Can anyone please help me in resolving the error => AttributeError: Array instance has no attribute '__trunc__'

[Dylan Evans]

On Mon, Apr 8, 2013 at 8:07 PM, <bhk755 at gmail.com> wrote:

> I am trying to create 2D arrays without using advanced features like
> numpy, for this I have created 2 separate modules arrays.py and array2D.py.
> Here's the code for that:
>
> arrays.py module:
> ==================
> import ctypes
>
> class Array:
>
> #Creates an array with size elements.
>     def __init__( self, size ):
>         assert size > 0, "Array size must be > 0"
>         self._size = size
>         print "sixe is %s" %self._size
>
>  # Create the array structure using the ctypes module.
>         PyArrayType = ctypes.c_int * size
>         self._elements = PyArrayType()
>         print "type is e", type(self._elements)
>         #self._elements = ctypes.c_int * size
>
>         print "Elements are self.element %s" % self._elements
> # Initialize each element.
>         #for i in range(self._size):
>         #       self.clear( i )
>
>
> # Returns the size of the array.
>     def __len__( self ):
>         return self._size
>
> # Gets the contents of the index element.
>     def __getitem__( self, index ):
>         assert index >= 0 and index < len(self), "Array subscript out of
> range"
>         return self._elements[ index ]
>
> # Puts the value in the array element at index position.
>     def __setitem__( self, index, value ):
>         assert index >= 0 and index < len(self), "Array subscript out of
> range"
>         print "Type is ", type(index)
>         self._elements[ index ] = value
>
> # Clears the array by setting each element to the given value.
>     def clear( self, value ):
>         for i in range( len(self) ) :
>         self._elements[i] = value
>
> # Printing the arrays:
>     def __str__(self):
>         return self._elements
>
>
>
> array2D.py module
> ==================
>
>
> import arrays
>
> class Array2D :
>     # Creates a 2-D array of size numRows x numCols.
>     def __init__( self, numRows, numCols ):
>     # Create a 1-D array to store an array reference for each row.
>
>         self._theRows = arrays.Array( numRows )
>         # Create the 1-D arrays for each row of the 2-D array.
>         print "Num of Cloumns is", numCols
>
>         for i in range( numRows ) :
>             self._theRows[i] = arrays.Array( numCols )
>
>     # Returns the number of rows in the 2-D array.
>     def numRows( self ):
>         return len( self._theRows )
>
>     # Returns the number of columns in the 2-D array.
>     def numCols( self ):
>         return len( self._theRows[0] )
>
>     # Clears the array by setting every element to the given value.
>     def clear( self, value ):
>         for row in range( self.numRows() ):
>             row.clear( value )
>
>     # Gets the contents of the element at position [i, j]
>     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]
>
>     # Sets the contents of the element at position [i,j] to value.
>     def __setitem__( self, ndxTuple, value ):
>         #assert len(ndxTuple) == 3, "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
>
>
> arr = Array2D(2,4)
>
> print "arr is %s" %arr
>
>
> Traceback is :
>
> sixe is 2
> type is e <class 'arrays.c_long_Array_2'>
> Elements are self.element <arrays.c_long_Array_2 object at 0x00AA7F80>
> Cols in 4
> Num of Cloumns is 4
> !!!!!!!!!!!!!! i is 0
> sixe is 4
> type is e <class 'arrays.c_long_Array_4'>
> Elements are self.element <arrays.c_long_Array_4 object at 0x00B60210>
> Type is  <type 'int'>
> Traceback (most recent call last):
>   File "C:\Python27\Lib\array2D.py", line 53, in <module>
>     arr = Array2D(2,4)
>   File "C:\Python27\Lib\array2D.py", line 16, in __init__
>     self._theRows[i] = arrays.Array( numCols )
>   File "C:\Python27\Lib\arrays.py", line 36, in __setitem__
>     self._elements[ index ] = value
> AttributeError: Array instance has no attribute '__trunc__'
> --
> http://mail.python.org/mailman/listinfo/python-list
>


Not sure about the __trunc__ problem but i can suggest this alternative
which is a bit simpler

def array2D(x, y, val=None):
    return [[val for col in xrange(x)] for row in xrange(y)]


-- 
"The UNIX system has a command, nice ... in order to be nice to the other
users. Nobody ever uses it." - Andrew S. Tanenbaum
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