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Resolve build errors due to circular dependency amongst classes
...riting a compiler. And you see code like this.
// file: A.h
class A {
B _b;
};
// file: B.h
class B {
A _a;
};
// file main.cc
#include "A.h"
#include "B.h"
int main(...) {
A a;
}
When you are compiling the .cc file (remember that the .cc and not the .h is the unit of compilation), you ne...
Delete column from pandas DataFrame
...
As you've guessed, the right syntax is
del df['column_name']
It's difficult to make del df.column_name work simply as the result of syntactic limitations in Python. del df[name] gets translated to df.__delitem__(name) under the covers by Python.
...
Best way to do multiple constructors in PHP
You can't put two __construct functions with unique argument signatures in a PHP class. I'd like to do this:
21 Answers
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How to uninstall the “Microsoft Advertising SDK” Visual Studio extension?
...
Run the following from an elevated Powershell prompt:
gwmi Win32_Product -Filter "Name LIKE 'Microsoft Advertising%'"
And it should show the culprits:
IdentifyingNumber : {6AB13C21-C3EC-46E1-8009-6FD5EBEE515B}
Name : Microsoft Advertising SDK for Windows 8.1 - ENU
Vendor ...
How to remove illegal characters from path and filenames?
...blic string ReplaceInvalidChars(string filename)
{
return string.Join("_", filename.Split(Path.GetInvalidFileNameChars()));
}
This answer was on another thread by Ceres, I really like it neat and simple.
share
...
How are Python's Built In Dictionaries Implemented?
...keys' hashes. You can think of it like this:
hash key dict_0 dict_1 dict_2...
...010001 ffeb678c 633241c4 fffad420 ...
... ... ... ... ...
For a 64 bit machine, this could save up to 16 bytes per key per extra dictionary.
Shared Keys for...
error LNK2019: unresolved external symbol _WinMain@16 referenced in function ___tmainCRTStartup
...you can just hint at what your entry point is, because you haven't defined ___tmainCRTStartup. You can do this by adding the following to Properties -> Linker -> Command line:
/ENTRY:"mainCRTStartup"
This way you get rid of the console window.
...
Behaviour of increment and decrement operators in Python
...so far as they don't explain what happens.
To be exact, +x evaluates to x.__pos__() and ++x to x.__pos__().__pos__().
I could imagine a VERY weird class structure (Children, don't do this at home!) like this:
class ValueKeeper(object):
def __init__(self, value): self.value = value
def __s...
Representing graphs (data structure) in Python
... both ways). We'll handle that by adding a directed parameter to the Graph.__init__ method. We'll also add some other helpful methods.
import pprint
from collections import defaultdict
class Graph(object):
""" Graph data structure, undirected by default. """
def __init__(self, connection...
滑动菜单使用指导 · App Inventor 2 中文网
...手：底部分享面板
拖一个按钮（改名 按钮_分享）和一个标签（改名 标签_结果）；
拖一个垂直布局（改名 垂直布局_面板，宽度设为充满，取消勾选「可见」），里面放三个按钮：
按钮_微信、按钮_朋友圈、按钮...