Python学习记录——基本概念

Python数据类型：

在Python中有三种内建的数据结构——列表、元组和字典。

命令：help （list）

列表：list

week = [ 'Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday' ]

week.append('Sunday')

class list(object)
|  list() -> new empty list
|  list(iterable) -> new list initialized from iterable's items

元组：tuple

tuple和list类似，但tuple是只读的，就像字符串，定义完就不可以修改了。

week = ('Monday', 'Tuesday', 'Wednesday', 'Thursday', 'Friday', 'Saturday', 'Sunday' )

class tuple(object)
|  tuple() -> empty tuple
|  tuple(iterable) -> tuple initialized from iterable's items
|
|  If the argument is a tuple, the return value is the same object.
|

字典：dict（dictionary）

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:

字符串：str（string）

class str(basestring)
|  str(object) -> string
|
|  Return a nice string representation of the object.
|  If the argument is a string, the return value is the same object.
|
|  Method resolution order:
|      str
|      basestring
|      object

unicode：

class unicode(basestring)
|  unicode(string [, encoding[, errors]]) -> object
|
|  Create a new Unicode object from the given encoded string.
|  encoding defaults to the current default string encoding.
|  errors can be 'strict', 'replace' or 'ignore' and defaults to 'strict'.
|
|  Method resolution order:
|      unicode
|      basestring
|      object

集合：set

class set(object)
|  set() -> new empty set object
|  set(iterable) -> new set object
|
|  Build an unordered collection of unique elements.

只读集合？：frozenset （貌似这个集合创建后不能修改）

class frozenset(object)
|  frozenset() -> empty frozenset object
|  frozenset(iterable) -> frozenset object
|
|  Build an immutable unordered collection of unique elements.

2. 类的默认函数

__init__ 初始化的时候被创建。

__call__ 使得类地对象（注意是对象）具有callable功能，可以把对象当函数使用，如：A a; a()

__str__ 该函书必须返回字符串，可以用str(object)将非字符从转化为字符串，print的时候会调用该函书。

3. 内建函数

repr(...)

repr(object) -> string //obj==eval(repr(obj))