Python 2.6 快速参考指南：核心概念与模块解析

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"Python 2.6 Quick Reference (Letter) (2009).pdf" 这份文档是关于Python 2.6版本的快速参考指南，旨在帮助用户迅速查阅和理解Python 2.6的关键概念、语法和内置功能。以下是该文档涵盖的一些主要知识点： 1. **调用选项(Invocation Options)**：这部分介绍了如何启动Python解释器，以及可能的命令行选项，这些选项可以影响解释器的行为。 2. **环境变量(Environment Variables)**：环境变量对Python的运行环境有重要影响，如设置路径、配置等。 3. **词法实体(Lexical Entities)**：包括关键字（如`if`, `for`, `while`等）、标识符（变量名、函数名等）、字符串字面量、布尔常量（`True`和`False`）、数字、序列（如列表和元组）、字典、运算符等。 4. **基本类型及操作(Basic Types and Their Operations)**：涵盖了NoneType（None）、布尔类型（bool）、数值类型（int, long, float等）、序列类型（list, tuple）、字典（dictionary）、字符串（string）、文件对象、集合（set）和命名元组（namedtuple）。同时也详细列出了这些类型的相关操作，如索引、切片、连接、乘法、比较等。 5. **高级类型(Advanced Types)**：包括了Python中更复杂的数据结构和概念，可能包括元类、迭代器、生成器、描述符和装饰器。 6. **语句(Statements)**：涉及赋值语句、条件表达式、控制流（如循环、分支）、异常处理、命名空间、函数定义（`def`）和类定义（`class`）。 7. **迭代器(Iterators)**：迭代器允许遍历任何可迭代对象，如列表、字符串或生成器。 8. **生成器(Generators)**：生成器是一种特殊的迭代器，可以通过`yield`语句在函数内部创建，实现延迟计算和记忆化。 9. **描述符(Descriptors)**：描述符是实现了属性访问协议的对象，它们可以用来控制类属性的行为。 10. **装饰器(Decorators)**：装饰器允许在不修改已有函数代码的情况下扩展其功能。 11. **内置函数(Built-in Functions)**：如`len()`, `range()`, `type()`, `map()`, `zip()`等，这些都是Python提供的一系列预定义函数。 12. **内置异常(Built-in Exceptions)**：包括了如`SyntaxError`, `TypeError`, `KeyError`等常见的错误类型。 13. **标准方法和操作符重载(Standard Methods & Operators Redefinition in User-Created Classes)**：用户自定义类可以重写内置类型的方法，如`__add__`, `__mul__`等，实现自定义的加法、乘法等操作。 14. **特殊状态属性(Special Informative State Attributes for Some Types)**：某些类型的对象具有特定的属性，可以提供有关对象状态的信息。 15. **重要模块(Important Modules)**：文档列举了一些核心模块，如`sys`（系统相关）、`os`（操作系统接口）、`posix`、`posixpath`（路径操作）、`shutil`（文件操作）、`time`（时间操作）、`string`（字符串操作）、`re`（正则表达式）、`math`（数学函数）和`getopt`（命令行选项解析）。 16. **基础分发中的模块(List of Modules in the Base Distribution)**：给出了Python 2.6基础安装中包含的所有模块列表。 17. **工作区探索和编程习惯提示(Workspace Exploration and Idiom Hints)**：提供了如何有效利用Python开发环境以及一些常用的编程模式和技巧。 18. **Python在Emacs中的模式(Python Mode for Emacs)**：介绍了在Emacs编辑器中使用Python的特定模式，以提升开发效率。文档最后提到了更新和错误报告的途径，以及版本历史，显示了文档随着时间的推移不断更新和改进的过程。这个PDF是学习和参考Python 2.6版本编程的宝贵资源，尤其对于那些需要快速查找语言特性和API的开发者来说。

Notes:



(1) Raises a ValueError exception when x is not found in s (i.e. out of range).



(2) The sort() method takes an optional argument cmp specifying a comparison function takings 2 list items and

returning -1, 0, or 1 depending on whether the 1st argument is considered smaller than, equal to, or larger

than the 2nd argument. Note that this slows the sorting process down considerably. Since 2.4, the cmp

argument may be specified as a keyword, and 2 optional keywords args are added: key is a fct that takes a list

item and returns the key to use in the comparison (faster than cmp); reverse: If True, reverse the sense of

the comparison used.

Since Python 2.3, the sort is guaranteed "stable". This means that two entries with equal keys will be returned

in the same order as they were input. For example, you can sort a list of people by name, and then sort the list

by age, resulting in a list sorted by age where people with the same age are in name-sorted order.



(3) The sort() and reverse() methods modify the list in place for economy of space when sorting or

reversing a large list. They don't return the sorted or reversed list to remind you of this side effect.



(4) The pop() method is not supported by mutable sequence types other than lists. The optional argument i

defaults to -1, so that by default the last item is removed and returned.



(5) Raises a TypeError when x is not a list object.

Notes:



TypeError is raised if key is not acceptable.



(1) KeyError is raised if key k is not in the map.



(2) Keys and values are listed in random order.



(3) Never raises an exception if k is not in the map, instead it returns defaultval. defaultval is optional, when

not provided and k is not in the map, None is returned.



(4) Never raises an exception if k is not in the map, instead returns defaultVal, and adds k to map with value

defaultVal. defaultVal is optional. When not provided and k is not in the map, None is returned and added to

map.

