PY基础之列表的内置方法

PY基础之列表的内置方法

1. 作用

描述多个值,比如爱好

2. 定义方式

hobby_list = ['play', 'swimmindeg', 'dancing', '666']
lt = list('nick')

3. 内置方法

hobby = ['play', 'swimming', 'dancing', '666']
hobby[1] = 'rap'
print(hobby) # ['play', 'rap', 'dancing', '666']

print(hobby[::-1]) # ['666', 'dancing', 'rap', 'play']

print(len(hobby)) # 4

print('play' in hobby) # True

for i in hobby:
    print(i)
'''
play
rap
dancing
666
'''

del hobby[-1]
print(hobby)  # ['play', 'rap', 'dancing']

hobby.append('666')
print(hobby)  # ['play', 'rap', 'dancing', '666', '666']
print(hobby.count('666'))  # 2

hobby.extend([1,2,3,4])
print(hobby) # ['play', 'rap', 'dancing', '666', '666', 1, 2, 3, 4]

# hobby.clear() # 清除

lt = hobby.copy()  # 复制
print(lt)

hobby[-1] = 233
print(hobby) # ['play', 'rap', 'dancing', '666', '666', 1, 2, 3, 233]
print(lt) # ['play', 'rap', 'dancing', '666', '666', 1, 2, 3, 4]

print(hobby.pop()) # 默认删除最后一个元素，并返回该元素

print(hobby.index('play'))

hobby.insert(0,'1')  # 在指定位序插入字符
print(hobby)

hobby.remove('1')  # 移除指定元素，找不到会报错
print(hobby)

hobby.reverse() # 反转
print(hobby)

hobby1 = [1,2,4,1,3,99,65]  # 排序
hobby1.sort()
print(hobby1) # [1, 1, 2, 3, 4, 65, 99]

# 实例，按数字排序
hobby_list = [['nick', 1000], ['jason', 500000], ['sean', 2000], ['tank', 10000]]

def func(i):
    return i[1]
hobby_list.sort(key=func)
hobby_list.reverse()
print(hobby_list)  # [['jason', 500000], ['tank', 10000], ['sean', 2000], ['nick', 1000]]

4. 存一个值还是多个值

多个值

5. 有序or无序

有序

6. 可变or不可变(重点)

可变