The key difference is that elif will only be executed if the previous conditions are not met (False). Whereas if will continue to evaluate even if the previous condition is met (True).

# if -> if
a = 2
if a > 1:
    a += 1
if a > 2:
    a +=1

a # 4 

# if -> elif 
a = 2
if a > 1:
    a += 1
elif a > 2:
    a +=1
a # 3

In the first example, a returns 4 because both if are evaluated to be true so they were executed. Whereas the second example, the a returns 3 because elif will only execute if the previous condition is false.

The for loop is used to iterate over a sequence (such as a list, a tuple, or a set) and execute a block of code for each item in the sequence.

Use case: for loops are often used when you know the number of iterations beforehand, such as iterating over elements in a sequence.

for <var> in <iterable>:
    <statement(s)>

1. var: variable that takes the value of each item inside the sequence on each iteration.
2. iterable: collection of objects in a sequence (inbuilt function-range/random or list).
3. statement(s): actions to be evaluated/performed for each value at the end of each iteration.

The while loop is used to repeatedly execute a block of code as long as a specified condition is true.

Use case: while loops are used when the number of iterations is not known and is determined by a condition.

while <condition>:
    <statement(s)>

1. condition: The condition to evaluate whether to stay within the loop. If the condition is evaluated to be False, the loop will stop.
2. statement(s): actions to be evaluated/performed for each value at the end of each iteration.