使用Lambda函数进行精确的字符串搜索

Question

How can one search for exact string using a lambda function? The data frame looks as follows:

A  B     
10 Mini 

20 Mini Van

15 Mini

13 Mini Bus

Desired results

A   B

10  Mini

15  Mini

I have tried the following, but all fail:

df_temp = df_temp[df_temp['B'].apply(lambda x: 'mini' in x)] and
df_temp = df_temp[df_temp['B'].apply(lambda x: 'mini' in x.str.match())]

Thank you

Answer 1

Just check for equality:

df_temp = df_temp[df_temp['B'] == 'Mini']

This works because df_temp['B'] == 'Mini' returns a Boolean series, which is then used to index df_temp .

Or you can use pd.DataFrame.query for more intuitive syntax:

df_temp = df_temp.query('B == "Mini"')

pd.Series.apply is just a thinly veiled loop; it should be reserved for when you need to explicitly operate on a series one item at a time in a loop. It is inefficient and verbose versus indexing via the above methods.