best way for substring pandas data frame

Question

Q1

I want to extract the Title of each person from the Name attribute of concat data frame. what is the best way of doing this?

concat['Title'][concat['Title'] == 'Mlle'] = 'Miss'
concat['Title'][concat['Title'] == 'Ms'] = 'Miss'
concat['Title'][concat['Title'] == 'Mme'] = 'Mrs'
concat['Title'][concat['Title'] == 'Dona' or 'Lady'or 'Countess'or'Capt' or 'Col'or'Don'or 'Dr'or 'Major'or 'Rev'or 'Sir'or 'Jonkheer' ] = 'Rare'

Q2

when i run the above code i get this error:

ValueError: The truth value of a Series is ambiguous. Use a.empty, a.bool(), a.item(), a.any() or a.all().

why?

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Refrences

the full problem with datasets : Titanic

Answer 1

Use str.split, and then extract the second item from the resultant list.

In [37]: df['Name'].head()
Out[37]: 
0                              Braund, Mr. Owen Harris
1    Cumings, Mrs. John Bradley (Florence Briggs Th...
2                               Heikkinen, Miss. Laina
3         Futrelle, Mrs. Jacques Heath (Lily May Peel)
4                             Allen, Mr. William Henry
Name: Name, dtype: object

An observation here is that names follow this format: Last Name, Salutation Given Name. We'll split on spaces and extract the Salutation from the split lists using df.apply:

In [38]: df['Title'] = df['Name'].str.split(' ').apply(lambda x: x[1])

In [39]: df['Title'].head()
Out[39]: 
0      Mr.
1     Mrs.
2    Miss.
3     Mrs.
4      Mr.
Name: Title, dtype: object