how to detect key presses in pygame code example

Example 1: check key pressed pygame

import pygame
events = pygame.event.get()
for event in events:
    if event.type == pygame.KEYDOWN:
        if event.key == pygame.K_LEFT:
            location -= 1
        if event.key == pygame.K_RIGHT:
            location += 1

Example 2: pygame key pressed once

# Outside loop
pressed = False

# Inside loop
if event.type == pygame.KEYDOWN:
	if event.key == pygame.K_a and not pressed: #K_a can be replaced by any key
		# Do something
		pressed = True
	elif event.key != pygame.K_a:
    	pressed = False