Creating a Function to use for dataframe

Question

How can I create a function that squares the specific column value from a dataframe in pandas?

it should be like as you see below

def func(dataframe,column,value)

You don't need to use a function. You can just do: df['column name'] = df['column name']**2 — Arkadiusz
– Arkadiusz, Commented Mar 3, 2021 at 13:20

Anurag Dabas · Accepted Answer · 2021-03-03 14:41:39Z

1

Suppose you have dataframe named df

Just create a function:-

def pow(data,column,val):
    return data[column]**val

Now just call the function and pass the series,and val as parameter:-

func(df,'col3',2)

Between you can do this without creating a function just by:-

df['column name']**2

edited Mar 3, 2021 at 14:41

answered Mar 3, 2021 at 13:19

Anurag Dabas

24.3k9 gold badges25 silver badges41 bronze badges

Sign up to request clarification or add additional context in comments.

5 Comments

skrtel1503 Over a year ago

Thanks for your answer.. Yes, I have a dataframe called df Your answers work too but i have to define that function as def func(dataframe,column,value)

skrtel1503 Over a year ago

Without using 'value' i figured out how to do it but i couldn't make it with 'value'. It is how it is without 'value' def func(df,column): df[column]=df[column]*df[column] return df

skrtel1503 Over a year ago

Thanks for helping so much but it's still not the one i need :(......your functions has data,val.... i need df,columnname,value

skrtel1503 Over a year ago

Heyyy :).... I did a small change to your last edit and it works... Thanks a lot!!

Anurag Dabas Over a year ago

that's great............btw if this answer helps you then try considering accept this answer thank you:)

MarianD · Accepted Answer · 2021-03-04 00:12:33Z

1

I suppose that you wanted to square only those values in the column column which are equal to value parameter:

def func(dataframe, column, value):
    s = dataframe[column]
    dataframe[column] = s.mask(s == value, lambda x: x**2)

Note:

This function changes the dataframe in place, so in concordance with Python conventions it returns the None value. (Why? Because there is no return statement.)

The explanation:

In the first command (in the body of the function definition) we assign the appropriate column (i.e. a series) to the variable s.
In the second command we apply the method .mask() with 2 arguments:
- The first argument is a condition for using the second argument,
- the second argument is a function (which is used only for elements satisfying the condition given in the first argument).

A test:

>>> df

   A  B  C  D
0  4  4  3  4
1  3  3  4  4
2  4  4  2  2
3  3  2  3  4
4  4  2  4  3

>>> func(df, "D", 4)
>>> df

   A  B  C   D
0  4  4  3  16
1  3  3  4  16
2  4  4  2   2
3  3  2  3  16
4  4  2  4   3

edited Mar 4, 2021 at 0:12

answered Mar 3, 2021 at 23:43

MarianD

14.4k12 gold badges50 silver badges61 bronze badges

1 Comment

MarianD Over a year ago

You're welcome. What should I do when someone answers my question?

Collectives™ on Stack Overflow

Creating a Function to use for dataframe

2 Answers 2

5 Comments

1 Comment

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

5 Comments

1 Comment

Your Answer

Sign up or log in

Post as a guest

Related