Sorting and Ordering

Sorting puts a collection in order. Both languages sort in place or return a new sorted collection, and both let you sort by a rule you define.

Sorting

PYTHON

nums = [5, 2, 9, 1]

print(sorted(nums))     # new list
nums.sort()             # in place
print(nums)

JAVASCRIPT

const nums = [5, 2, 9, 1];

console.log([...nums].sort((a, b) => a - b));
nums.sort((a, b) => a - b);
console.log(nums);

Compare → Python sorts numbers correctly by default. JavaScript's sort converts to text first, so [10, 9] sorts as [10, 9] unless you pass the comparison function (a, b) => a - b. This trips up experienced developers, always pass the comparator for numbers.

EXAMPLE

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YOUR TURN

Your turn → Sort a list of your own test scores from highest to lowest and print it, in both languages.

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Syntax has to be exact. Every quote, bracket and parenthesis needs its partner, and in Python the spaces at the start of a line count. One slip and the program won't run; the message will say where.

Sorting records by one of their fields is the version you will actually use.

EXAMPLE

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YOUR TURN

Your turn → Python names the sort key with a small inline function. JavaScript subtracts to decide order. Flip to ascending in both.

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Syntax has to be exact. Every quote, bracket and parenthesis needs its partner, and in Python the spaces at the start of a line count. One slip and the program won't run; the message will say where.

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