if/elseSuppose you want to classify customers:
spending >= 1000 → VIP
spending >= 500 → Regular
otherwise → Low
You could write a complicated function.
Or:
import numpy as np
df["segment"] = np.select(
[
df["spending"] >= 1000,
df["spending"] >= 500
],
[
"VIP",
"Regular"
],
default="Low"
)
Now the rules are visible directly in the code.
This becomes especially useful when you have several conditions.
