1、删除特例
lis = [11,22,33,44,55] for i in range(len(lis)): print(i) del lis[i] print(lis) #每删除链表中一个值链表就会前移一位
2、删除字典的值
dic = {'k1':'v1','k2':'v2','a3':'v3'}
dic1 = {}
l = []
for i in dic:
if 'k' in i:
l.append(i)
for i in l:
del dic[i]
print(dic)
#输出{'a3': 'v3'}
3、bool值的转换
0 ' ' [] () {} set() 为False
4、如果元祖里面只有一个元素且不加逗号那此元素是什么类型，就是什么类型。
tu1 = (1) tu2 = (1,) print(tu1,type(tu1)) #输出1 <class 'int'> print(tu2,type(tu2)) #输出(1,) <class 'tuple'>
tu1 = ([1]) tu2 = ([1],) print(tu1,type(tu1)) #输出[1] <class 'list'> print(tu2,type(tu2)) #输出([1],) <class 'tuple'>
5、集合：可变的数据类型，他里面的元素必须是不可变的数据类型，无序，不重复。
#增
set1 = {'alex','wusir','ritian','egon','barry',}
set1.add('pzw')
print(set1)
#输出{'pzw', 'barry', 'alex', 'ritian', 'egon', 'wusir'}
不同于第一种
set1 = {'alex','wusir','ritian','egon','barry',}
set1.update('pzw')
print(set1)
#输出{'alex', 'z', 'w', 'ritian', 'barry', 'p', 'wusir', 'egon'}
#删
set1 = {'alex','wusir','ritian','egon','barry',}
set1.pop() # 随机删除
print(set1)
#输出{'ritian', 'wusir', 'alex', 'barry'}
有返回值删除
set1 = {'alex','wusir','ritian','egon','barry',}
print(set1.pop()) # 有返回值
print(set1)
#输出barry
# {'alex', 'wusir', 'egon', 'ritian'}
按元素删除
set1 = {'alex','wusir','ritian','egon','barry',}
set1.remove('alex') # 按元素删除
print(set1)
#输出{'barry', 'egon', 'wusir', 'ritian'}
清空集合
set1 = {'alex','wusir','ritian','egon','barry',}
set1.clear()
print(set1)
#输出set()
#查
set1 = {'alex','wusir','ritian','egon','barry',}
for i in set1:
print(i)
6、集合的交并集
交集
set1 = {1,2,3,4,5}
set2 = {4,5,6,7,8}
set3 = set1 & set2
print(set3)
#输出{4, 5}
print(set1.intersection(set2))
#输出{4, 5}
并集
set1 = {1,2,3,4,5}
set2 = {4,5,6,7,8}
print(set1 | set2)
#输出{1, 2, 3, 4, 5, 6, 7, 8}
print(set2.union(set1))
#输出{1, 2, 3, 4, 5, 6, 7, 8}
反交集
set1 = {1,2,3,4,5}
set2 = {4,5,6,7,8}
print(set1 ^ set2)
#输出{1, 2, 3, 6, 7, 8}
print(set1.symmetric_difference(set2))
#输出{1, 2, 3, 6, 7, 8}
差集
set1 = {1,2,3,4,5}
set2 = {4,5,6,7,8}
print(set1 - set2)
#输出{1, 2, 3}
print(set1.difference(set2))
#输出{1, 2, 3}
子集与超集
set1 = {1,2,3,}
set2 = {1,2,3,4,5,6}
print(set1 < set2)
print(set1.issubset(set2)) # 这两个相同，都是说明set1是set2子集。
print(set2 > set1)
print(set2.issuperset(set1)) # 这两个相同，都是说明set2是set1超集。
7、去重
li = [1,2,33,33,2,1,4,5,6,6] set1 = set(li) print(set1) #输出{1, 2, 33, 4, 5, 6} li = list(set1) print(li) #输出[1, 2, 33, 4, 5, 6]
特例
s = frozenset('barry') print(s,type(s)) #输出frozenset({'r', 'b', 'y', 'a'}) <class 'frozenset'>
8、赋值运算
l1 = [1,2,3] l2 = l1 l1.append('a') print(l1,l2) #输出[1, 2, 3, 'a'] [1, 2, 3, 'a']
#copy
l1 = [1,2,3] l2 = l1.copy() print(l1,l2) #输出[1, 2, 3] [1, 2, 3]
l1 = [1,[1],2,3,4] l2 = l1[:] l1[1].append('a') print(l1,l2) #输出[1, [1, 'a'], 2, 3, 4] [1, [1, 'a'], 2, 3, 4]
li = ['alex','taibai','wusir','egon'] for i in li: print(li.index(i),i) #输出 0 alex # 1 taibai # 2 wusir # 3 egon