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Day 7 — Python for loops and range()

The whole point of programming: do the same thing to a thousand rows without writing it a thousand times.

Looping over a list

city is just a name you chose. Python fills it with each item in turn.

range()

It starts at 0 and stops before the number you give — five numbers, 0 to 4.

Building a total

This pattern — start at zero, add each item — is the foundation of every report you will write.

Filtering inside a loop

enumerate() when you need the position

zip() to walk two lists together

Looping over rows

Real data is usually a list of rows. Unpack each row as you go.

Try these yourself

Print the numbers 1 to 10.
Print only the even numbers up to 20.
Total a list of prices with a loop.
Print each name in a list with its position, starting from 1.
Loop over rows of (name, amount) and print only those above 40000.

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