python基础-基本数据类型

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‘’’
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]

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)

dic = dict.fromkeys([1,2,3],[])

print(dic) # {1: [], 2: [], 3: []}

dic[1].append(‘袁姐’)

print(dic)

dic[2].extend(‘二哥’)

print(dic)

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

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))

print(tu2,type(tu2))

tu1 = ([1])

tu2 = ([1],)

print(tu1,type(tu1))

print(tu2,type(tu2))

dic = dict.fromkeys([1,2,3,],3)

dic[1] = 4

print(dic)