列表 [ ]
bicycles = ['trek','cannondale','redline','specialized']
print(bicycles)
['trek', 'cannondale', 'redline', 'specialized']
访问列表元素
print(bicycles[0])
print(bicycles[0].title())
trek
Trek
索引从 0 而不是 1 开始
print(bicycles[1])
print(bicycles[3])
print(bicycles[-1]) #在不知道列表长度时，索引-1返回倒数第一个列表元素，索引-2返回倒数第二个列表元素，以此类推
cannondale
specialized
specialized
使用列表中的值
message = "My first bicycle was a " + bicycles[0].title() + "."
print(message)
My first bicycle was a Trek.
修改列表元素
motorcycles = ['honda','yamha','suzuki']
print(motorcycles)
motorcycles[0] = 'ducati'
print(motorcycles)
['honda', 'yamha', 'suzuki']
['ducati', 'yamha', 'suzuki']
添加列表元素
motorcycles = []
motorcycles.append('honda') #append方法在列表元素末尾添加
motorcycles.append('yamaha')
motorcycles.append('suzuki')
print(motorcycles)
['honda', 'yamaha', 'suzuki']
motorcycles = ['honda','yamha','suzuki']
motorcycles.insert(0,'ducati') #在列表中插入元素
print(motorcycles)
['ducati', 'honda', 'yamha', 'suzuki']
删除列表元素
motorcycles = ['honda','yamha','suzuki']
print(motorcycles)
del motorcycles[0]
print(motorcycles)
['honda', 'yamha', 'suzuki']
['yamha', 'suzuki']
motorcycles = ['honda','yamha','suzuki']
print(motorcycles)
popped_motorcycles = motorcycles.pop() #pop方法删除列表末尾的值，并且可以使用此值
print(motorcycles)
print(popped_motorcycles)
print("The last motorcycle I owned was a " + popped_motorcycles.title() + ".")
['honda', 'yamha', 'suzuki']
['honda', 'yamha']
suzuki
The last motorcycle I owned was a Suzuki.
motorcycles = ['honda','yamha','suzuki','ducati']
print(motorcycles)
too_expensive = 'ducati'
motorcycles.remove(too_expensive) #remove方法删除列表中已知的值，并且可以使用此值。
#补充：该方法只删除第一个指定的值；若列表中含有重复值，需使用循环来删除
print(motorcycles)
print("\nA " + too_expensive.title() + "is too expensive for me.")
['honda', 'yamha', 'suzuki', 'ducati']
['honda', 'yamha', 'suzuki']
A Ducatiis too expensive for me.
组织列表
永久排序
cars = ['bmw','audi','toyota','subaru']
cars.sort() #sort方法按字母顺序永久排序
print(cars)
['audi', 'bmw', 'subaru', 'toyota']
cars = ['bmw','audi','toyota','subaru']
cars.sort(reverse=True) #sort方法按字母逆序形式永久排序
print(cars)
['toyota', 'subaru', 'bmw', 'audi']
临时排序
cars = ['bmw','audi','toyota','subaru']
print("Here is the original list:")
print(cars)
print("\nHere is the Temporary alphabetical order:")
print(sorted(cars)) #按字母顺序临时性的对列表排序，原列表未改变
print("\nHere is the Temporary alphabetical reversed order:")
print(sorted(cars,reverse=True)) #按字母逆序临时性的对列表排序，原列表未改变
print("\nHere is the original list again:")
print(cars)
Here is the original list:
['bmw', 'audi', 'toyota', 'subaru']
Here is the Temporary alphabetical order:
['audi', 'bmw', 'subaru', 'toyota']
Here is the Temporary alphabetical reversed order:
['toyota', 'subaru', 'bmw', 'audi']
Here is the original list again:
['bmw', 'audi', 'toyota', 'subaru']
倒着打印列表
cars = ['bmw','audi','toyota','subaru']
print(cars)
cars.reverse() #reverse方法对列表永久性的反转，若需要恢复原排序顺序，需再调用一次
print(cars)
cars.reverse()
print(cars)
['bmw', 'audi', 'toyota', 'subaru']
['subaru', 'toyota', 'audi', 'bmw']
['bmw', 'audi', 'toyota', 'subaru']
列表长度
cars = ['bmw','audi','toyota','subaru']
len(cars)
4
操作列表
遍历列表
magicians = ['alice','david','carolina']
for magician in magicians:
print(magician)
alice
david
carolina
遍历时执行更多操作
magicians = ['alice','david','carolina']
for magician in magicians:
print(magician.title() + ", that was a great trick!")
print("I can't wait to see your next trick, " + magician.title() + ".\n")
Alice, that was a great trick!
