[Python data analysis] common pandas operations (I)

pandas be based on Numpy structure , It was originally used as a financial data analysis tool, so pandas Good support for time series analysis .
pandas Two kinds of data structures ：Series and DataFrame

One 、Series （index,value）

import pandas as pd
from pandas import Series
# establish Series
obj=Series([4,7,-5,3])
print(obj)

0 4
1 7
2 -5
3 3
dtype: int64

#index
obj.index

RangeIndex(start=0, stop=4, step=1)

#values
obj.values

RangeIndex(start=0, stop=4, step=1)

obj2=Series([4,7,-5,3],index=['3/1','3/2','3/3','3/4'])
print(obj2)

3/1 4
3/2 7
3/3 -5
3/4 3
dtype: int64

obj2.index

Index([‘3/1’, ‘3/2’, ‘3/3’, ‘3/4’], dtype=‘object’)

obj2.values

array([ 4, 7, -5, 3], dtype=int64)

obj2[obj2>0]