Ope r a t io n s o n m ap pi n g s / d i c t io n a r i es ( ty p e d i c t )

Operations on mappings

Operation Result Notes

len(d) The number of items in d

dict()

dict(**kwargs)

dict(iterable)

dict(d)

Creates an empty dictionary.

Creates a dictionary init with the keyword args

kwargs.

Creates a dictionary init with (key, value) pairs

provided by iterable.

Creates a dictionary which is a copy of dictionary d.

d.fromkeys(iterable, value=None) Class method to create a dictionary with keys

provided by iterator, and all values set to value.

d[k] The item of d with key k (1)

d[k] = x Set d[k] to x

del d[k] Removes d[k] from d (1)

d.clear() Removes all items from d

d.copy() A shallow copy of d

d.has_key(k)

k in d

True if d has key k, else False

d.items() A copy of d's list of (key, item) pairs (2)

d.keys() A copy of d's list of keys (2)

d1.update(d2)

for k, v in

.items():

[k] = v

Since 2.4, update(**kwargs) and update(iterable)

may also be used.

d.values() A copy of d's list of values (2)

d.get(k, defaultval) The item of d with key k (3)

d.setdefault(k[,defaultval]) d[k] if k in d, else defaultval(also setting it) (4)

d.iteritems() Returns an iterator over (key, value) pairs.

d.iterkeys() Returns an iterator over the mapping's keys.

d.itervalues() Returns an iterator over the mapping's values.

d.pop(k[, default]) Removes key k and returns the corresponding value.

If key is not found, default is returned if given,

otherwise KeyError is raised.

d.popitem() Removes and returns an arbitrary (key, value) pair

from d

Python 2.6 Quick Reference

Page

These string methods largely (but not completely) supersede the functions available in the string module.

The str and unicode types share a common base class basestring.

Ope r a t io n s o n s tr i ng s ( t y p e s s t r & u n i c o d e )

Operations on strings

Operation Result Notes

s.capitalize() Returns a copy of s with its first character capitalized, and the rest of the

characters lowercased.

s.center(width[,

fillChar=' '])

Returns a copy of s centered in a string of length width, surrounded by the

appropriate number of fillChar characters.

(1)

s.count(sub[, start[,

end]])

Returns the number of occurrences of substring sub in string s. (2)

s.decode([encoding[,

errors]])

Returns a unicode string representing the decoded version of str s, using

the given codec (encoding). Useful when reading from a file or a I/O

function that handles only str. Inverse of encode.

(3)

s.encode([encoding[,

errors]])

Returns a str representing an encoded version of s. Mostly used to

encode a unicode string to a str in order to print it or write it to a file

(since these I/O functions only accept str), e.g. u'légère'.encode

('utf8'). Also used to encode a str to a str, e.g. to zip (codec 'zip') or

uuencode (codec 'uu') it. Inverse of decode.

(3)

s.endswith(suffix [,

start[, end]])

Returns True if s ends with the specified suffix, otherwise return false.

Since 2.5 suffix can also be a tuple of strings to try.

(2)

s.expandtabs

([tabsize])

Returns a copy of s where all tab characters are expanded using spaces. (4)

s.find(sub [,start

[,end]])

Returns the lowest index in s where substring sub is found. Returns -1 if

sub is not found.

(2)

s.format(*args,

*kwargs)

Returns s after replacing numeric and named formatting references found

in braces {}. (details)

s.index(sub[, start[,

end]])

like find(), but raises ValueError when the substring is not found. (2)

s.isalnum() Returns True if all characters in s are alphanumeric, False otherwise. (5)

s.isalpha() Returns True if all characters in s are alphabetic, False otherwise. (5)

s.isdigit() Returns True if all characters in s are digit characters, False otherwise. (5)

s.islower() Returns True if all characters in s are lowercase, False otherwise. (6)

s.isspace() Returns True if all characters in s are whitespace characters, False

otherwise.

(5)

s.istitle() Returns True if string s is a titlecased string, False otherwise. (7)

s.isupper() Returns True if all characters in s are uppercase, False otherwise. (6)

separator.join(seq) Returns a concatenation of the strings in the sequence seq, separated by

string separator, e.g.: ",".join(['A', 'B', 'C']) -> "A,B,C"

s.ljust/rjust/center

(width[, fillChar=' '])

Returns s left/right justified/centered in a string of length width. (1), (8)

s.lower() Returns a copy of s converted to lowercase.

s.lstrip([chars] ) Returns a copy of s with leading chars (default: blank chars) removed.

s.partition(separ) Searches for the separator separ in s, and returns a tuple (head, sep,

tail) containing the part before it, the separator itself, and the part after

it. If the separator is not found, returns (s, '', '').

s.replace(old, new[,

maxCount =-1])

Returns a copy of s with the first maxCount (-1: unlimited) occurrences of

substring old replaced by new.

(9)

s.rfind(sub[ , start[,

end]])

Returns the highest index in s where substring sub is found. Returns -1 if

sub is not found.

(2)

s.rindex(sub[ , start[,

end]])

like rfind(), but raises ValueError when the substring is not found. (2)

s.rpartition(separ) Searches for the separator separ in s, starting at the end of s, and returns

a tuple (head, sep, tail) containing the (left) part before it, the

separator itself, and the (right) part after it. If the separator is not found,

returns ('', '', s).

s.rstrip([chars]) Returns a copy of s with trailing chars(default: blank chars) removed, e.g.

aPath.rstrip('/') will remove the trailing '/'from aPath if it exists

s.split([ separator[,

maxsplit]])

Returns a list of the words in s, using separator as the delimiter string. (10)

Python 2.6 Quick Reference

Page

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