字典
>>> dict1={'1':'a','2':'b','3':'c','4':'d'}
>>> print(dict1['a'])
Traceback (most recent call last):
File "<pyshell#2>", line 1, in <module>
print(dict1['a'])
KeyError: 'a'
>>> print(dict1['1'])
a什么类型作为键值对都可以
>>> dict2={1:'a',2:'b',3:'c'}
>>> dict2[1]
'a'
>>> dict3={}
>>> dict3
{}
>>> help(dict)这货是一个工厂函数
Help on class dict in module builtins:
class dict(object)
| dict() -> new empty dictionary
| dict(mapping) -> new dictionary initialized from a mapping object's
| (key, value) pairs
| dict(iterable) -> new dictionary initialized as if via:
| d = {}
| for k, v in iterable:
| d[k] = v
| dict(**kwargs) -> new dictionary initialized with the name=value pairs
| in the keyword argument list. For example: dict(one=1, two=2)
|
| Methods defined here:
|
| __contains__(self, key, /)
| True if D has a key k, else False.
|
| __delitem__(self, key, /)
| Delete self[key].
|
| __eq__(self, value, /)
| Return self==value.
|
| __ge__(self, value, /)
| Return self>=value.
|
| __getattribute__(self, name, /)
| Return getattr(self, name).
|
| __getitem__(...)
| x.__getitem__(y) <==> x[y]
|
| __gt__(self, value, /)
| Return self>value.
|
| __init__(self, /, *args, **kwargs)
| Initialize self. See help(type(self)) for accurate signature.
|
| __iter__(self, /)
| Implement iter(self).
|
| __le__(self, value, /)
| Return self<=value.
|
| __len__(self, /)
| Return len(self).
|
| __lt__(self, value, /)
| Return self<value.
|
| __ne__(self, value, /)
| Return self!=value.
|
| __new__(*args, **kwargs) from builtins.type
| Create and return a new object. See help(type) for accurate signature.
|
| __repr__(self, /)
| Return repr(self).
|
| __setitem__(self, key, value, /)
| Set self[key] to value.
|
| __sizeof__(...)
| D.__sizeof__() -> size of D in memory, in bytes
|
| clear(...)
| D.clear() -> None. Remove all items from D.
|
| copy(...)
| D.copy() -> a shallow copy of D
|
| fromkeys(iterable, value=None, /) from builtins.type
| Returns a new dict with keys from iterable and values equal to value.
|
| get(...)
| D.get(k[,d]) -> D[k] if k in D, else d. d defaults to None.
|
| items(...)
| D.items() -> a set-like object providing a view on D's items
|
| keys(...)
| D.keys() -> a set-like object providing a view on D's keys
|
| pop(...)
| D.pop(k[,d]) -> v, remove specified key and return the corresponding value.
| If key is not found, d is returned if given, otherwise KeyError is raised
|
| popitem(...)
| D.popitem() -> (k, v), remove and return some (key, value) pair as a
| 2-tuple; but raise KeyError if D is empty.
|
| setdefault(...)
| D.setdefault(k[,d]) -> D.get(k,d), also set D[k]=d if k not in D
|
| update(...)
| D.update([E, ]**F) -> None. Update D from dict/iterable E and F.
| If E is present and has a .keys() method, then does: for k in E: D[k] = E[k]
| If E is present and lacks a .keys() method, then does: for k, v in E: D[k] = v
| In either case, this is followed by: for k in F: D[k] = F[k]
|
| values(...)
