
Before pandas, it helps to understand plain Python’s core tools. Almost every automation script is built from lists, dictionaries and loops.
In this article
Lists: an ordered column
regions = ["North", "South", "East", "West"]
print(regions[0]) # North (counting starts at 0)
print(len(regions)) # 4
regions.append("Central")
print(regions[-1]) # Central (last item)
A list is like one Excel column: ordered, and you can add, remove and sort items.
Dictionaries: a lookup table
managers = {"North": "Vikram", "South": "Lakshmi", "East": "Priya"}
print(managers["North"]) # Vikram — like VLOOKUP
print(managers.get("West", "None")) # None — IFERROR built in
managers["West"] = "Farhan" # add or update
Loops: do something for every item
sales = [12500, 8400, 15200, 6100]
total = 0
for amount in sales:
total += amount
print(total) # 42200 — like SUM
big = [s for s in sales if s > 10000] # like FILTER
print(big) # [12500, 15200]
Putting them together: totals by region
rows = [("North", 12500), ("South", 8400), ("North", 15200), ("East", 6100)]
totals = {}
for region, amount in rows:
totals[region] = totals.get(region, 0) + amount
print(totals) # {"North": 27700, "South": 8400, "East": 6100} — a pivot table
💡 Python cares about indentation: the lines inside a loop must be indented the same amount (4 spaces is standard).
Next step: pandas for Excel users, which does all of this on whole tables.