finding dupes (with a twist)

[Lyle]

Hi, buran.

Still on my to do list is to dissect this line from your code:

df['Email'] = df['Email'].apply(lambda x: x.lower())

However, I in my travels, I have recently come across this approach:

df['Email'] = df['Email'].str.lower()

which is much easier for me to grasp.

What would you say are the relative pros & cons of each approach?