Find the Maximum Value Across Multiple Columns in Pandas

Suppose you have a dataframe with several columns and wish to create a new column containing the maximum value from two or more existing columns. For instance, given columns A and B, you need to create a column C where:

C = max(A, B)

To accomplish this task:

1. Use the max function along with axis=1 to calculate the maximum value for each row across the specified columns:

df[["A", "B"]].max(axis=1)

2. Assign the result to a new column:

df["C"] = df[["A", "B"]].max(axis=1)

This generates a new column C containing the maximum value for each row between columns A and B:

Note that this technique can be generalized to find the maximum value across any number of columns.