PRG-PY-pandas
pandas インストール
pip3 install pandas
CSV の読み込み
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import pandas as pd
df_names = pd.read_csv('lds9d1.csv', names=('xa','ya','za', 'xg','yg','zg', 'xm', 'ym', 'zm','ROLL','PITCH','YAW', 'degX','degY','DUM'))
print(df_names)
# 漢字コードのエラーが出る場合には
# df_name = pd.read_csv('lds9d1.csv',engine="python",encoding = "shift-jis")
## engine="python",encoding = "shift-jis"
## を追加してみる
Excel ファイルの読み込み
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
import pandas as pd
# df_names = pd.read_csv('corona-kanjajokyou.csv',names=('n0','n1','n2','n3'))
df = pd.read_excel('corona-kanjajokyou.xlsx')
print('dataframeの行数・列数の確認==>\n', df.shape)
print('indexの確認==>\n', df.index)
print('columnの確認==>\n', df.columns)
print('dataframeの各列のデータ型を確認==>\n', df.dtypes)
print(df)
index の指定
import pandas as pd
### df_names = pd.read_csv('lds9d1.csv', names=('xa','ya','za', 'xg','yg','zg', 'xm', 'ym', 'zm','ROLL','PITCH','YAW', 'degX','degY','DUM'))
df1 = pd.read_csv('./D/30.csv',index_col=0)
df2 = pd.read_csv('./D/31.csv',index_col=0)
# df1.columns = ['host', 'count', 'byte']
# df2.columns = ['host', 'count', 'byte']
astype(int) のエラー
# df1['byte']=df1['response_bytes_clf'].astype(int) df1['byte']=pd.to_numeric(df1['response_bytes_clf'],errors='coerce')
文字列変換
df['browser_version'].str.split('.').str[0:2].str.join('.')
print する、行や列を増やす
pd.set_option('display.max_columns', 100)
pd.set_option('display.max_rows', 500)
List を DataFrane に変換
## rows :: Python List ## ss :: pd.DataFrame ### To pd.DataFrame ss = pd.Series(rows)
https://note.nkmk.me/python-pandas-list/
CVSで読んだ 日時（文字列) を DateTime に
pd.to_datetime(df['A'] pd.to_datetime(df['B'], format='%Y年%m月%d日 %H時%M分')
df['X'] = pd.to_datetime(df['A'])