| D.values() -> an object providing a view on D's values
|
| ----------------------------------------------------------------------
| Data and other attributes defined here:
|
| __hash__ = None
>>> dict3=dict((('f',70),('i',105),('s',115),('h',104)))
>>> dict3
{'i': 105, 'h': 104, 'f': 70, 's': 115}
>>> dict4=dict(1='d',2='c')
SyntaxError: keyword can't be an expression
>>> dict4=dict(zyj='aaa',21='age')
SyntaxError: keyword can't be an expression
>>> dict4=dict(zyj='a',miss='b')
>>> dict44
Traceback (most recent call last):
File "<pyshell#14>", line 1, in <module>
dict44
NameError: name 'dict44' is not defined
>>> dict4
{'zyj': 'a', 'miss': 'b'}
>>> dict4['aa']='sss'
>>> dict4
{'zyj': 'a', 'aa': 'sss', 'miss': 'b'}
>>> dict5=dict('ww'='ff','wr'='rew')
SyntaxError: keyword can't be an expression>>>
字典常用函数
formkeys()
>>> dict1={}
>>> dict1.formkeys((1,2,3))
Traceback (most recent call last):
File "<pyshell#20>", line 1, in <module>
dict1.formkeys((1,2,3))
AttributeError: 'dict' object has no attribute 'formkeys'
>>> dict1.fromkeys((1,2,3))
{1: None, 2: None, 3: None}
>>> dict1.fromkeys((1,2,3),('one','two','three'))
{1: ('one', 'two', 'three'), 2: ('one', 'two', 'three'), 3: ('one', 'two', 'three')}
>>> dict1=dict1.fromkeys((range(32)),'zan')
>>> dict1
{0: 'zan', 1: 'zan', 2: 'zan', 3: 'zan', 4: 'zan', 5: 'zan', 6: 'zan', 7: 'zan', 8: 'zan', 9: 'zan', 10: 'zan', 11: 'zan', 12: 'zan', 13: 'zan', 14: 'zan', 15: 'zan', 16: 'zan', 17: 'zan', 18: 'zan', 19: 'zan', 20: 'zan', 21: 'zan', 22: 'zan', 23: 'zan', 24: 'zan', 25: 'zan', 26: 'zan', 27: 'zan', 28: 'zan', 29: 'zan', 30: 'zan', 31: 'zan'}
>>> for eachKey in dict1.keys():
print(eachKey)
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
>>> for eachKey in dict1.values():
print(eachKey)
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
zan
>>> for eachKey in dict1.items():
print(eachKey)
(0, 'zan')
(1, 'zan')
(2, 'zan')
(3, 'zan')
(4, 'zan')
(5, 'zan')
(6, 'zan')
(7, 'zan')
(8, 'zan')
(9, 'zan')
(10, 'zan')
(11, 'zan')
(12, 'zan')
(13, 'zan')
(14, 'zan')
(15, 'zan')
(16, 'zan')
(17, 'zan')
(18, 'zan')
(19, 'zan')
(20, 'zan')
(21, 'zan')
(22, 'zan')
(23, 'zan')
(24, 'zan')
(25, 'zan')
(26, 'zan')
(27, 'zan')
(28, 'zan')
(29, 'zan')
(30, 'zan')
(31, 'zan')
>>> print(dict1[43])
Traceback (most recent call last):
File "<pyshell#32>", line 1, in <module>
print(dict1[43])
KeyError: 43
>>> 不想报错怎么办？
>>> print(dict1.get(32))
None
>>> 31 in dict1
True
>>> 32 in dict1
False
>>>
清空
>>> dict1.clear()
>>> dict1
{}
>>> a={'name':'zyj'}
>>> b=a
>>> a={}
>>> a
{}
>>> b
{'name': 'zyj'}
>>>
>>> a.clear()
>>> a
{}
>>> b
{'name': 'zyj'}>>>
Copy函数（是浅拷贝）
>>> a={1:'a',2:'b'}
>>> b=a.copy()
>>> c=a
>>> c
{1: 'a', 2: 'b'}
>>> a
{1: 'a', 2: 'b'}
>>> b
{1: 'a', 2: 'b'}
>>> id(a)
150322846600
