数组Array

数组Array是最基本的数据结构，在内存中为一段定长连续内存,很多编程语言都有实现。

一、一维数组

下面代码实现了一维数组和它的遍历。

clear并非清空数组，而是采用具体值对数组进行初始化。

import ctypes

class Array :

    def __init__( self, size ):

        assert size > 0, "Array size must be > 0"

        self._size = size

        PyArrayType = ctypes.py_object * size

        self._elements = PyArrayType()

        self.clear( None )

    def __len__( self ):

        return self._size

    def __getitem__( self, index ):

        assert index >=0 and index < len(self), "Array subscript out of range"

        return self._elements[ index ]

    def __setitem__( self, index, value ):

        assert index >=0 and index < len(self), "Array subscript out of range"

        self._elements[ index ] = value

    def clear( self, value ):

        for i in range( len(self) ) :

            self._elements[i] = value

    def __iter__( self ):

        return _ArrayIterator( self._elements )

class _ArrayIterator :

    def __init__( self, theArray ):

        self._arrayRef = theArray

        self._curNdx = 0

    def __iter__( self ):

        return self

    def __next__( self ):

        if self._curNdx < len( self._arrayRef ) :

            entry = self._arrayRef[ self._curNdx ]

            self._curNdx += 1

            return entry

        else :

            raise StopIteration

if __name__=='__main__':

    myarray=Array(5)

    myarray.clear(1)

    myarray.__setitem__(2,5)

    print myarray.__getitem__(2)

    it=myarray.__iter__()

    while True:

        try:

            print it.__next__()

        except StopIteration:

            break

二、二维数组

二维数组的构造基于一维数组Array，它可以看做是一个以行数为size的一维数组，区别在于数组中的每个元素并不是具体的值，而是由以列数为size的数组构成。如下图所示：

class Array2D :

    def __init__( self, numRows, numCols ):

        self._theRows = Array( numRows )

        for i in range( numRows ) :

            self._theRows[i] = Array( numCols )

    def numRows( self ):

        return len( self._theRows )

    def numCols( self ):

        return len( self._theRows[0] )

def __getitem__( self, ndxTuple ):

        assert len(ndxTuple) == 2, "Invalid number of array subscripts."

        row = ndxTuple[0]

        col = ndxTuple[1]

        assert row >=0 and row < self.numRows() and col >=0 and col < self.numCols(), "Array subscript out of range."

        the1dArray = self._theRows[row]

        return the1dArray[col]

    def __setitem__( self, ndxTuple, value ):

        assert len(ndxTuple) == 2, "Invalid number of array subscripts."

        row = ndxTuple[0]

        col = ndxTuple[1]

        assert row >=0 and row < self.numRows() and col >=0 and col < self.numCols(), "Array subscript out of range."

        the1dArray = self._theRows[row]

        the1dArray[col] = value

巴特西

数组Array

一、一维数组

二、二维数组

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