如何使用 Pandas 列表中的值隨機替換列中的值？

Question

我有以下 dataframe：

data = {'Names':['Antonio','Bianca','Chad','Damien','Edward','Frances','George'],'Sport':['Basketball','Placeholder','Football','Placeholder','Tennis','Placeholder','Placeholder']}

df = pd.DataFrame(data, columns = ['Names','Sport'])

我想用以下列表中的任何值隨機替換值“占位符”：

extra_sports = ['Football','Basketball','Tennis','Rowing']

最終結果應該看起來像這樣，其中值“占位符”現在消失了，並隨機替換為列表中的值：

data = {'Names':['Antonio','Bianca','Chad','Damien','Edward','Frances','George'],'Sport':['Basketball','Tennis','Football','Rowing','Tennis','Football','Tennis']}

df = pd.DataFrame(data, columns = ['Names','Sport'])

如果可能的話，我將如何實現 random.seed 以便我可以重現結果。

Answer 1

我相信你只需要用列表替換值Placeholder ，對於列表的長度，使用 boolean True的sum以獲得正確的數組長度：

extra_sports = ['Football','Basketball','Tennis','Rowing']
   
np.random.seed(1) 
m = df['Sport'].eq('Placeholder')
df.loc[m, 'Sport'] = np.random.choice(extra_sports, size=m.sum())
print (df)
     Names       Sport
0  Antonio  Basketball
1   Bianca  Basketball
2     Chad    Football
3   Damien      Rowing
4   Edward      Tennis
5  Frances    Football
6   George    Football