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Is there a Python equivalent of the C# null-coalescing operator?
In C# there's a null-coalescing operator (written as ?? ) that allows for easy (short) null checking during assignment:
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What is a good pattern for using a Global Mutex in C#?
...id );
// Need a place to store a return value in Mutex() constructor call
bool createdNew;
// edited by Jeremy Wiebe to add example of setting up security for multi-user usage
// edited by 'Marc' to work also on localized systems (don't use just "Everyone")
var allowEveryoneRu...
How to parse/read a YAML file into a Python object? [duplicate]
...ame: Node 2
branch2-1:
name: Node 2-1
And you've installed PyYAML like this:
pip install PyYAML
And the Python code looks like this:
import yaml
with open('tree.yaml') as f:
# use safe_load instead load
dataMap = yaml.safe_load(f)
The variable dataMap now contains...
What is the size of an enum in C?
...set of enum values, but I need each enum value to be 64 bits wide. If I recall correctly, an enum is generally the same size as an int; but I thought I read somewhere that (at least in GCC) the compiler can make the enum any width they need to be to hold their values. So, is it possible to have an e...
import module from string variable
...
Finally, also remember that you can't import anything if there is no __init__.py in the folder with file you are trying to import.
– Seanny123
Dec 6 '13 at 7:31
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Why does Windows64 use a different calling convention from all other OSes on x86-64?
AMD has an ABI specification that describes the calling convention to use on x86-64. All OSes follow it, except for Windows which has it's own x86-64 calling convention. Why?
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What is the best regular expression to check if a string is a valid URL?
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I wrote my URL (actually IRI, internationalized) pattern to comply with RFC 3987 (http://www.faqs.org/rfcs/rfc3987.html). These are in PCRE syntax.
For absolute IRIs (internationalized):
/^[a-z](?:[-a-z0-9\+\.])*:(?:\/\/(?:(?:%[0-9a-f][0-9a-f]...
Union of dict objects in Python [duplicate]
...yptic, and it immediately makes most readers balk and the remainder assume all the keys in x would have to be legal parameter names. IMHO, the fact it works is a bug in the name-checking mechanisms in the implementation. What happens when you rely on bugs? They either get fixed, or become politic...
App Inventor 2 UDP网络通信教程 - 发送和接收UDP数据包 · App Inventor 2 中文网
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if (contains_text(message, "DEVICE:")) {
var 设备名称 = replace_all(message, "DEVICE:", "")
var 设备信息 = join(设备名称, " (", senderAddress, ")")
if (not(is_in_list(设备信息, foundDevices))) {
add_items_to_list(foundDevices, 设备信息)
ListView_De...
Is there a difference between “==” and “is”?
... a
True
In your case, the second test only works because Python caches small integer objects, which is an implementation detail. For larger integers, this does not work:
>>> 1000 is 10**3
False
>>> 1000 == 10**3
True
The same holds true for string literals:
>>> "a" i...