python-3.x - 按列名获取行值

Question

我有以下数据框:

🐍 >>> data = {'seasons': ['season_2', 'season_3', 'season_4', 'season_5', 'season_6', 'season_7', 'season_1']}
🐍 >>> df = pd.DataFrame(data)
🐍 >>> df['season_1'] = 1
🐍 >>> df['season_2'] = 2
🐍 >>> df['season_3'] = 3
🐍 >>> df['season_4'] = 4
🐍 >>> df['season_5'] = 5
🐍 >>> df['season_6'] = 6
🐍 >>> df['season_7'] = 7
🐍 >>>
🐍 >>> df
    seasons  season_1  season_2  season_3  season_4  season_5  season_6  season_7
0  season_2         1         2         3         4         5         6         7
1  season_3         1         2         3         4         5         6         7
2  season_4         1         2         3         4         5         6         7
3  season_5         1         2         3         4         5         6         7
4  season_6         1         2         3         4         5         6         7
5  season_7         1         2         3         4         5         6         7
6  season_1         1         2         3         4         5         6         7

如何为给定行创建一个新列，该列的值在 seasons 中指定？例如我希望 season_values 的值为:

season_values = [2, 3, 4, 5, 6, 7, 1]

Answer 1

尝试:

df = df.assign(season_values = df.apply(lambda x: x[x['seasons']],1))
# df['season_values'] = df.apply(lambda x: x[x['seasons']],1)

通过 melt 的另一个选项:

melt = df.melt(['seasons'], ignore_index=False)
df['season_value'] = melt.loc[melt['seasons'] == melt['variable']]