字典的创建8种方法

#1. 创建空字典
dic = {}
print(dic)            #{}
print(type(dic))       # <class 'dict'>


# 2.通过赋值创建。
dic={'sop':1,'egg':2,'bar':5}
print(dic)     # {'sop':1,'egg': 2, 'bar': 5}

# 3.通过dict函数和关键字创建
dic=dict(spam=1,egg=2,bar=3)
print(dic)   #{'spam': 1, 'egg': 2, 'bar': 3}


#练习
# dic={}
# print(dic)
#
# cv={'ghd':151,'sdfg':54,'gsdf':56}
# print(cv)
#
# cb=dict(fgsd=12,sgs=25,gsdf=2165)
#print(cb)

#4.通过列表转字典 用dict函数
er=[('ggsg','gs'),('ghd',165)]
print(dict(er))     #{'ggsg': 'gs', 'ghd': 165}


#5.zip函数
re=zip([1,23,45,65,4])     #zip 后 可为迭代对象
print(re)     #<zip object at 0x00894648>    迭代对象
for i in re:
    print(i)
# (1,)
# (23,)
# (45,)
# (65,)
# (4,)

tu= dict(zip(['one', 'two', 'three'],[1, 2, 3]))
print(tu)    #{'one': 1, 'two': 2, 'three': 3}

#6.字典的推导式创建
xm={str(i):i*2 for i in range(9)}
print(xm)    #{'0': 0, '1': 2, '2': 4, '3': 6, '4': 8, '5': 10, '6': 12, '7': 14, '8': 16}

lg = { k: i for k,i in [('one', 1),('two', 2),('three', 3)]}
print(lg)   #{'one': 1, 'two': 2, 'three': 3}



#7.通过dict.fromkeys()
# 通常用来初始化字典.设置valoe的默认值
xn=dict.fromkeys('nihao',3)
print(xn)   #{'n': 3, 'i': 3, 'h': 3, 'a': 3, 'o': 3}

#8.其他方式
l = ['d',5,'f',5,'g',6,'h',5]
de=dict(zip(l[::2],l[1::2]))
print(de)    #{'d': 5, 'f': 5, 'g': 6, 'h': 5}

l = ['d',5,'f',5,'g',6,'h',5]
re=len(l)
i=0
while i >len(l):
 print(i)
 i+=1