What does %s mean in a python format string?

It is a string formatting syntax (which it borrows from C). Please see “PyFormat”: Python supports formatting values into strings. Although this can include very complicated expressions, the most basic usage is to insert values into a string with the %s placeholder. Edit: Here is a really simple example: The %s token allows me to insert (and potentially format) a string. … Read more

C++ Singleton design pattern

In 2008 I provided a C++98 implementation of the Singleton design pattern that is lazy-evaluated, guaranteed-destruction, not-technically-thread-safe:Can any one provide me a sample of Singleton in c++? Here is an updated C++11 implementation of the Singleton design pattern that is lazy-evaluated, correctly-destroyed, and thread-safe. See this article about when to use a singleton: (not often)Singleton: … Read more

Read file line by line using ifstream in C++

First, make an ifstream: The two standard methods are: Assume that every line consists of two numbers and read token by token: int a, b; while (infile >> a >> b) { // process pair (a,b) } Line-based parsing, using string streams: #include <sstream> #include <string> std::string line; while (std::getline(infile, line)) { std::istringstream iss(line); int … Read more

Echo equivalent in PowerShell for script testing

There are several ways: Write-Host: Write directly to the console, not included in function/cmdlet output. Allows foreground and background colour to be set. Write-Debug: Write directly to the console, if $DebugPreference set to Continue or Stop. Write-Verbose: Write directly to the console, if $VerbosePreference set to Continue or Stop. The latter is intended for extra … Read more

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