import pandas as pd
import time
# Make a bigger dataset
df_big = pd.DataFrame({
"product": ["A", "B", "C", "D", "E"] * 100_000,
"sales": [500, 1200, 800, 2000, 300] * 100_000
})

# Time the loop
start = time.time()
for i in range(len(df_big)):
if df_big.loc[i, "sales"] > 1000:
df_big.loc[i, "tier"] = "high"
else:
df_big.loc[i, "tier"] = "low"
end = time.time()
print("Loop time:", end - start)