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

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  Can anyone please help me in resolving the error =>  AttributeError: Array instance has no attribute '__trunc__' bhk755@gmail.com - 2013-04-08 03:07 -0700
    Re: Can anyone please help me in resolving the error => AttributeError: Array instance has no attribute '__trunc__' Dylan Evans <dylan@dje.me> - 2013-04-08 22:40 +1000
      Re: Can anyone please help me in resolving the error => AttributeError: Array instance has no attribute '__trunc__' bhk755@gmail.com - 2013-04-08 23:15 -0700
      Re: Can anyone please help me in resolving the error => AttributeError: Array instance has no attribute '__trunc__' bhk755@gmail.com - 2013-04-08 23:15 -0700
    Re: Can anyone please help me in resolving the error =>  AttributeError: Array instance has no attribute '__trunc__' bhk755@gmail.com - 2013-04-08 21:01 -0700
      Re: Can anyone please help me in resolving the error =>  AttributeError: Array instance has no attribute '__trunc__' Steven D'Aprano <steve+comp.lang.python@pearwood.info> - 2013-04-09 05:14 +0000
        Re: Can anyone please help me in resolving the error =>  AttributeError: Array instance has no attribute '__trunc__' bhk755@gmail.com - 2013-04-08 23:21 -0700
    Re: Can anyone please help me in resolving the error => AttributeError: Array instance has no attribute '__trunc__' Peter Otten <__peter__@web.de> - 2013-04-09 09:57 +0200
      Re: Can anyone please help me in resolving the error => AttributeError: Array instance has no attribute '__trunc__' bhk755@gmail.com - 2013-04-09 01:50 -0700
      Re: Can anyone please help me in resolving the error => AttributeError: Array instance has no attribute '__trunc__' bhk755@gmail.com - 2013-04-09 01:50 -0700
    Re: Can anyone please help me in resolving the error =>  AttributeError: Array instance has no attribute '__trunc__' bhk755@gmail.com - 2013-04-09 01:48 -0700

#43054 — Can anyone please help me in resolving the error => AttributeError: Array instance has no attribute '__trunc__'

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__'

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#43068 — Re: Can anyone please help me in resolving the error => AttributeError: Array instance has no attribute '__trunc__'

[Multipart message — attachments visible in raw view] — view raw

On Mon, Apr 8, 2013 at 8:07 PM, <bhk755@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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#43118 — Re: Can anyone please help me in resolving the error => AttributeError: Array instance has no attribute '__trunc__'

Hi Dylan, 

Thank you for the alternative solution. I will look into that. 

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#43119 — Re: Can anyone please help me in resolving the error => AttributeError: Array instance has no attribute '__trunc__'

Hi Dylan, 

Thank you for the alternative solution. I will look into that. 

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#43110

On Monday, April 8, 2013 3:37:38 PM UTC+5:30, bhk...@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__'


Hi Dylan,

Thank you for the alternative solution. I will look into that. 

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#43114

On Mon, 08 Apr 2013 21:01:04 -0700, bhk755 wrote:


[snip over 260 lines of unnecessary quoted text]
> Hi Dylan,
> 
> Thank you for the alternative solution. I will look into that.


Please trim your replies. There's absolutely no reason to expect people 
to scroll through almost FOUR PAGES of quoted text just to get to a two 
line response.

Thank you.


-- 
Steven

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#43120

Thanks Steven for pointing that out. This is my first topic in Google Groups. So, I did not notice that the previous contents will also be taken in the new post. 

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#43134 — Re: Can anyone please help me in resolving the error => AttributeError: Array instance has no attribute '__trunc__'

bhk755@gmail.com wrote:

> I am trying to create 2D arrays without using advanced features like
> numpy, 

I'd say that using ctypes is a bit more "advanced" than *using* numpy 
because with ctypes it helps to know C.

> for this I have created 2 separate modules arrays.py and
> array2D.py. Here's the code for that:
 
- You should absolutely go with numpy
- If you insist on building your own use lists of lists as suggested
- If you need something more space efficient than lists have a look at 

http://docs.python.org/2/library/array.html

rather than ctypes.

Now on to some debugging, without looking into the details.

> 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 )

Here you create an instance of your array of integers...

>         # 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 )

...and here you are stuffing arrays.Array instances into that array of 
integers. In nuce:

>>> import ctypes
>>> class C: pass # classic class
... 
>>> items = (ctypes.c_int * 3)()
>>> items[0] = C()
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
AttributeError: C instance has no attribute '__trunc__'

ctypes unhelpfully tries to truncate the value to convert it into an 
integer. As an aside here's an example of a successful conversion:

>>> class C2:
...     def __trunc__(self): return 42
... 
>>> items[0] = C2()
>>> items[0]
42

There are basically two resolutions:

- adjust the type of the outer array or
- use a single 1D array internally and calculate the index as
  row * width + column (for example).

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#43142 — Re: Can anyone please help me in resolving the error => AttributeError: Array instance has no attribute '__trunc__'

Awesome Peter!!!. Thanks a lot for detailed explanation...

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#43143 — Re: Can anyone please help me in resolving the error => AttributeError: Array instance has no attribute '__trunc__'

Awesome Peter!!!. Thanks a lot for detailed explanation...

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#43141

Awesome!!! Thanks a lot Peter.

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