using len() in Pandas dataframe

Question

This is the look of my DataFrame:

   StateAb    GivenNm    Surname                  PartyNm PartyAb  ElectedOrder
35      WA        Joe    BULLOCK            


        

Answer 1

The correct way to filter a DataFrame based on the length of strings in a column is

df[df['Surname'].str.len() > 9]

df['Surname'].str.len() creates a Series of lengths for the surname column and df[df['Surname'].str.len() > 9] filters out the ones less than or equal to 9. What you did is to check the length of the Series itself (how many rows it has).

Answer 2

Have a look at the python filter function. It does exactly what you want.

df = [
    {"Surname": "Bullock-ish"},
    {"Surname": "Cash"},
    {"Surname": "Reynolds"},
]
longnames = list(filter(lambda s: len(s["Surname"]) > 9, df))
print(longnames)

>>[{'Surname': 'Bullock-ish'}]

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