Built-in Functions

Python comes with a bunch of useful functions already built in. We've already seen print(), len(), int(), input(), range(), min(), max(). Let's look at some more that will save us a lot of time

sum() adds up all the numbers in a list

scores = [80, 95, 70, 88]
print(sum(scores))

Output 333. No need to write a for loop with a total variable, Python does it for us

sorted() returns a new sorted list

numbers = [5, 2, 8, 1, 9, 3]
print(sorted(numbers))
print(numbers)

Output

[1, 2, 3, 5, 8, 9]
[5, 2, 8, 1, 9, 3]

Notice that the original list is unchanged. sorted() gives us a new one. If we want to sort in reverse (descending) order

print(sorted(numbers, reverse=True))

Output [9, 8, 5, 3, 2, 1]

It works on strings too

names = ["Tommy", "Lance", "Cortez", "Phil"]
print(sorted(names))

Output ['Cortez', 'Lance', 'Phil', 'Tommy']. Alphabetical order

enumerate() gives us both the index and the value when looping through a list

Remember the old way?

names = ["Tommy", "Lance", "Cortez"]
for i in range(len(names)):
    print(f"{i}: {names[i]}")

With enumerate() it's much cleaner

names = ["Tommy", "Lance", "Cortez"]
for i, name in enumerate(names):
    print(f"{i}: {name}")

Output

0: Tommy
1: Lance
2: Cortez

Same result, but we don't have to write range(len(...)) and names[i]. Much nicer

zip() combines two lists element by element, like a zipper on a jacket

names = ["Tommy", "Lance", "Cortez"]
scores = [95, 80, 70]

for name, score in zip(names, scores):
    print(f"{name}: {score}")

Output

Tommy: 95
Lance: 80
Cortez: 70

zip() pairs up the first element from each list, then the second, then the third, and so on. If the lists have different lengths, it stops at the shortest one

any() returns True if at least one element is true. all() returns True if every element is true

scores = [80, 95, 40, 70]

has_failure = any(s < 50 for s in scores)
print(has_failure)

all_passed = all(s >= 50 for s in scores)
print(all_passed)

Output

True
False

any(): is there at least one score below 50? Yes (40), so True

all(): are ALL scores at least 50? No (40 is not), so False

abs() gives us the absolute value (removes the minus sign)

print(abs(-5))
print(abs(5))
print(abs(-100))

Output

5
5
100

round() rounds a number

print(round(3.7))
print(round(3.2))
print(round(3.14159, 2))

Output

4
3
3.14

The second argument tells Python how many decimal places we want

Mission: Crew Leaderboard

You have two lists: crew (names) and scores. Using the built-in functions you just learned:

Use zip to print each crew member with their score as name: score
Print Sorted: then the scores sorted from highest to lowest (sorted(..., reverse=True))
Print Total: then the sum of all scores
Print Average: then the average, rounded to 1 decimal place (round(..., 1))
Print All passed: then whether all scores are 50 or more (all(...))
Print Any perfect: then whether any score equals 100 (any(...))

Output

Tommy: 88
Boris: 100
Cara: 47
Dmitri: 73
Sorted: [100, 88, 73, 47]
Total: 308
Average: 77.0
All passed: False
Any perfect: True