DataFrame 行・列の追加

行を追加

DataFrame型のdfに対して下記を実行

df.append("Series型のデータ", ignore_index = True)

import pandas as pd

fruits = ["apple", "orange", "banana", "strawberry"]
data1 = [10, 5, 8, 12]
data2 = [30, 25, 12, 10]
data3 = [30, 12, 10, 8, 3]
series1 = pd.Series(data1, index = fruits)
series2 = pd.Series(data2, index = fruits)

fruits.append("pineapple")
series3 = pd.Series(data3, index = fruits)

df = pd.DataFrame([series1, series2])
df = df.append(series3, ignore_index = True)

df.index = ["1", "2", "3"]
display(df)

補足

元々のカラムと追加するSeries型のデータのインデックスが一致しない場合は、値が存在しない要素にNanが埋め込まれる。

列を追加

DataFrame型の変数dfに対して下記を実行

df["新しいカラム”] = "Seriesもしくはリスト"

import pandas as pd

fruits = ["apple", "orange", "banana", "strawberry"]
data1 = [10, 5, 8, 12]
data2 = [30, 25, 12, 10]
series1 = pd.Series(data1, index = fruits)
series2 = pd.Series(data2, index = fruits)

new_colum = pd.Series([15, 7], index = [0, 1])

df = pd.DataFrame([series1, series2])
display(df)

df["mango"] = new_colum

display(df)