python笔记二 基础
10/24对于Python，一切事物都是对象，对象基于类创建，对象所有的功能都是去类里面找的
变量名 = 对象 （值） 重复的功能 创建一个类，然后对象去引用
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整数
age = 18
print(type(age))
<class 'int'>
如果是其他的类型，会在下面显示类地址。
age.__abs__()
all_item = 95
pager = 10
result = all_item.__divmod__(10)
print(result)
(9, 5)
5/65//6
age.__add__(7) age.__rdivmod__(7) abs 绝对值
浮点型float
as_integer_ratio
10/25
字符串
name = 'eric'
print(dir(name))## 这个str所有的成员
['__add__', '__class__', '__contains__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getnewargs__', '__gt__', '__hash__', '__init__', '__iter__', '__le__', '__len__', '__lt__', '__mod__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__rmod__', '__rmul__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'capitalize', 'casefold', 'center', 'count', 'encode', 'endswith', 'expandtabs', 'find', 'format', 'format_map', 'index', 'isalnum', 'isalpha', 'isdecimal', 'isdigit', 'isidentifier', 'islower', 'isnumeric', 'isprintable', 'isspace', 'istitle', 'isupper', 'join', 'ljust', 'lower', 'lstrip', 'maketrans', 'partition', 'replace', 'rfind', 'rindex', 'rjust', 'rpartition', 'rsplit', 'rstrip', 'split', 'splitlines', 'startswith', 'strip', 'swapcase', 'title', 'translate', 'upper', 'zfill']
contains 包含 print(name.__contains__('er')) True
capitalize首字母大写 casefold小写首字母
center 居中
print(name.center(40,'*')) count(self, sub, start=None, end=None)
******************eric******************
count（） 字数
name = '何全'
print(name.encode('gbk'))
b'\xba\xce\xc8\xab'
expantabs #一个type 等于8个空格
name = 'h\tlex'
print(name.expandtabs())
find和 index find找不到返回-1, index找不到报错
name = "he {0} is {1}"
print(name.format('a','b'))
he a is b
join拼接
h = ['h','e','q','u','a','n']
print(''.join(h))
hequan
partition分割
replace('a','b'，1)替换1个
split 指定字符，分割字符 rsplit从右开始
splitlines() 换行符 =split('\n')
swapcase大变小，小写变大写
10/26
list: appendclearcopy countextend 合并indexinsertpop(下标) remove（值） reverse反转sort
元祖tuple
字典dict : keysvaluesitems
for k,v in dic.items()
print(k,v)
10/31
set 无需不重复的元素集合
交集： update_set = old.intersection(new)
差集： delete_set= old.symmetric_difference(update_set)
add_set = new.symmetric_difference(update_set)
s1 = set()
s2 = set()
ret0 = s1.intersection(s2)
ret1 = s1.difference(s2)
ret2 = s1.symmetric_difference(s2)
print(ret0)
print(ret1)
print(ret2)
{22}
{33, 11}
{33, 11, 44}
collections系列
import collections 计数器，多少次重复
obj = collections.Counter('sdafsdafsdafsdafsdaf')
print(obj)
Counter({'f': 5, 'd': 5, 'a': 5, 's': 5})
orderedDict有序字典
dic = collections.OrderedDict()
dic['k1'] = ['v1']
dic['k2'] = ['v2']
print(dic)
OrderedDict([('k1', ['v1']), ('k2', ['v2'])])
defaultDict默认字典
dic = collections.defaultdict(list)
dic['k1'].append('alex')
namedtuple 可命名元祖
mytuple = collections.namedtuple('mytuple',['x','y','z'])
obj = mytuple(11,22,33)
print(obj.x)
11
队列双向队列 单项队列
双进双出 单进单出
deque queue
d = collections.deque()
importqueue
d = queue.Queue()
d.put('123') d.get()
浅拷贝深拷贝 赋值
copy.copy
copy.deepcopy
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