【转】python之模块array

【转】python之模块array

>>> import array#定义了一种序列数据结构
>>> help(array)  
  #创建数组,相当于初始化一个数组,如:d={},k=[]等等
array(typecode [, initializer]) -- create a new array
  #a=array.array('c'),决定着下面操作的是字符,并是单个字符
  #a=array.array('i'),决定着下面操作的是整数
| Attributes:
|
| typecode -- the typecode character used to create the array
| itemsize -- the length in bytes of one array item
|
| Methods defined here:
| •append(...)
| append(x)
| #向array数组添加一个数值value
| Append new value x to the end of the array.

        >>> a=array.array('i')#整数,b与i类似
        >>> a.append(8)
        >>> a.append(81)
        >>> a
        array('i', [8, 81])#构成list 

        >>> a=array.array('c')#单个字符

        >>> a.append('g')
        >>> a.append('g')
        >>> a
        array('c', 'gg')#单个字符连接

        >>> a=array.array('u')#Unicode character,意味着下面将要输入的是unicode字符串.
        >>> a.append(u'x')#不要漏掉u
        >>> a.append(u'x')
        >>> a
        array('u', u'xx')

|
| •buffer_info(...)
| buffer_info() -> (address, length)#当前内存地址和数组长度
       #返回一个元组(地址,长度),给出了当前的内存地址和用于存储数组内容的缓冲区的长度

        >>> a.buffer_info()
        (19225728, 7)

     |      Return a tuple (address, length) giving the current memory address and
| the length in items of the buffer used to hold array's contents
| The length should be multiplied by the itemsize attribute to calculate
| the buffer length in bytes.
|
| byteswap(...)
| byteswap()
|
| Byteswap all items of the array. If the items in the array are not 1, 2,
| 4, or 8 bytes in size, RuntimeError is raised.
|
| •count(...)
| count(x)    #统计array数组中某个元素(x)的个数.

        >>> a
        array('i', [9, 2, 9, 4, 10, 10, 10])
        >>> a.count(10)
        3
        >>> a.count(9)
        2

     |      Return number of occurrences of x in the array.
|
| •extend(...)
| extend(array or iterable)  #参数接受 数组和可迭代对象

        >>> a
        array('i', [9, 2, 9, 4, 10, 10, 10])
        >>> a.extend([3,5])
        >>> a
        array('i', [9, 2, 9, 4, 10, 10, 10, 3, 5])

        #如果添加整数会出现什么错误?

        >>> a.extend(10)

        Traceback (most recent call last):
        File "<pyshell#131>", line 1, in <module>
        a.extend(10)
        TypeError: 'int' object is not iterable  #int不是可迭代对象

     |      Append items to the end of the array.#在末尾添加数组或可迭代对象
|
| fromfile(...)
| fromfile(f, n)
|
| Read n objects from the file object f and append them to the end of the
| array. Also called as read.
|
| fromlist(...)
| fromlist(list)
|
| Append items to array from list.
|
| fromstring(...)
| fromstring(string)
|
| Appends items from the string, interpreting it as an array of machine
| values,as if it had been read from a file using the fromfile() method).
|
| fromunicode(...)
| fromunicode(ustr)
|
| Extends this array with data from the unicode string ustr.
| The array must be a type 'u' array; otherwise a ValueError
| is raised. Use array.fromstring(ustr.decode(...)) to
| append Unicode data to an array of some other type.
|
| index(...)
| index(x)
|
| Return index of first occurrence of x in the array.
|
| •insert(...)
| insert(i,x)  #在i的位置插入一个新的item在array中
|
| Insert a new item x into the array before position i.
|
| •pop(...)
| pop([i])

        >>> a=array.array('i')
        >>> a.append(2)
        >>> a.append(9)
        >>> a.append(3)
        >>> a
        array('i', [2, 9, 3])
        >>> a.pop()#默认删除索引为-1的元素,最后一个元素,如果传参数则按参数索引来删除元素.
        3
        >>> a
        array('i', [2, 9])

     |      Return the i-th element and delete it from the array. i defaults to -1.
|
| read(...)
| fromfile(f, n)
|
| Read n objects from the file object f and append them to the end of the
| array. Also called as read.
|
| •remove(...)
| remove(x)#删除指定元素,x为需要删除的元素.
| Remove the first occurrence of x in the array.
|
| reverse(...)
| reverse()
|
| Reverse the order of the items in the array.
|
| tofile(...)
| tofile(f)
|
| Write all items (as machine values) to the file object f. Also called as
| write.
|
| •tolist(...)
| tolist() -> list

        a=array('i', [9, 2, 9, 4, 10, 10, 10, 3, 5])
        >>> a.list()

        a.list()
        AttributeError: 'array.array' object has no attribute 'list'#array.array没有list属性
        >>> a.tolist()
        [9, 2, 9, 4, 10, 10, 10, 3, 5]

     |      Convert array to an ordinary list with the same items.
|
| •tostring(...)
| tostring() -> string

        array('i', [9, 2, 9, 4])
        >>> a.tostring()    #转化为string
        '\t\x00\x00\x00\x02\x00\x00\x00\t\x00\x00\x00\x04\x00\x00\x00'

     |  •tounicode(...)
| tounicode() -> unicode #将unicode的array数组,转化为unicode string字符串。

        >>> a=array.array('u')
        >>> a.append(u'xiaodeng')

        a.append(u'xiaodeng')
        TypeError: array item must be unicode character
        >>> a.append(u'x')
        >>> a.append(u'i')
        >>> a.tounicode()
        u'xi'

|
| write(...)
| tofile(f)
|
| Write all items (as machine values) to the file object f. Also called as
| write.
|
| ----------------------------------------------------------------------
| Data descriptors defined here:
|
| itemsize
| the size, in bytes, of one array item
|
| typecode
| the typecode character used to create the array
|
| ----------------------------------------------------------------------

Type code   C Type         Minimum size in bytes#最小字节大小
'c'      character (字符,单个字符)       1
'b'      signed integer     1
'B'      unsigned integer    1
'u'      Unicode character   2
'h'      signed integer     2
'H'      unsigned integer    2
'i'      signed integer     2
'I'      unsigned integer    2
'l'      signed integer     4
'L'      unsigned integer    4
'f'      floating point     4
'd'      floating point     8

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