Merge branch 'master' of https://github.com/PythonCHB/PythonTopics

Author: PythonCHB

_downloads/CircularReferenceExample.ipynb

@@ -0,0 +1,49 @@
+#!/usr/bin/env python
+
+"""
+sample data for persistence/serializatiion examples
+
+This version is nested, with more stucture 
+  - can be saved with pickle, JSON, xml...
+"""
+
+AddressBook = [ {'first_name': "Chris",
+                 'last_name': "Barker",
+                 'address' : {'line_1':"835 NE 33rd St",
+                              'line_2' : "",
+                              'city' : "Seattle",
+                              'state': "WA",
+                              'zip': "96543"},
+                 'email' : "PythonCHB@gmail.com",
+                 'home_phone' : "206-555-1234",
+                 'office_phone' : "123-456-7890",
+                 'cell_phone' : "234-567-8901",
+                 },
+                
+                {'first_name': "Fred",
+                 'last_name': "Jones",
+                 'address' : {'line_1':"123 SE 13th St",
+                              'line_2' : "Apt. 43",
+                              'city' : "Tacoma",
+                              'state': "WA",
+                              'zip': "93465"},
+                 'email' : "FredJones@some_company.com",
+                 'home_phone' : "510-555-1234",
+                 'office_phone' : "564-466-7990",
+                 'cell_phone' : "403-561-8911",
+                 },
+                
+                {'first_name': "Nancy",
+                 'last_name': "Wilson",
+                 'address' : {'line_1':"8654 Walnut St",
+                              'line_2' : "Suite 567",
+                              'city' : "Pasadena",
+                              'state': "CA",
+                              'zip': "12345"},
+                 'email' : "Wilson.Nancy@gmail.com",
+                 'home_phone' : "423-321-9876",
+                 'office_phone' : "123-765-9877",
+                 'cell_phone' : "432-567-8466",
+                 },
+                ]
+

_downloads/add_book_data.py

@@ -0,0 +1,47 @@
+#!/usr/bin/env python
+
+"""
+sample data for persistence/serialization examples
+this version is flat for saving in CSV, ini, etc.
+"""
+
+AddressBook = [ {'first_name': "Chris",
+                 'last_name': "Barker",
+                 'address_line_1':"835 NE 33rd St",
+                 'address_line_2' : "",
+                 'address_city' : "Seattle",
+                 'address_state': "WA",
+                 'address_zip': "96543",
+                 'email' : "PythonCHB@gmail.com",
+                 'home_phone' : "206-555-1234",
+                 'office_phone' : "123-456-7890",
+                 'cell_phone' : "234-567-8901",
+                 },
+                
+                {'first_name': "Fred",
+                 'last_name': "Jones",
+                 'address_line_1':"123 SE 13th St",
+                 'address_line_2' : "Apt. 43",
+                 'address_city' : "Tacoma",
+                 'address_state': "WA",
+                 'address_zip': "93465",
+                 'email' : "FredJones@some_company.com",
+                 'home_phone' : "510-555-1234",
+                 'office_phone' : "564-466-7990",
+                 'cell_phone' : "403-561-8911",
+                 },
+                
+                {'first_name': "Nancy",
+                 'last_name': "Wilson",
+                 'address_line_1':"8654 Walnut St",
+                 'address_line_2' : "Suite 567",
+                 'address_city' : "Pasadena",
+                 'address_state': "CA",
+                 'address_zip': "12345",
+                 'email' : "Wilson.Nancy@gmail.com",
+                 'home_phone' : "423-321-9876",
+                 'office_phone' : "123-765-9877",
+                 'cell_phone' : "432-567-8466",
+                 },
+                ]
+

