Put a few things in a row | DSA & Design, Connected

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Home, park, café. That’s a little list of places to visit. Order matters: home comes first. Python gives each place a position, starting at zero.

The positions are 0, 1, and 2. Which place is at position 1?

Let's look

The park. Position 0 is home, so position 1 is the next place.

A little Python, if you want it

stops = ["home", "park", "cafe"]
assert stops[1] == "park"
assert len(stops) == 3

stops[1] asks for one place. len(stops) counts the places. We call the numbered position an index. A list can also contain repeated values.

Put a shop before home. Is the park still at position 1?

Let's try it

No. The park moves to position 2. A position describes where something is now, not a permanent name for it.

Next, visit the places one at a time. Later, a sliding window will look at a small part of a list.