python编程从入门到实践--第4章 操作列表

一。遍历整个列表

　　注意缩进，与不要遗漏冒号。

magicians = ['alice', 'david', 'carolina']
for magician in magicians:
    #print(magician)
    print(f"{magician.title()}, that waw a great trick!")
    print(f"I can't wait to see your next trick, {magician.title()}.\n")

print("Thank you, everyone. That waw a great magic show!")
print("This is test indentationError: unexpected indent")

二。创建数值列表

# 创建数值列表--实际最大输出4
for value in range(1, 5):
    print(value)

# 创建数字列表--实际最大输出5
numbers = list(range(1, 6))
print(numbers)

# 创建偶数
even_numbers = list(range(2, 11, 2))
print(even_numbers)

# 创建平方值--1~10的平方值
squares = []
for value in range(1, 11):
     squares.append(value**2)

print(squares)

# 统计计算
digits = [1, 2, 3, 4, 5, 6, 7, 8, 9, 0]
print(min(digits))
print(max(digits))
print(sum(digits))

#列表解析
squares1 = [value**2 for value in range(1, 11)]
print(squares1)

三。使用列表的一部分

　　切片与遍历切片

players = ['charles', 'martina', 'michael', 'florence', 'eli']
print(players[0:3])     # 起始0,终止3前元素--['charles', 'martina', 'michael'] 
print(players[1:4])     # 起始1,终止4前元素--['martina', 'michael', 'florence']
print(players[:4])      # 起始0,终止4前元素--['charles', 'martina', 'michael', 'florence']
print(players[2:])      # 起始2到最末尾元素--['michael', 'florence', 'eli']
print(players[-3:])     # 起始倒数第三个至最末尾一个元素--['michael', 'florence', 'eli']

# 遍历切片
print("Here are the first three plyers on my team:")
for player in players[:3]:
    print(player.title())

四。复制列表

　　深拷贝与浅拷贝

my_foods = ['pizza', 'falafel', 'carrot cake']

#friend_foods = my_foods[:]      # 深拷贝--两个不同列表
friend_foods = my_foods          # 浅拷贝--相同一个列表,同一个引用


print("My favorite foods are:")
print(my_foods)

print("\nMy friend's favorite foods are:")
print(friend_foods)

my_foods.append('cannoli')
friend_foods.append('ice cream')

print("My favorite foods are:")
print(my_foods)

print("\nMy friends favoirte foods are:")
print(friend_foods)

五。元组

相当于不可变数组，只在构造时可以修改值，后的不能修改。

dimensions = (200, 50)  # 只有二个元素
print(dimensions[0])
print(dimensions[1])

my_t = (3,)     # 单个元素,也要加逗号
print(my_t[0])

#dimensions[0] = 300    # 运时报错,'tuple' object does not support item assignment

# 遍历元组中所有元素
for dimension in dimensions:
    print(dimension)


# 修改元组变量--构造时
dimensions = (400, 100, 50)
print("\nModified dimensions:")
for dimension in dimensions:
    print(dimension)