_downloads/add_book_data_flat.py

@@ -0,0 +1,89 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+import sys
+import weakref
+import gc
+
+deleted_object_messages = []
+
+
+class MyChild(object):
+    def __init__(self, parent):
+        self.parent = parent
+        #self.parent = weakref.ref(parent)
+        #self.parent = weakref.proxy(parent)
+
+        ## store some data so it will use appreciable memory
+        ## multiply by 1234 to avoid interning
+        self.data = [1234*i for i in range(100000)]
+
+    def __del__(self):
+        deleted_object_messages.append( ('MyChild deleted', id(self)) )
+
+
+class MyParent(object):
+    def __init__(self):
+        self.children = []
+    def addChild(self):
+        child = MyChild(self)
+        self.children.append(child)
+        return child
+    def __del__(self):
+        deleted_object_messages.append( ('MyParent deleted', id(self)) )
+
+if __name__ == "__main__":
+
+    p = MyParent()
+
+    print "refcount for p:", sys.getrefcount(p)
+    assert sys.getrefcount(p) == 2
+
+    a = p.addChild()
+    a2 = p.addChild()
+    print "refcount for p after adding an two children:", sys.getrefcount(p)
+    assert sys.getrefcount(p) == 2
+
+    print "p's children:", p.children
+    assert len(p.children) == 2
+
+    print " a is:", a
+    print "a's parent:", a.parent
+    print "a's parent's children:", a.parent.children
+
+    assert a is a.parent.children[0]
+    assert a2 is a.parent.children[1]
+
+
+    print "a's refcount:", sys.getrefcount(a)
+    assert sys.getrefcount(a) == 3
+
+    print "a2's refcount:", sys.getrefcount(a2)
+    assert sys.getrefcount(a2) == 3
+
+    del p
+    print "after deleting p:"
+
+    print "a's refcount:", sys.getrefcount(a)
+    assert sys.getrefcount(a) == 2
+
+    print "a2's refcount:", sys.getrefcount(a2)
+    assert sys.getrefcount(a2) == 2
+
+    print "deleting a:"
+    id_a = id(a)
+    del a
+    print deleted_object_messages
+    assert deleted_object_messages[-1][0] == 'MyChild deleted'
+    assert deleted_object_messages[-1][1] == id_a
+
+    print "deleting a2:"
+    id_a2 = id(a2)
+    del a2
+    print deleted_object_messages
+    assert deleted_object_messages[-1][0] == 'MyChild deleted'
+    assert deleted_object_messages[-1][1] == id_a2
+
+
+
+

_downloads/circular.py

@@ -0,0 +1,109 @@
+"""
+mem_check.py
+
+functions for getting memoroy use of the current python process
+
+Windows and *nix versions
+
+USAGE:
+
+amount = get_mem_use(units='MB') # options are KB, MB, GB
+
+"""
+
+import sys
+
+div = {'GB': 1024*1024*1024,
+       'MB': 1024*1024,
+       'KB': 1024,
+       }
+
+if sys.platform.startswith('win'):
+
+    """
+
+    Functions for getting memory usage of Windows processes.
+
+    from:
+
+    http://code.activestate.com/recipes/578513-get-memory-usage-of-windows-processes-using-getpro/
+
+    get_mem_use(units='MB') is the one to get memory use for the current process.
+
+
+    """
+    import ctypes
+    from ctypes import wintypes
+
+    GetCurrentProcess = ctypes.windll.kernel32.GetCurrentProcess
+    GetCurrentProcess.argtypes = []
+    GetCurrentProcess.restype = wintypes.HANDLE
+
+    SIZE_T = ctypes.c_size_t
+
+    class PROCESS_MEMORY_COUNTERS_EX(ctypes.Structure):
+        _fields_ = [
+            ('cb', wintypes.DWORD),
+            ('PageFaultCount', wintypes.DWORD),
+            ('PeakWorkingSetSize', SIZE_T),
+            ('WorkingSetSize', SIZE_T),
+            ('QuotaPeakPagedPoolUsage', SIZE_T),
+            ('QuotaPagedPoolUsage', SIZE_T),
+            ('QuotaPeakNonPagedPoolUsage', SIZE_T),
+            ('QuotaNonPagedPoolUsage', SIZE_T),
+            ('PagefileUsage', SIZE_T),
+            ('PeakPagefileUsage', SIZE_T),
+            ('PrivateUsage', SIZE_T),
+        ]
+
+    GetProcessMemoryInfo = ctypes.windll.psapi.GetProcessMemoryInfo
+    GetProcessMemoryInfo.argtypes = [
+        wintypes.HANDLE,
+        ctypes.POINTER(PROCESS_MEMORY_COUNTERS_EX),
+        wintypes.DWORD,
+    ]
+    GetProcessMemoryInfo.restype = wintypes.BOOL
+
+    def get_current_process():
+        """Return handle to current process."""
+        return GetCurrentProcess()
+
+    def get_memory_info(process=None):
+        """Return Win32 process memory counters structure as a dict."""
+        if process is None:
+            process = get_current_process()
+        counters = PROCESS_MEMORY_COUNTERS_EX()
+        ret = GetProcessMemoryInfo(process, ctypes.byref(counters),
+                                   ctypes.sizeof(counters))
+        if not ret:
+            raise ctypes.WinError()
+        info = dict((name, getattr(counters, name))
+                    for name, _ in counters._fields_)
+        return info
+
+    def get_mem_use(units='MB'):
+        """
+        returns the total memory use of the current python process
+
+        :param units='MB': the units you want the reslut in. Options are:
+                           'GB', 'MB', 'KB'
+        """
+        info = get_memory_info()
+        return info['PrivateUsage'] / float(div[units])
+
+
+else: # for posix systems only tested on OS-X for now
+    def get_mem_use(units='MB'):
+        """
+        returns the total memory use of the current python process
+
+        :param units='MB': the units you want the reslut in. Options are:
+                           'GB', 'MB', 'KB'
+        """
+        import resource
+        #useage = resource.getrusage(resource.RUSAGE_SELF).ru_maxrss
+        div = {'GB': 1024*1024*1024,
+               'MB': 1024*1024,
+               'KB': 1024,
+               }
+        return resource.getrusage(resource.RUSAGE_SELF).ru_maxrss / float(div[units])

