CODEWITHSUNDEEP
pythonpandas
David Wolever
David Wolever

Reputation: 154454

How can I concatenate a Series onto a DataFrame with Pandas?

If I have a DataFrame:

students = pd.DataFrame([
    ['Alex'],
    ['Lauren'],
])

How can I concatenate a Series and create a new DataFrame? For example, I'd like:

>>> marks = pd.Series([.8, .75])
>>> students.concat(marks).values
[['Alex', .8],
 ['Lauren', .75]]

I know that I could use:

students['marks'] = marks

But that would mutate students.

I've tried:

 >>> pd.concat([students, marks])
 …
 AttributeError: 'Series' object has no attribute '_data'

Upvotes: 21

Views: 28400

Answers (3)

jvns
jvns

Reputation: 281

In this case I would normally do

students["marks"] = marks

But pd.concat works as well.

Upvotes: 0

alko
alko

Reputation: 48307

You can convert to DataFrame and concatenate afterwards:

>>> pd.concat([students, pd.DataFrame(marks)], axis=1)
        0     0
0    Alex  0.80
1  Lauren  0.75

Upvotes: 29

qmorgan
qmorgan

Reputation: 4894

To retain your original dataframe, you could first copy the dataframe, and then add the column:

students2 = students.copy(deep=True)
students2['marks'] = marks

Upvotes: 1

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