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1、列表
打印列表
bicycles = ['trek', 'cannondale', 'redline', 'specialized']
print(bicycles)
输出
['trek', 'cannondale', 'redline', 'specialized']
输出列表第一个位置元素
bicycles = ['trek', 'cannondale', 'redline', 'specialized']
print(bicycles[0])
输出
trek
输出列表特定位置元素
bicycles = ['trek', 'cannondale', 'redline', 'specialized']
print(bicycles[1])
print(bicycles[3])
输出
cannondale
specialized
通过将索引指定为-1,可让Python返回最后一个列表元素。类推,-2就是倒数第二个。
bicycles = ['trek', 'cannondale', 'redline', 'specialized']
print(bicycles[-1])
输出
specialized
修改列表元素
motorcycles = ['honda', 'yamaha', 'suzuki']
print(motorcycles)
motorcycles[0] = 'ducati'
print(motorcycles)
输出
['honda', 'yamaha', 'suzuki']
['ducati', 'yamaha', 'suzuki']
列表添加元素
末尾追加
motorcycles = ['honda', 'yamaha', 'suzuki']
print(motorcycles)
motorcycles.append('ducati')
print(motorcycles)
输出
['honda', 'yamaha', 'suzuki']
['honda', 'yamaha', 'suzuki', 'ducati']
列表插入元素
motorcycles = ['honda', 'yamaha', 'suzuki']
motorcycles.insert(0, 'ducati')
print(motorcycles)
输出
['ducati', 'honda', 'yamaha', 'suzuki']
列表删除元素(del)
motorcycles = ['honda', 'yamaha', 'suzuki']
print(motorcycles)
del motorcycles[0]
print(motorcycles)
输出
['honda', 'yamaha', 'suzuki']
['yamaha', 'suzuki']
方法pop()可删除列表末尾的元素,并让你能够接着使用它
motorcycles = ['honda', 'yamaha', 'suzuki']
print(motorcycles)
popped_motorcycle = motorcycles.pop()
print(motorcycles)
print(popped_motorcycle)
输出
['honda', 'yamaha', 'suzuki']
['honda', 'yamaha']
suzuki
也可以使用pop()来删除任何位置的元素,只需在括号中指定要删除的元素的索引
motorcycles = ['honda', 'yamaha', 'suzuki']
first_owned = motorcycles.pop(0)
print('The first motorcycle I owned was a ' + first_owned.title() + '.')
输出
The first motorcycle I owned was a Honda.
根据值删除元素(若好多值相同,remove只能删除第一个指定的值)
motorcycles = ['honda', 'yamaha', 'suzuki', 'ducati']
print(motorcycles)
motorcycles.remove('ducati')
print(motorcycles)
输出
['honda', 'yamaha', 'suzuki', 'ducati']
['honda', 'yamaha', 'suzuki']
列表排序sort()
cars = ['bmw', 'audi', 'toyota', 'subaru']
cars.sort()
print(cars)
输出
['audi', 'bmw', 'subaru', 'toyota']
按与字母顺序相反的顺序排列列表元素
cars = ['bmw', 'audi', 'toyota', 'subaru']
cars.sort(reverse=True)
print(cars)
输出
['toyota', 'subaru', 'bmw', 'audi']
使用函数sorted()对列表进行临时排序
cars = ['bmw', 'audi', 'toyota', 'subaru']
print("Here is the original list:")
print(cars)
print("\nHere is the sorted list:")
print(sorted(cars))
print("\nHere is the original list again:")
print(cars)
输出
Here is the original list:
['bmw', 'audi', 'toyota', 'subaru']
Here is the sorted list:
['audi', 'bmw', 'subaru', 'toyota']
Here is the original list again:
['bmw', 'audi', 'toyota', 'subaru']
调用sorted()后,列表元素的排列顺序没有变。如果要按与字母顺序相反的顺序显示列表,可以向sorted()传递参数reverse=True
倒着打印列表
cars = ['bmw', 'audi', 'toyota', 'subaru']
print(cars)
cars.reverse()
print(cars)
输出
['bmw', 'audi', 'toyota', 'subaru']
['subaru', 'toyota', 'audi', 'bmw']
确定列表的长度
cars = ['bmw', 'audi', 'toyota', 'subaru']
print(len(cars))
输出
4