_downloads/mem_check.py

@@ -0,0 +1,58 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+"""
+a simple test of a circular reference that gc.collect() will not clean up.
+
+And watch the memory grow!
+
+"""
+
+
+import sys
+import gc
+import weakref
+
+import mem_check
+
+
+class MyChild(object):
+    def __init__(self, parent):
+        #self.parent = parent
+        # if a weak ref is used, then no memory leak.
+        self.parent = weakref.proxy(parent)
+
+        ## store some data so it will use appreciable memory
+        ## multiply by 1234 to reduce interning
+        self.data = [1234*i for i in range(100000)]
+
+    def __del__(self):
+        """ __del__ defined to defeat GC"""
+        print 'MyChild deleted', id(self)
+
+
+class MyParent(object):
+    def __init__(self):
+        self.children = []
+    def addChild(self):
+        child = MyChild(self)
+        self.children.append(child)
+        return child
+    def __del__(self):
+        """ __del__ defined to defeat GC"""
+        print 'MyParent deleted', id(self)
+
+
+if __name__ == "__main__":
+
+    # create a bunch in a loop:
+    for i in range(50):
+        print "iteration:", i
+        p = MyParent()
+        p.addChild()
+        p.addChild()
+        p.addChild()
+        print "ref count:", sys.getrefcount(p)
+        print "mem_use: %f MB"%mem_check.get_mem_use()
+        del p
+        print "collected", gc.collect()

_downloads/memcount.py

@@ -0,0 +1,39 @@
+#!/usr/bin/env python
+
+"""
+Simple contrived example of circular reference counting
+"""
+
+import sys
+
+l1 = [1,]
+l2 = [2,]
+
+l1_id = id(l1)
+l2_id = id(l2)
+
+print "initial ref counts:"
+print "l1:", sys.getrefcount(l1)
+print "l2:", sys.getrefcount(l2)
+
+print "now add the circular references:"
+l1.append(l2)
+l2.append(l1)
+
+print "ref counts after the circular reference is added"
+print "l1:", l1, "refcount:", sys.getrefcount(l1)
+print "l2:", l2, "refcount:", sys.getrefcount(l2)
+
+print "delete one"
+del l1
+print "l2:", sys.getrefcount(l2)
+
+print "delete the other"
+del l2
+
+print "but are they still there???"
+
+
+
+
+