🫡元素排序
🪄sort(key=None,reverse=False)方法:按特定顺序对列表元素排序
🪄key参数：列表支持的函数，默认为None
🪄reverse参数：控制元素排列方式，默认False表示升序排列
list_4 = [4,5,1,8,0,3,7]
list_4.sort() # 升序排列
print(list_4)
list_4.sort(reverse=True)
print(list_4)
# key支持函数，字符串可以用len.
print(len("Python"))
list_5 = ["Python","java","c++","php"]
list_5.sort(key = len)
print(list_5)
# sorted()不会对原列表产生影响
list_6 = [4,5,1,8,0,3,7]
li = sorted(list_6)
print(list_6)
print(li)
# reverse()方法，逆置列表
list_5.reverse()
print(list_5)
😢删除列表元素（删）
✨1、del语句，用于删除列表中指定位置的元素
list_7 = ["Python","java","c++","php"]
del list_7[1]
print(list_7)
✨2、remove()方法.用于移除某个元素（只移除第一个）
list_8 = ["Python","java","c++","php"]
list_8.remove("java")
print(list_8)
✨3、pop()方法，用于移除列表中某个元素，一般不指定元素，去移除列表最后一个元素
list_9 = ["Python","java","c++","php"]
print(list_9.pop()) # 移除列表中最后一个元素
print(list_9)
print(list_9.pop(1)) # 移除列表中索引为1的元素
print(list_9)
✨4、clear()方法，用于清空列表，注意和del删除列表区分
list_9.clear()
print(list_9)
😅列表推导式
#语法[exp for x in list]
ls = [1,2,3,4,5,6,7,8]
ls = [data*data for data in ls]
print(ls)
😚带if语句：[exp for x in list if cond]
ls = [data for data in ls if data>4]
print(ls)
🤨嵌套for循环：[exp for x list1 for y in list2]
ls_one = [1,2,3]
ls_two = [4,5,6]
ls_three = [x+y for x in ls_one for y in ls_two]
print(ls_three)