I can't wait to see your next trick, Alice.
David, that was a great trick!
I can't wait to see your next trick, David.
Carolina, that was a great trick!
I can't wait to see your next trick, Carolina.
遍历结束执行操作
magicians = ['alice','david','carolina']
for magician in magicians:
print(magician.title() + ", that was a great trick!")
print("I can't wait to see your next trick, " + magician.title() + ".\n")
print("Thank you, everyone. That was a great magic show!")
Alice, that was a great trick!
I can't wait to see your next trick, Alice.
David, that was a great trick!
I can't wait to see your next trick, David.
Carolina, that was a great trick!
I can't wait to see your next trick, Carolina.
Thank you, everyone. That was a great magic show!
数值列表
for value in range(1,5): # range函数创建从第一个值开始数，并在到达指定的第二个值后停止，第三个参数是步长
print(value)
1
2
3
4
for value in range(1,6):
print(value)
1
2
3
4
5
创建数值列表
numbers = list(range(1,6))
print(numbers)
[1, 2, 3, 4, 5]
even_numbers = list(range(2,11,2)) #第三个参数2，是步长
print(even_numbers)
[2, 4, 6, 8, 10]
squares = []
for value in range(1,11):
square = value**2
squares.append(square)
print(squares)
[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]
代码简化为：
squares = []
for value in range(1,11):
squares.append(value**2) # **乘方运算
print(squares)
[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]
统计数值列表
digits = [1,2,3,4,5,6,7,8,9,0]
print(min(digits))
print(max(digits))
print(sum(digits))
0
9
45
列表解析
将 for 循环和创建新元素的代码合并成一行，并自动附加新元素
squares = [value**2 for value in range(1,11)]
print(squares)
[1, 4, 9, 16, 25, 36, 49, 64, 81, 100]
切片
索引从你指定的第一个元素开始到你指定倒数第二个数结束
players = ['charles','martina','michael','florence','eli']
print(players[0:3])
print(players[1:4])
print(players[:4]) #从列表开头开始到第4个数结束，注意索引从0开始
print(players[2:]) #从列表第三个数开始到结尾，注意索引从0开始
print(players[-3:]) #从倒数第三个数开始到结束
['charles', 'martina', 'michael']
['martina', 'michael', 'florence']
['charles', 'martina', 'michael', 'florence']
['michael', 'florence', 'eli']
['michael', 'florence', 'eli']
遍历切片
players = ['charles','martina','michael','florence','eli']
print("Here are the first three players on my team:")
for player in players[:3]:
print(player.title())
Here are the first three players on my team:
Charles
Martina
Michael
使用切片复制列表
my_foods = ['pizza','falafel','carrot cake']
friend_foods = my_foods[:]
print(my_foods)
print(friend_foods)
['pizza', 'falafel', 'carrot cake']
['pizza', 'falafel', 'carrot cake']
元组 使用 ( )
Python将不可修改的值称为不可变的，而不可变的列表被称为元组
定义元组
dimensions = (200,50)
print(dimensions[0])
print(dimensions[1])
200
50
修改元组值，提示错误信息
dimensions = (200,50)
dimensions[0] = 250
---------------------------------------------------------------------------
TypeError Traceback (most recent call last)
<ipython-input-13-e6d9c4c4b557> in <module>
1 dimensions = (200,50)
----> 2 dimensions[0] = 250
TypeError: 'tuple' object does not support item assignment
遍历元组值
dimensions = (200,50)
for dimension in dimensions:
print(dimension)
200
50
修改元组变量，对其进行重新复制
dimensions = (200,50)
print("Original dimensions:")
for dimension in dimensions:
print(dimension)
dimensions = (250,40)
print("\nModified dimensions:")
for dimension in dimensions:
print(dimension)
Original dimensions:
200
50
Modified dimensions:
250
40