Is there syntactic sugar for rewriting pandas column values?

Question

For example I lets say I have the dataframe df with column A containing ints.

If I wanted to change all the values in A so that they all had 1 added to them I would write something like this:

df["A"] = df["A"] + 1

Is there a way to write this so I don't have to write df["A"] twice?

Yes, `df["A"] += 1`. See https://stackoverflow.com/questions/4841436/what-exactly-does-do-in-python — Zero, Sep 26 '17 at 17:42
also `df.A.add(1)` is worth mentioned, although `df.A += 1` is better. — Mohamed Ali JAMAOUI, Sep 26 '17 at 19:19

score 3 · Accepted Answer · answered Sep 26 '17 at 20:10

_{Most of these solutions have been mentioned in comments, so I'm just fleshing them out as answers here.}

Option 1
Direct assignment. The most idiomatic approach.

df['A'] += 1

Alternatively, you could use the dot notation for accessing columns:

df.A += 1

This, however, will not work for columns that have spaces in them, or begin with digits.

Option 2
Using df.assign _{(better if you want a copy, rather than inplace assignment)}

df = df.assign(A=df['A'] + 1)

You can also use this in conjunction with df.add as pointed out:

df = df.assign(A=df['A'].add(1))

1 Answers1