cpython

I learnt that in some immutable classes, __new__ may return an existing instance - this is what the int , str and tuple types sometimes do for small values. But why do the following two snippets differ in the behavior? With a space at the end: >>> a = 'string ' >>> b = 'string ' >>> a is b False Without a space: >>> c = 'string' >>> d = 'string' >>> c is d True Why does the space bring the difference? This is a quirk of how the CPython implementation chooses to cache string literals. String literals with the same contents may refer to the same string object, but they don't have to. 'string'

how can I load a c# dll in python? Do I have to put some extra code in the c# files? (like export in c++ files) I don't want to use IronPython. I want to import a module to Python! Vivek Bernard This is to answer the second part of your Question Try making the DLL COM visible. by using the [ComVisible(true)] Ok IronPython is a .net implemenatation of the Python language The technology is going to use the DLR of the .net 4.0 when it arrives so IronPython will have more Dynamism (is that a word). (In english if you're a Python guru, you'll feel more at home when you use IronPython) So you may

So i was playing with list objects and found little strange thing that if list is created with list() it uses more memory, than list comprehension? I'm using Python 3.5.2 In [1]: import sys In [2]: a = list(range(100)) In [3]: sys.getsizeof(a) Out[3]: 1008 In [4]: b = [i for i in range(100)] In [5]: sys.getsizeof(b) Out[5]: 912 In [6]: type(a) == type(b) Out[6]: True In [7]: a == b Out[7]: True In [8]: sys.getsizeof(list(b)) Out[8]: 1008 From the docs : Lists may be constructed in several ways: Using a pair of square brackets to denote the empty list: [] Using square brackets, separating items

Possible Duplicate: When is a python object's hash computed and why is the hash of -1 different? Why do -1 and -2 both hash to the same number if Python? Since they do, how does Python tell these two numbers apart? >>> -1 is -2 False >>> hash(-1) is hash(-2) True >>> hash(-1) -2 >>> hash(-2) -2 andrew cooke -1 is a reserved value at the C level of CPython which prevents hash functions from being able to produce a hash value of -1 . As noted by DSM, the same is not true in IronPython and PyPy where hash(-1) != hash(-2) . See this Quora answer : If you write a type in a C extension module and

Is there a reasonably standard and cross platform way to print text (or even PS/PDF) to the system defined printer? Assuming CPython here, not something clever like using Jython and the Java printing API . Anuj Gupta Unfortunately, there is no standard way to print using Python on all platforms. So you'll need to write your own wrapper function to print. You need to detect the OS your program is running on, then: For Linux - import subprocess lpr = subprocess.Popen("/usr/bin/lpr", stdin=subprocess.PIPE) lpr.stdin.write(your_data_here) For Windows: http://timgolden.me.uk/python/win32_how_do_i