
import numpy as np
area_dict = {'beijing':300,'shanghai':200,'gz':180}
area = pd.Series(area_dict)
print(area)
pop = pd.Series({'beijing':3000,'shanghai':2900,'gz':1600})
print(pop)
cities = pd.DataFrame({'population':pop,'area':area})
cities
cities.index
cities.values
cities['area']
cities.iloc[0,1]
df = pd.DataFrame([pop,area],index=['population','area']) # 在pandas中行索引叫index，列索引叫columns,此处应该显式指定index
df
data = pd.DataFrame([{'a':i,'b':2*i}for i in range(3)]) #通过一个关于字典的列表创建了df对象
data
data2 = pd.DataFrame(np.random.randint(0,10,(3,2)),columns=list('ab'),index =list('efg'))
print(data2.columns)
print(data2.index)
print(data2)
beijing 300
shanghai 200
gz 180
dtype: int64
beijing 3000
shanghai 2900
gz 1600
dtype: int64
Index(['a', 'b'], dtype='object')
Index(['e', 'f', 'g'], dtype='object')
a b
e 3 8
f 6 3
g 1 4
No output