>>> id(b)
150323498376
>>> id(c)
150322846600
>>> a={}
>>> b
{1: 'a', 2: 'b'}
>>> c
{1: 'a', 2: 'b'}
>>> c[3]='three'
>>> c
{1: 'a', 2: 'b', 3: 'three'}
>>> b
{1: 'a', 2: 'b'}
>>> a
{}
>>> b.pop(3)
Traceback (most recent call last):
File "<pyshell#62>", line 1, in <module>
b.pop(3)
KeyError: 3
>>> b.pop(2)
'b'
>>> b.popitem(2)
Traceback (most recent call last):
File "<pyshell#64>", line 1, in <module>
b.popitem(2)
TypeError: popitem() takes no arguments (1 given)
>>> b.popitem()
(1, 'a')
>>> b.setdefault(5,'five')
'five'
>>> a
{}
update
>>> c
{1: 'a', 2: 'b', 3: 'three'}
>>> d={2:'dddd'}
>>> d
{2: 'dddd'}
>>> a.update(d)
>>> a
{2: 'dddd'}
>>> c.update(d)
>>> c
{1: 'a', 2: 'dddd', 3: 'three'}集合
如何创建：
{}
set()工厂函数
>>> num={}
>>> typr(num)
Traceback (most recent call last):
File "<pyshell#1>", line 1, in <module>
typr(num)
NameError: name 'typr' is not defined
>>> type(num)
<class 'dict'>
>>> num={1,2,3,4}
>>> type(num)
<class 'set'>
>>> num[2]
Traceback (most recent call last):
File "<pyshell#5>", line 1, in <module>
num[2]
TypeError: 'set' object does not support indexing
>>> set1=set([1,2,3,4])
>>> set1
{1, 2, 3, 4}>>>
列表去重
>>> num1=[1,2,3,3,2,5,1,5]
>>> num1=list（set(num1))
SyntaxError: invalid character in identifier 中文字符的问题
>>> num1=list(set(num1))
>>> num1
[1, 2, 3, 5]自动排了序
>>> num1=[1,2,3,3,2,5,1,5]
>>> num1=list（set(num1))
SyntaxError: invalid character in identifier
>>> num1=list(set(num1))
>>> num1
[1, 2, 3, 5]不可变集合frozen
>>> num3=frozenset([1,2,3,4,5])
>>> num3.add(0)
Traceback (most recent call last):
File "<pyshell#31>", line 1, in <module>
num3.add(0)
AttributeError: 'frozenset' object has no attribute 'add'文件操作
open
‘r’只读
‘w’覆盖写
‘x’如果文件已经存在，打开将引发异常
‘a’写入追加
‘b’二进制打开
‘t’以文本模式打开
‘+’可读写（可添加到其他模式中使用）
‘U’通用换行符支持
>>> f=open('F:\\python\\hano.py')
>>> f
<_io.TextIOWrapper name='F:\\python\\hano.py' mode='r' encoding='cp936'>
f.close() python忘记关闭不会造成内存泄露，但是写入数据之后最好关闭，否则还在缓存中
f.read(size=-1)读取多少个字符
>>> f.read()
'def hano(n,x,y,z):\n if(n==1):\n print(x,"-->",z)\n return\n hano(n-1,x,z,y)\n print(x,"-->",z)\n hano(n-1,y,x,z)\nn=int(input())\nhano(n,\'x\',\'y\',\'z\')\n \n'
>>> f.read()
''文件指针指到了文件末尾
f.readline()写入模式打开，如果文件存在，则在末尾追加写入
f.write(str)将字符串写入文件
f.writelines(seq)向文件写入字符串序列seq，返回字符串的可迭代对象
f.seek(offset,from)在文件中移动文件指针，从from（0起始，1当前，2末尾）偏移offset字节
f.tell()返回当前位置
>>> f=open('F:\\python\\hano.py')
>>> f.read(5)
'def h'
>>> f.seek(45,0)
45
>>> f.readline()
'int(x,"-->",z)\n'
>>> f.seek(0,0)
0
>>> for each_line in f:
print(each_line)
def hano(n,x,y,z):
if(n==1):
print(x,"-->",z)
return
hano(n-1,x,z,y)
print(x,"-->",z)
hano(n-1,y,x,z)
n=int(input())
hano(n,'x','y','z')
>>> f.write('i love misszhou')
Traceback (most recent call last):
File "<pyshell#15>", line 1, in <module>
f.write('i love misszhou')
