CODEWITHSUNDEEP
pythonpandasdataframe
NewPy
NewPy

Reputation: 663

dataframe row level operation error when append the new calculated value

I have data frame like enter image description here in the CSV.

I want to get enter image description here

I have received error:

 91             return converter(self.iloc[0])
     92         raise TypeError("cannot convert the series to "
---> 93                         "{0}".format(str(converter)))
     94 
     95     wrapper.__name__ = "__{name}__".format(name=converter.__name__)

TypeError: cannot convert the series to

Following is my code

import pandas as pd 
data = pd.read_csv("test.csv")
a=data['a']
b=data['b']
value=sqrt(a**2+b**2)

data['value']=value

Upvotes: 1

Views: 36

Answers (2)

Cicilio
Cicilio

Reputation: 432

Since the sqrt is not an inbuilt function like sum() in python, you need to use packages like Numpy or Math to call the sqrt function.

import numpy as np
np.sqrt(a**2+b**2)

or

import math
math.sqrt(a**2+b**2)

Upvotes: 0

user27286
user27286

Reputation: 486

Method 1

One way is to use list comprehension:

value=[math.sqrt(x**2+y**2) for x,y in zip(a,b)]

Full code example:

import pandas as pd 
import math

data = pd.read_csv("test.csv")
a=data['a']
b=data['b']
value=[math.sqrt(x**2+y**2) for x,y in zip(a,b)] 

data['value']=value

Method 2

Or use numpy here to do the element wise operation.

import numpy as np
...
np.sqrt(..)

So this code works as expected

import pandas as pd 
import numpy as np

data = pd.read_csv("test.csv")
a=data['a']
b=data['b']
value=np.sqrt(a**2+b**2)

data['value']=value

Adds a column with designated value which is element wise square sum of first 2 columns.

Upvotes: 1

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