1.列表推导式：
fruits = ["apple", "banana", "cherry", "kiwi", "mango"]
newlist = []
for x in fruits: #选出含有a的字母
if "a" in x:
newlist.append(x)
print(newlist)
['apple', 'banana', 'mango']
还有一种是执行for循环，再执行if判断
fruits = ["apple", "banana", "cherry", "kiwi", "mango"]
newlist = [x for x in fruits if "a" in x] #意思是选单词，看符不符合里面有没有a
print(newlist)
newlist = [x for x in range(10) if x < 5] #选出比5小的数
print(newlist)
[0, 1, 2, 3, 4]
还有这种，利用离散数学这样理解：
苹果不等于香蕉 1：香蕉不等于香蕉 0：樱桃不等于香蕉 1 ....然后再输出
fruits = ["apple", "banana", "cherry", "kiwi", "mango"]
newlist = [x if x != "banana" else "orange" for x in fruits]
print(newlist)
2.列表排序
区分大小写的排序 sort（）
thislist = ["banana", "Orange", "Kiwi", "cherry"]
thislist.sort()
print(thislist)
["Kiwi", "Orange"，"banana", "cherry"] #
不区分大小写的排序 str.lower
thislist = ["banana","Orange", "Kiwi", "cherry"]
thislist.sort(key = str.lower)
print(thislist)
["banana","cherry"，"Kiwi","Orange"]
倒序 reverse（）
mylist = ["川川一号", "川川二号", "川川三号","川川四号"]
mylist.reverse()
print(mylist)
"川川四号"，"川川三号"，"川川二号"，"川川一号"
3.复制列表
复制列表的副本 copy（）
mylist = ["川川一号", "川川二号", "川川三号","川川四号"]
my = mylist.copy()
print(my)
["川川一号", "川川二号", "川川三号","川川四号"]
制作列表副本：list（）
mylist = ["川川一号", "川川二号", "川川三号","川川四号"]
my = list(mylist)
print(my)
["川川一号", "川川二号", "川川三号","川川四号"]
4.加入列表
最简单是 +
list1 = ["a", "b", "c"]
list2 = [1, 2, 3]
list3 = list1 + list2
print(list3)
['a', 'b', 'c', 1, 2, 3]
list1 = ["a", "b" , "c"]
list2 = [1, 2, 3]for x in list2:
list1.append(x)print(list1)
['a', 'b', 'c', 1, 2, 3]
list1 = ["a", "b" , "c"]
list2 = [1, 2, 3]list1.extend(list2)
print(list1)
['a', 'b', 'c', 1, 2, 3]