io.UnsupportedOperation: not writable
>>> f=open('F:\\python\\cout.txt','w')
>>> f.write('misszhou 要努力')
12
>>> f.close()
文件系统
OS模块：
不需要关心具体的操作系统（python是跨平台的）
>>> import os
>>> os.getced()
Traceback (most recent call last):
File "<pyshell#6>", line 1, in <module>
os.getced()
AttributeError: module 'os' has no attribute 'getced'
>>> os.cwd()
Traceback (most recent call last):
File "<pyshell#7>", line 1, in <module>
os.cwd()
AttributeError: module 'os' has no attribute 'cwd'
>>> os.getcwd()
'C:\\Program Files\\Python35'
>>> os.chdir('E:\\')
>>> os.getcwd()
'E:\\'
>>> os.listdir('E:\\')
['$RECYCLE.BIN', '360Downloads', 'BaiduYunDownload', 'KwDownload', 'MyDownloads', 'System Volume Information', '[LAMP兄弟连新版原创PHP视频教程].16课软件_LAMP环境安装(PHP环境搭建).rar', '[LAMP兄弟连新版原创PHP视频教程].17_在Windows系统中分别安装PHP工作环境.rar', '[LAMP兄弟连新版原创PHP视频教程].18_在Windows系统中安装集成的PHP开发环境', '[LAMP兄弟连新版原创PHP视频教程].18_在Windows系统中安装集成的PHP开发环境.rar', '[LAMP兄弟连新版原创PHP视频教程].19_Apache服务器的基本配置', '[LAMP兄弟连新版原创PHP视频教程].19_Apache服务器的基本配置.rar', '迅雷下载']
>>> os.mkdir('E:\\a')
>>> os.makedirs('E:\\a\\b\\c')
>>> os.remove('E:\\a\\b\\tmp.txt')
>>> os.remove('E:\\a')
Traceback (most recent call last):
File "<pyshell#15>", line 1, in <module>
os.remove('E:\\a')
PermissionError: [WinError 5] 拒绝访问。: 'E:\\a'
>>> os.removedirs('E:\\a')
Traceback (most recent call last):
File "<pyshell#16>", line 1, in <module>
os.removedirs('E:\\a')
File "C:\Program Files\Python35\lib\os.py", line 259, in removedirs
rmdir(name)
OSError: [WinError 145] 目录不是空的。: 'E:\\a'
>>> os.system('calc')
0
>>> os.curdir
'.'os.curdir (‘.’)
os.pardir (‘..’)
os.seq 输出操作系统特定的路径分割符 win \\ linux /
os.linesep win ‘\r\n’ linux ‘\n’
os.name 指代当前使用的操作系统 posix-linux nt-win mac os2 ce java
os.path模块
getatime()访问时间
getctime()创建时间
getmtime()修改时间————
格林尼治时间gmtime
当地时间localtime
>>> os.name
'nt'
>>> os.path.basename('E:\\A\\misszhou')
'misszhou'
>>> os.path.dirname('E:\\A\\misszhou.txt')
'E:\\A'
>>> os.path.join('A','b')
'A\\b'
>>> os.path.join('E:','a')
'E:a'
>>> os.path.join('A','B','C')
'A\\B\\C'
>>> os.path.join('A','B')
'A\\B'
>>> os.path.split('E:\\A\\B\\C')
('E:\\A\\B', 'C')
>>> os.path.splitext('E:\\a\\b')
('E:\\a\\b', '')
>>> import time
>>> time.gmtime(os.path.getatime('E:\\a
SyntaxError: EOL while scanning string literal
>>> time.gmtime(os.path.getatime('E:\\a'))
time.struct_time(tm_year=2016, tm_mon=7, tm_mday=13, tm_hour=13, tm_min=1, tm_sec=12, tm_wday=2, tm_yday=195, tm_isdst=0)
>>> time.localtime(os.path.getatime('E:\\a'))
time.struct_time(tm_year=2016, tm_mon=7, tm_mday=13, tm_hour=21, tm_min=1, tm_sec=12, tm_wday=2, tm_yday=195, tm_isdst=0)
exists(path)判断指定路径或文件是否存在
isabs(path)判断制定路径是否是绝对路径
isdir(path)判断制定路径是否存在且是一个目录
isfile(path)。。文件
islink(path)。。符号链接
ismount(path)。。挂载点
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