alien_0 = {‘color‘:‘green‘,‘points‘:5}

print(alien_0[‘color‘])
print(alien_0[‘points‘])

alien_0[‘color‘] = ‘yellow‘
print(alien_0)

del alien_0[‘points‘]
print(alien_0)

user_0 = {
	‘username‘:‘efermi‘,
	‘first‘:‘enrico‘,
	‘last‘:‘fermi‘,
}

for key,value in user_0.items():
	print("\nKey: " + key)
	print("Value: " + value)

for name in user_0.keys():
	print(name.title())

for name in sorted(user_0.keys()):
	print(name.title())	
	
for name in sorted(user_0.values()):
	print(name.title())	

for name in set(user_0.values()):
	print(name.title())	

alien_1 = {‘color‘: ‘green‘, ‘points‘: 5} 
alien_2 = {‘color‘: ‘yellow‘, ‘points‘: 10} 
alien_3 = {‘color‘: ‘red‘, ‘points‘: 15}

aliens = [alien_1,alien_2,alien_3]
for alen in aliens:
	print(alen)

# 创建一个用于存储外星人的空列表
aliens = []

# 创建30个绿色的外星人
for alien_number in range(30):
	new_alien = {‘color‘:‘green‘,‘point‘:5,‘speed‘:‘slow‘}
	aliens.append(new_alien)

# 显示前五个外星人
for alien in aliens[:5]:
	print(alien)
print("...")

# 显示创建了多少个外星人
print("Total number of alents: " + str(len(aliens)))