pandas sum rows
# Basic syntax:
df.sum(axis=1)
# Create new column consisting of row sums across specific columns:
df['sums'] = df.iloc[:, 6:23].sum(axis=1)
# Where:
# - iloc allows you to specify the rows and columns with slicing. Here
# I select all rows and sum over columns 6-22
# - df['sums'] is how you assign a new column named 'sums' to the df
# Example usage:
import pandas as pd
import numpy as np
# Create dataframe:
df = pd.DataFrame(np.array([[1, 2, 3], [4, 5, 6], [7, 8, 9]]),
columns=['a', 'b', 'c'])
print(df)
a b c
0 1 2 3
1 4 5 6
2 7 8 9
# Sum columns 1-2:
df['sums'] = df.iloc[:, 1:3].sum(axis=1)
print(df)
a b c sums
0 1 2 3 5
1 4 5 6 11
2 7 8 9 17