Data Structure
Series (1D)
- 시리즈 데이터는 1차원 배열형태라 생각하면된다.
Create Series
import pandas as pd
series = pd.Series([1,2], index = ['a', 'b'])
----------------------------------------------
a 1
b 2
Get Series Value
import pandas as pd
series.values
-------------------
array([1, 2])
Get Values by Index
import pandas as pd
series['a']
series[['b', 'a']]
---------------------
1
b 2
a 1
DataFrame (2D)
- 행과 열이 임의로 정렬되어있는 표 데이터 구조로 행렬구조를 갖고있다.
Create DF
import pandas as pd
dict1 = {'country': ['CH', 'KR'], 'year': [2000,2010]}
df = pd.DataFrame(dict1)
-------------------------------------------------------
country year
0 CH 2000
1 KR 2010
-------------------------------------------------------
df1 = pd.DataFrame(df, index=["row_1","row_2"])
-------------------------------------------------------
country year
row1 CH 2000
row2 KR 2010
Get Columns and Row Names
import pandas as pd
df1.index
df1.columns
----------------------------------
Index(['row1', 'row2'], dtype='object')
Index(['country', 'year'], dtype='object')
Get Values
import pandas as pd
df1.values
-----------------------------
array([['CH', 2000],
['KR', 2010], dtype=object)
Reshaping
import pandas as pd
df = pd.DataFrame(
{"a" : [4, 5, 6],
"b" : [7, 8, 9],
"c" : [10, 11, 12]},
index = [1, 2, 3])
--------------------------
a b c
1 4 7 10
2 5 8 11
3 6 9 12
--------------------------
df.drop(['c'], axis=1)
--------------------------
a b
1 4 7
2 5 8
3 6 9
Group Data
import pandas as pd