Python3基础-语言内置

Python3基础-语言内置

节选自Python文档的Library Reference部分，位置：

Python » 3.4.3 Documentation » The Python Standard Library »

Built-in Functions 内置函数

部分例如：

函数	例子
bin()	bin(5) => ‘0b101’
chr()	chr(27721) => ‘汉’
dict()
eval()	x=3, eval(‘x+1’) => 4
hex()
id()
int()
len()
list()
ord()	ord(‘汉’) => 27721
range()
repr()	repr(100) => ‘100’
str()	str(100) => ‘100’
tuple()
type()	type((6,)) => <class ‘tuple’>

Built-in Constants 内置常量

• True
• False
• None
• NotImplemented
• 等

Built-in Types 内置类型

Truth Value Testing真值测试

下面的值被当作false看待：

• None
• False
• zero of any numeric type, for example, 0, 0.0, 0j.
• any empty sequence, for example, '', (), [].
• any empty mapping, for example, {}.
• 等

Boolean Operations布尔操作

• or
• and
• not

Comparisons比较

Operation	Meaning
<	strictly less than
<=	less than or equal
>	strictly greater than
>=	greater than or equal
==	equal
!=	not equal
is	object identity
is not	negated object identity

Numeric Types — int, float, complex 三种数值类型

三种数值类型: integers整数, floating point numbers浮点数, and complex numbers复数. In addition, Booleans are a subtype of integers.

The constructors int(), float(), and complex() can be used to produce numbers of a specific type.

Bitwise Operations on Integer Types

作用于整数上的位运算：

Operation	Result
x l y	bitwise or of x and y
x ^ y	bitwise exclusive or of x and y
x & y	bitwise and of x and y
x << n	x shifted left by n bits
x >> n	x shifted right by n bits
~x	the bits of x inverted

Iterator Types 迭代器类型

略

Sequence Types — list, tuple, range 三种序列类型

class list([iterable])

Lists may be constructed in several ways:

• Using a pair of square brackets to denote the empty list: []
• Using square brackets, separating items with commas: [a], [a, b, c]
• Using a list comprehension: [x for x in iterable]
• Using the type constructor: list() or list(iterable)

class tuple([iterable])

Tuples may be constructed in a number of ways:

• Using a pair of parentheses to denote the empty tuple: ()
• Using a trailing comma for a singleton tuple: a, or (a,)
• Separating items with commas: a, b, c or (a, b, c)
• Using the tuple() built-in: tuple() or tuple(iterable)

class range(start, stop[, step])

例：

>>> list(range(0, 10, 3))
[0, 3, 6, 9]

Text Sequence Type — str 文本序列类型

• Single quotes: ‘allows embedded “double” quotes’
• Double quotes: “allows embedded ‘single’ quotes”.
• Triple quoted: ”’Three single quotes”’, “”“Three double quotes”“”

Binary Sequence Types — bytes, bytearray, memoryview 三种二进制序列类型

略

Set Types — set, frozenset 两种集合类型

略

Mapping Types — dict 映射类型

略

Built-in Exceptions 内置异常

略