Peek and is_empty

Peek the top without removing and check emptiness.

Peek and is empty

peek() shows the top element of the stack without removing it. is_empty() tells whether the stack is empty.

These two operations are important for safe stack use. is_empty before pop, peek before reading an element.

Stack is used in undo operations, function call stack, parenthesis matching and DFS.

For example, undo in a text editor pushes each write to a stack and undo pops from it.

Write stack_peek(stack). Return the top element without removing. Print 3 with print(stack_peek([1, 2, 3])).

Show example solution

def stack_peek(stack):
    # Peek
    return stack[-1]
print(stack_peek([1, 2, 3]))

Peek

Read the top element without removing with ____.

Show answer

Read the top element without removing with peek.