Loops

In Python, there are several loop constructs commonly used for solving array problems. Here are the most common ones:

For Loop: The for loop is widely used for iterating over elements in an array or any iterable object.

It allows you to execute a block of code for each element in the array.
```
arr = [1, 2, 3, 4, 5]
for num in array: 
  print(num)
```
While Loop:

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

It's often used when you don't know in advance how many iterations are needed.
```
i = 0 
while i < len(array): 
  print(array[i]) 
  i += 1
```
Nested Loops: Nested loops involve placing one loop inside another loop. They are used when you need to iterate over elements of a multi-dimensional array or perform operations that require multiple levels of iteration. For example:
```
matrix = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]
for row in matrix:
    for num in row:
        print(num)
```
Enumerate: The enumerate() function is used to iterate over both the elements and their indices in an array. It returns tuples containing the index and the corresponding element. For example:
```
for i, num in enumerate(arr): 
  print(f"Element at index {i} is {num}")
```