Pythonで前年同月比を計算する方法【例：CPI】

DataFrame[DataFrame.index.month == 〇〇]

pip install jupyterlab

pip install pandas_datareader

pip install pandas

pip install plotly

import datetime
import pandas_datareader.data as web

#1950年1月～現在
start = datetime.datetime(1950, 1, 1)
end = datetime.datetime.now()
cpi = web.DataReader('CPIAUCNS', 'fred', start, end)
cpi

import plotly
import plotly.express as px

cpi_g = cpi.reset_index()
px.line(cpi_g, x="DATE", y="CPIAUCNS")

import pandas as pd

for i in range(1,13):
    df = cpi[cpi.index.month == i]
    df_diff = df.shift(1)
    df_y = df/df_diff
    if i==1:
        df_y_list = df_y
    else:
        df_y_list = pd.concat([df_y_list,df_y])
        
df_y_list_sorted = df_y_list.sort_index()
df_y_list_sorted

cpi[cpi.index.month == i]

df_y_list_sorted_g = df_y_list_sorted.reset_index()
px.line(df_y_list_sorted_g, x="DATE", y="CPIAUCNS")

DataFrame[DataFrame.index.month == 〇〇]