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Reverse a string in Python
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@Tanner [::-1] is fastest because it does not call any external functions, rather it's using slicing, which is highly-optimized in python. ''.join(list(reversed(s))) makes 3 function calls.
– hd1
Apr 27 at 13:51
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Python Pandas merge only certain columns
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You can use .loc to select the specific columns with all rows and then pull that. An example is below:
pandas.merge(dataframe1, dataframe2.iloc[:, [0:5]], how='left', on='key')
In this example, you are merging dataframe1 and dataframe2. You have chosen to do an outer left jo...
Python strftime - date without leading 0?
...omment until now. It turns out that datetime specifies a very interesting __format__ hook that allows you to write things like that.
– mgilson
Dec 4 '14 at 0:26
2
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How to call base.base.method()?
...Derived
{
public override void Say()
{
Console.WriteLine("Called from Special Derived.");
var ptr = typeof(Base).GetMethod("Say").MethodHandle.GetFunctionPointer();
var baseSay = (Action)Activator.CreateInstance(typeof(Action), this, ptr);
baseSay(...
Mimicking sets in JavaScript?
...the list is a little safer with this:
if (Object.prototype.hasOwnProperty.call(obj, A))
// put code here
}
because of potential conflict between built-in methods and/or properties on the base Object like the constructor property.
Sidebar on ES6: The current working version of ECMAScript 6 or s...
Callback functions in Java
... answered Nov 6 '14 at 10:02
Juh_Juh_
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Why does modern Perl avoid UTF-8 by default?
...?????????????????????
Set your PERL_UNICODE envariable to AS. This makes all Perl scripts decode @ARGV as UTF‑8 strings, and sets the encoding of all three of stdin, stdout, and stderr to UTF‑8. Both these are global effects, not lexical ones.
At the top of your source file (program, module, l...
How does “cat
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This is called heredoc format to provide a string into stdin. See https://en.wikipedia.org/wiki/Here_document#Unix_shells for more details.
From man bash:
Here Documents
This type of redirection instructs the shell to read...
mfc 按钮变成了非xp风格、界面变成windows经典样式？ - C++ UI - 清泛IT社...
...格 xp风格
stdafx.h中添加：
#ifdef _UNICODE
#if defined _M_IX86
#pragma comment(linker,"/manifestdependency:\"type='win32' name='Microsoft.Windows.Common-Controls' version='6.0.0.0' processorArchitecture='x86' publicKeyToken='6595b64144ccf1df' langu...
Import SQL file into mysql
I have a database called nitm . I haven't created any tables there. But I have a SQL file which contains all the necessary data for the database. The file is nitm.sql which is in C:\ drive . This file has size of about 103 MB. I am using wamp server.
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