Arrays/Python/CompactArrays - Revision history

Admin: /* The Output */

2017-05-29T05:30:09Z

The Output

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Admin at 05:29, 29 May 2017

2017-05-29T05:29:52Z

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Admin at 05:29, 29 May 2017

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Admin at 05:29, 29 May 2017

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	Size of array with 1000 elements: 4056		Size of array with 1000 elements: 4056
	</pre>		</pre>

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Admin at 05:29, 29 May 2017

2017-05-29T05:29:11Z

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	Compact arrays of such structures should be created with lower-level support of module called ctypes.		Compact arrays of such structures should be created with lower-level support of module called ctypes.

			===The Code===

			<pre>
			import sys
			from array import array

			"""
			Goodrich et al
			Data Structures in Python
			Chapter 5: Array-Based Sequences

			Exploring the use of compact arrays.
			"""

			n = int(1E3)
			slow = [j for j in range(n)]
			fast = array('i',[j for j in range(n)])
			for i,j in zip(["list","array"],[slow,fast]):
			print("Size of {0} with {1} elements: {2:4d}".format(i,n,sys.getsizeof(j)))

			</pre>

			===The Output===

			<pre>
			$ python arraytype.py
			Size of list with 1000 elements: 9032
			Size of array with 1000 elements: 4056
			</pre>

Admin: Created page with "Compact arrays: To save space when implementing integer or double arrays, don't make them referential arrays. This can use 4-5 times more space. Instead, use compact arrays,..."

2017-05-29T05:28:14Z

Created page with "Compact arrays: To save space when implementing integer or double arrays, don't make them referential arrays. This can use 4-5 times more space. Instead, use compact arrays,..."

New page

Compact arrays:

To save space when implementing integer or double arrays, don't make them referential arrays. This can use 4-5 times more space. Instead, use compact arrays, from the arrays submodule. This requires specifying the type of the array.

<pre>
primes = array('i', [2,3,57,11,13,17,19])
</pre>

Valid codes:
* b signed char 1 bit
* B unsigned char 1 bit
* u unicode char 2 bit or 4 bit
* h signed short int 2 bit
* H unsigned short int 2 bit
* i signed int 2 or 4 bit
* I unsigned int 2 or 4 bit
* l signed long int 4 bit
* L unsigned long int 4 bit
* f float 4 bit
* d float 8 bit

This only works with the built-in types mentioned above. User-defined data types cannot be used with compact arrays.

Compact arrays of such structures should be created with lower-level support of module called ctypes.