Inserting data into a cell in pandas

Question

I have a dataframe of people and rather than editing it in excel I would like to be able to enter data in pandas directly.

In the example table below, John has nothin in df['Group']

DF

	Name	ID	Grade	Group
0	John	001	89	Nan
1	Jane	002	56	Group 1
2	Joan	003	91	Group 2
3	David	004	45	Group 1

I'd like to be able to change this to 'Group 4', preferably without using iloc (it's a big-ish df).

	Name	ID	Grade	Group
0	John	001	89	Group 4
1	Jane	002	56	Group 1
2	Joan	003	91	Group 2
3	David	004	45	Group 1

I have tried

df.loc[df['Name'] == 'John']['Group'] = 'Group 4'

df2.loc[0,'Group'] = 'Group 4'

These don't work (probably obvious to you).

Is there a way to do this?

Answer 1

For assigning new variables in pandas you can use either loc or at method by having name of the labels:

loc method:

df.loc[df['name'] == 'John', 'Group'] = 'Group 4'

at method(Caveat:at can only access a single value at a time)

df.at[df['name'] == 'John', 'Group'] = 'Group 4'
# **OR**
df.at[0, 'Group'] = 'Group 4'