如何将新元素添加到列表的pandas.DataFrame列？

Question

我有一个像这样的pandas.DataFrame ：

id       count        fruit_list
---------------------------------------
0        42           [orange, apple]
1        57           [lemon]
2        86           [kiwi]
3        33           [pineapple, pear]
4        11           [apple, lemon]
...

我需要在每行中将新的字符串添加到fruit_list 。 假设字符串是banana ，所以我需要以这样的DataFrame结尾：

id       count        fruit_list
---------------------------------------
0        42           [orange, apple, banana]
1        57           [lemon, banana]
2        86           [kiwi, banana]
3        33           [pineapple, pear, banana]
4        11           [apple, lemon, banana]
...

请问我如何最容易地做到这一点？

Answer 1

尝试apply ：

df['fruit_list'] = df['fruit_list'].apply(lambda x: x + ['banana'])

样品：

df = pd.DataFrame({'count': [42, 57], 
                   'fruit_list': [['orange', 'apple'], ['lemon']], 
                   'id': [0, 1]}).reindex_axis(['id','count','fruit_list'], 1)
print (df)
   id  count       fruit_list
0   0     42  [orange, apple]
1   1     57          [lemon]

df['fruit_list'] = df['fruit_list'].apply(lambda x: x + ['banana'])
print (df)
   id  count               fruit_list
0   0     42  [orange, apple, banana]
1   1     57          [lemon, banana]