Sorting puts a row of items in a chosen order. Order is what makes a list searchable, comparable, and readable, so sorting is one of the most common steps in a program.
About 2 min of reading
Sort small rows and read the result.
Sort three numbers.
Before you run it, say out loud what it will print. Then open the answer.
Sort high to low.
Before you run it, say out loud what it will print. Then open the answer.
Sort three words.
Before you run it, say out loud what it will print. Then open the answer.
Read the smallest after sorting.
Before you run it, say out loud what it will print. Then open the answer.
Read the first example one line at a time. A line that prints shows what appears on screen; the rest set things up quietly.
Once a list is sorted, every later step assumes it. A search, a merge, and a display all read that order, so the choice of order has to be shared.
Every sorting method works by asking whether one item comes before another. Change the comparison and the same method sorts by something else.
nums = [4, 1, 3]
print(sorted(nums))The row becomes 1, 3, 4. sorted returns a new row in order and leaves the original alone.
print(sorted([4, 1, 3], reverse=True))The same numbers can go low to high or high to low. The order you pick is the contract for everything that reads the list.
print(sorted(["owl", "ant", "bee"]))Words sort by their letters. The rule is the same, only the comparison changes from numbers to letters.
nums = sorted([9, 2, 7])
print(nums[0])Once a row is sorted, the smallest is the first item. Order turns a question into an index.
print(sorted([2, 2, 1]))Equal items stay together. Sorting decides position by comparison, never by luck.
print(sorted([[2, "b"], [1, "a"]]))Pairs sort by their first item, then the second. That is the rule behind sorting by a key.
print(sorted([1, 2, 3]))A row in order sorts to itself. Sorting an ordered row is the cheapest case for every method.
print(sorted([5, 3, 4]))Names, scores, dates, and files are all sorted. The same idea covers all of them.