import pandas as pd
import numpy as np

df = pd.read_excel("http://kanggc.iptime.org/book/data/sample1-n.xlsx")
df.head()
print("Data Frame of df is : ",f'\n{df.head()}\n')

# yearly time series starting from 2000 to 2016:
# df.index = pd.date_range(start='2000', end='2017', freq='Y').year
# df.head()
# print("Data Frame of df is : ",f'\n{df.head()}\n')

year = df['year']
year
gdp = df['gdp']
gdp
consume = df['consumption']
consume

# 자연로그 변수 만들기
lgdp = np.log(gdp) # numpy packaage의 log 활용
lgdp.head()
print("Data of log(gdp) is : ",f'\n{lgdp.head()}\n')

lconsume = np.log(consume) # numpy packaage의 log 활용
lconsume.head()
print("Data of log(consume) is : ",f'\n{lconsume.head()}\n')

# 단일 변수명 바꾸기
df_new = df.rename(columns = {'consumption' : 'cons'} ) # consumption을 cons로 수정
df_new

# 복수 변수명 바꾸기
df_all = df.rename(columns = {'gdp':'y', 'consumption' : 'c'} ) # gdp 및 consumption을 y 및 c로 수정
df_all