Panda print the mark if the name exists

Question

Name	Mark
Ben	20
James	50
Jimmy	70

I have a dataframe which looks something like this. I wanna check if the name exists and then it will print the mark for that specific person.

if len(df[(df['Name'] == "James")]) != 0:
    print(len(df["Mark"]))

Above is my code. Hope to get some advise!

Answer 1

Better use a Series here with get with a default argument:

marks = df.set_index('Name')['Mark']

marks.get('James', 'missing')
# 50

marks.get('Nonexistent', 'missing')
# missing

Or without default, get returns None:

marks.get('Nonexistent') # no output

Answer 2

You can return the mark of a specified name in your Name column using loc. The below will print the Mark of the name you pass, and will return an empty series if the name does not exist in your Name column:

name_to_retrieve_mark = 'Ben'
df.loc[df.Name.eq(name_to_retrieve_mark),'Mark']

Out[13]: 
0    20
Name: Mark, dtype: int64

---

name_to_retrieve_mark = 'Sophocles'
df.loc[df.Name.eq(name_to_retrieve_mark),'Mark']

Out[15]: Series([], Name: Mark, dtype: int64)