字符串 和 字典

Posted 2022-03-10 wwz-wwz

>>> f="hi,%a is a %a" #%后面只能跟同一个值
>>> v=(‘mac‘,‘dog‘)
>>> f % v #最原始
"hi,‘mac‘ is a ‘dog‘"

>>> from string import Template
>>> tmp=Template(‘hi, $who is a $what‘)#引用模块
>>> tmp.substitute(who=‘mac‘,what=‘dog‘)
‘hi, mac is a dog‘

>>> "hi, is a ".format(‘mac‘,‘dog‘)#使用默认顺序
‘hi,mac is a dog‘
>>> "hi,1 is a 0".format(‘mac‘,‘dog‘)#索引
‘hi,dog is a mac‘
>>> "hi,name is a what".format(name=‘mac‘,what=‘dog‘)#制定名称
‘hi,mac is a dog‘

>>> names=[‘aaa‘,‘bbbb‘]
>>> ‘hi,name[0] is a dog‘.format(name=names)#可传序列
‘hi,aaa is a dog‘

>>> ‘num:f‘.format(num=100)#指定转换格式（值：格式）
‘100.000000‘

>>> ‘name‘.center(6) #指定（6）长度，使nameu居中
‘ name ‘


>>> ‘name‘.find(‘am‘)#返回第一个的索引，没有返回-1
1
>>> ‘name‘.find(‘aaaa‘)
-1
>>> ‘hi,name is a dog‘.find(‘is‘,2,100)#find(‘搜索值‘，开始索引，结束索引)
8

>>> ‘+‘.join([‘1‘,‘2‘,‘3‘])# join
‘1+2+3‘


>>> ‘AAA‘.lower()#小写
‘aaa‘

>>> ‘name‘.replace(‘am‘,‘aaaaa‘)#替换
‘naaaaae‘

>>> "nanenanenrnr".split(‘n‘)#分解
[‘‘, ‘a‘, ‘e‘, ‘a‘, ‘e‘, ‘r‘, ‘r‘]

>>> ‘ name ‘.strip()#去除前后空格
‘name‘
>>> ‘ ! **na!m*e !! ***‘.strip(‘*!‘)#去除指定字符
‘ ! **na!m*e !! ‘

>>> dic=‘a‘:1,‘b‘:2,‘c‘:3#创建字典 1
>>> dic[‘c‘]
3
>>> items=[(‘name‘,‘张三‘),(‘age‘,42)]#创建字典 2
>>> d=dict(items)
>>> d
‘name‘: ‘张三‘, ‘age‘: 42
>>> d=dict(name=‘张三‘,age=31)#创建字典 3
>>> d
‘name‘: ‘张三‘, ‘age‘: 31

>>> book=‘a‘:12,‘b‘:111,‘c‘:333
>>> book
‘a‘: 12, ‘b‘: 111, ‘c‘: 333
>>> ‘a is a‘.format(a=‘fdssf‘)
‘a is fdssf‘
>>> ‘a is a‘.format_map(book)#字符转格式format_map
‘a is 12‘

>>> dict.fromkeys(‘name‘,‘age‘) #创建字典fromkeys
‘n‘: ‘age‘, ‘a‘: ‘age‘, ‘m‘: ‘age‘, ‘e‘: ‘age‘
>>> dict.fromkeys([‘name‘,‘age‘])
‘name‘: None, ‘age‘: None
>>> dict.fromkeys([‘name‘,‘age‘],‘unknow‘)#设置默认值
‘name‘: ‘unknow‘, ‘age‘: ‘unknow‘
>>>

‘a‘: 1, ‘b‘: 2, ‘c‘: 3
>>> dic.get(‘b‘) #get获取值，不报错，没有的话返回None。第二个参数可设置默认值
2


>>> dic
‘a‘: 1, ‘b‘: 2, ‘c‘: 3
>>> dic.pop() #必须有key参数
Traceback (most recent call last):
File "<pyshell#75>", line 1, in <module>
dic.pop()
TypeError: pop expected at least 1 arguments, got 0
>>> dic.popitem() #随机弹出并删除
(‘c‘, 3)
>>> dic
‘a‘: 1, ‘b‘: 2


>>> dic
‘a‘: 1, ‘b‘: 2
>>> dic.setdefault(‘c‘,1111)#获取key为c的值，如果没有的c，就添加k=1 v=1111的元素，1111为可选参数，不填默认为None
1111
>>> dic
‘a‘: 1, ‘b‘: 2, ‘c‘: 1111
>>> dic.setdefault(‘c‘,222)#如果已经有k为c的值了，222将无意义。
1111
>>> dic
‘a‘: 1, ‘b‘: 2, ‘c‘: 1111
>>>

 

>>> dic
‘a‘: 1, ‘b‘: 2, ‘c‘: 1111
>>> dd=dict.fromkeys([‘dd‘,‘ee‘],2222)
>>> dd
‘dd‘: 2222, ‘ee‘: 2222
>>> dd[‘a‘]=1111
>>> dd
‘dd‘: 2222, ‘ee‘: 2222, ‘a‘: 1111
>>> dic.update(dd)#对于通过参数提供的字典，将其项添加到当前字典中。如果当前字典包含键相同的项，就替换它。 
>>> dic
‘a‘: 1111, ‘b‘: 2, ‘c‘: 1111, ‘dd‘: 2222, ‘ee‘: 2222
>>>