Pandas limit Series/DataFrame to range of values of one column

Question

I’d like to have a function df_out(df_in,val_min,val_max) that makes a sorted series/dataframe from another series/dataframe by picking rows where values in one column are within a defined range. E.g., if df_in looks like this:

Name   Age

John  13

Jack  19

Sylvia 21

Anna 14

Carlos 15

Vladimir 30

Gustav 28

Amie 24

I’d like df_out(18,25) to look like this:

Name Age

Jack 19

Sylvia 21

Amie 24

What's the most "pythonic" way to do this? Thanks!

Answer 1

Why use a function when it is so easily done natively?

>>> df[df.Age.between(18, 25)]
     Name  Age
1    Jack   19
2  Sylvia   21
7    Amie   24

>>> df[df.Age.between(19, 24, inclusive=False)]
     Name  Age
2  Sylvia   21

Answer 2

Once you have it in a DataFrame df, with columns Name, and Age, you can simply use

df[(min_val <= df.Age) & (df.Age <= max_val)]

Note that you need to use the seemingly-redundant parentheses in the above expression, due to operator precedence.

---

You can create this into a function like so:

def df_limited(df, min_val, max_val):
    return df[(min_val <= df.Age) & (df.Age <= max_val)]