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Length of generator output [duplicate]
...
The easiest way is probably just sum(1 for _ in gen) where gen is your generator.
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Multiple levels of 'collection.defaultdict' in Python
... @ScienceFriction Anything specific that you need help with? When d[new_key] is accessed, it will call the lambda which will create a new defaultdict(int). And when d[existing_key][new_key2] is accessed, a new int will be created.
– interjay
Oct 11 '13 at 1...
How can I create a copy of an object in Python?
... get a copy method (in 2, you'd use a slice to make a copy):
>>> a_list = list('abc')
>>> a_copy_of_a_list = a_list.copy()
>>> a_copy_of_a_list is a_list
False
>>> a_copy_of_a_list == a_list
True
Shallow Copies
Shallow copies are just copies of the outermost cont...
Creating C macro with ## and __LINE__ (token concatenation with positioning macro)
...PASTE2(x, y) TOKENPASTE(x, y)
#define UNIQUE static void TOKENPASTE2(Unique_, __LINE__)(void) {}
Then, __LINE__ gets expanded to the line number during the expansion of UNIQUE (since it's not involved with either # or ##), and then the token pasting happens during the expansion of TOKENPASTE.
It ...
Why is Python 3.x's super() magic?
...lf):
return super(Foo, self).baz() + 42
Spam = Foo
Foo = something_else()
Spam().baz() # liable to blow up
The same applies to using class decorators where the decorator returns a new object, which rebinds the class name:
@class_decorator_returning_new_class
class Foo(Bar):
def baz...
'is' versus try cast with null check
...ing)
{
var x = (string) o;
}
This translates to the following IL:
IL_0000: nop
IL_0001: ldstr "test"
IL_0006: stloc.0 // o
IL_0007: ldloc.0 // o
IL_0008: isinst System.String
IL_000D: ldnull
IL_000E: cgt.un
IL_0010: stloc.1
IL_0011: ldloc....
Performance difference for control structures 'for' and 'foreach' in C#
...ed
{
// Code size 49 (0x31)
.maxstack 1
.locals init (object V_0,
valuetype [mscorlib]System.Collections.Generic.List`1/Enumerator<object> V_1)
IL_0000: ldarg.0
IL_0001: callvirt instance valuetype [mscorlib]System.Collections.Generic.List`1/Enumerator<!0>...
What does multicore assembly language look like?
...els in the wild that boot from USB drives or "floppy" disks - here's an x86_32 version written in assembler using the old TSS descriptors that can actually run multi-threaded C code (github.com/duanev/oz-x86-32-asm-003) but there is no standard library support. Quite a bit more than you asked for b...
How do I get logs/details of ansible-playbook module executions?
...dd the following lines to your ansible configuration file:
[defaults]
log_path=/path/to/logfile
Ansible will look in several places for the config file:
ansible.cfg in the current directory where you ran ansible-playbook
~/.ansible.cfg
/etc/ansible/ansible.cfg
...
What is the difference between class and instance attributes?
...> a.foo.append(5)
>>> b.foo
[5]
>>> class A:
... def __init__(self): self.foo = []
>>> a, b = A(), A()
>>> a.foo.append(5)
>>> b.foo
[]
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