'''
str  int
'''
str
s = ''
print(s.isspace())
# int
'''
list:
'''
lis = [11,22,33,44,55]
# for i in range(len(lis)):
#     print(i)       # i = 0              i = 1               i = 2
#     del lis[i]  # IndexError: list assignment index out of range
#     print(lis)  #  [11,22,33,44,55]   [22, 44, 55]          [22, 44]#第一种
lis = lis[::2]
print(lis)#第二种
l1 = []
for i in lis:if lis.index(i) % 2 == 0:l1.append(i)
lis = l1
print(lis)lis = [11,22,33,44,55]
for i in range(len(lis)-1,-1,-1):if i % 2 == 1:print(i)del lis[i]print(lis)
print(lis)dic = dict.fromkeys([1,2,3],'春哥')
print(dic) # {1: '春哥', 2: '春哥', 3: '春哥'}
dic = dict.fromkeys([1,2,3],[])
print(dic)  # {1: [], 2: [], 3: []}
dic[1].append('袁姐')
print(dic)  # {1: ['袁姐'], 2: ['袁姐'], 3: ['袁姐']}
dic[2].extend('二哥')
print(dic) #{1: ['袁姐', '二', '哥'], 2: ['袁姐', '二', '哥'], 3: ['袁姐', '二', '哥']}
l1 = []
l2 = l1
l3 = l1
l3.append('a')
print(l1,l2,l3)

dic = {'k1':'v1','k2':'v2','a3':'v3'}
dic1 = {}for i in dic:if 'k' not in i:dic1.setdefault(i,dic[i])
dic = dic1
print(dic)l = []
for i in dic:if 'k' in i:l.append(i)
for i in l:del dic[i]
print(dic)# 转化成bool值-为空的为以下
# 0 ''  [] () {} set()#元祖  如果元祖里面只有一个元素且不加,那此元素是什么类型，就是什么类型。
tu1 = (1)
tu2 = (1,)
print(tu1,type(tu1)) # 1 <class 'int'>
print(tu2,type(tu2)) # (1,) <class 'tuple'>
tu1 = ([1])
tu2 = ([1],)
print(tu1,type(tu1)) # [1] <class 'list'>
print(tu2,type(tu2)) # ([1],) <class 'tuple'>
dic = dict.fromkeys([1,2,3,],3)
dic[1] = 4
print(dic)