project: Assessment: For loops

Tags technical-assessment skill/for_loops

Many people do pattern matching instead of understanding. Here are some common things that will be tested:

Note about submission format

On Tilde you’ll notice that this card is asking for a link submission. Please don’t worry about submitting a link. You will be assessed according to TOPIC: Introduction to live assessments

JS and Java learners understand that they can count up and down

for (some_initialiser,some_check,some_update){
    ...
}

They should be able to reason about each of the different parts of the configuration of the loops.

Python learners understand range and in

for x in [1,2,3,4,5]:
   ...

for x in range(len(arr))
    ...
  • They should be able to move forward or backwards.
  • They should also understand how to use enumerate.

All learners understand that the whole body of the loop executes on each iteration

for i in range(5):
    print('a')
    print('b')

All learners understand that loop counters don’t magically fetch information from other data structures

arr = ['a','b','c']

for (let i = 0; i< arr.length; i++){
    console.log(i)    // this does not print a, b or c ever
}

All learners should be able to reason about nested for loops

for n in [0,1,2]:
    for m in [0,1,2]:
        print(n,m)   # this executes 9 times. Why? What gets printed?
    print("here")    # this one only executes 3 times. Why?

All learners should be able to reason about continue and break in a single for loop

E.g.:

for (let i = 0; i < 5; i++){
    print(i)
    print("a")
    if (i <2) continue; // what does this do?
    print("b")
    if (i>4) break;     // how about this?
    print("c")
}

All learners should be able to reason about continue and break within a nested for loop

for (let n=0; n<3; n++){
    print(n)
    for (let i = 0; i < 5; i++){
        print(i)
        print("a")
        if (i <2) continue; // what does this do?
        print("b")
        if (i>4) break;     // how about this?
        print("c")
    }
}

All learners should be able to iterate over strings and arrays

Some people think you need to turn strings into arrays before you can start iterating over them. This is not the case!

All learners should understand the basics of while loops

  • Can you convert a for loop into a while loop?
  • How do break and continue statements work in while loops versus for loops?
RAW CONTENT URL