Search⌘ K
Home/
Courses/
Pandas Brain Teasers

Relational Operators with Pandas Series

Let's find out why the puzzle gives a ValueError and how we can fix it.

We'll cover the following...

Try it yourself

Try executing the code below to see the result.

Python 3.5
import pandas as pd
def relu(n):
  if n < 0:
    return 0
  return n
    
arr = pd.Series([-1, 0, 1])
print(relu(arr))

Explanation

The problematic line is if n < 0:. Here n is the result of arr < 0, which is a pandas.Series.

In [1]: import pandas as pd
In [2]: arr = pd.Series([-1, 0, 1])
In [3]: arr < 0
Out[3]:
0 True
1 False
2 False
dtype: bool

Once arr < 0 is computed, we use it in an if statement because of how Boolean values work in Python. Every Python object, not just True and False, has a Boolean value.

We can test the truth value of a Python object using the built-in bool function. In Python, everything is True except the following:

  • 00
...