Tutorial by Examples: g

Mapping (`map`) and Reducing (`fold`) a Vector

Vectors can be map'd and fold'd,filter'd andzip`'d: Prelude Data.Vector> Data.Vector.map (^2) y fromList [0,1,4,9,16,25,36,49,64,81,100,121] :: Data.Vector.Vector Reduce to a single value: Prelude Data.Vector> Data.Vector.foldl (+) 0 y 66

Haskell Language • Vectors

Working on Multiple Vectors

Zip two arrays into an array of pairs: Prelude Data.Vector> Data.Vector.zip y y fromList [(0,0),(1,1),(2,2),(3,3),(4,4),(5,5),(6,6),(7,7),(8,8),(9,9),(10,10),(11,11)] :: Data.Vector.Vector

Haskell Language • Vectors

Filtering hashes

select returns a new hash with key-value pairs for which the block evaluates to true. { :a => 1, :b => 2, :c => 3 }.select { |k, v| k != :a && v.even? } # => { :b => 2 } When you will not need the key or value in a filter block, the convention is to use an _ in that place:...

Ruby Language • Hashes

Compile and sign schema

Cleaning and compiling code for iPhone, on project MyProject for schema Qa: xcrun xcodebuild clean \ -workspace "MyProject.xcworkspace" \ -scheme "YourScheme" \ -sdk iphoneos \ -configuration Debug \ archive \ -archivePath builds/MyProject.xcarchive...

Xcode • Command Line Tools

Memory management rules when using manual reference counting.

These rules apply only if you use manual reference counting! You own any object you create By calling a method whose name begins with alloc, new, copy or mutableCopy. For example: NSObject *object1 = [[NSObject alloc] init]; NSObject *object2 = [NSObject new]; NSObject *object3 = [object2 ...

Objective-C Language • Memory Management

Install packages

To install a new package, e.g. aeson: cabal install aeson

Haskell Language • Cabal

Working with sandboxes

A Haskell project can either use the system wide packages or use a sandbox. A sandbox is an isolated package database and can prevent dependency conflicts, e. g. if multiple Haskell projects use different versions of a package. To initialize a sandbox for a Haskell package go to its directory and r...

Haskell Language • Cabal

Managing Open Split Windows (Keyboard Shortcuts)

After you have opened a split window in vim (as demonstrated by many examples under this tag) then you will likely want to control windows quickly. Here is how to control split windows using keyboard shortcuts. Move to split Above/Below: Ctrl + w and k Ctrl + w and j Move to split Left/Right...

vim • Split windows

Sending HTML Email Using mail()

<?php $to = '[email protected]'; $subject = 'Sending an HTML email using mail() in PHP'; $message = '<html><body>This paragraph is bold.This text is italic.</body></html>'; $headers =...

PHP • Sending Email

Obtain class that satisfies generic parameter at runtime

Many unbound generic parameters, like those used in a static method, cannot be recovered at runtime (see Other Threads on Erasure). However there is a common strategy employed for accessing the type satisfying a generic parameter on a class at runtime. This allows for generic code that depends on ac...

Java Language • Generics

Denying access from IPs to files/directories

# Deny access to a directory from the IP 255.0.0.0 <Directory /path/to/directory> order allow,deny deny from 255.0.0.0 allow from all </Directory> # Deny access to a file from the IP 255.0.0.0 <FilesMatch "^\.ht"> order allow,deny deny fro...

Hypertext Access file • Denying Access

Finding information about a crash

When your app crashes, Xcode will enter the debugger and show you more information about the crash: The most important parts are: The red arrow The red arrow displays which line of code crashed & why it crashed. The debugger console Many crashes log more information to the debugger consol...

iOS • Debugging Crashes

Debugging SIGABRT and EXC_BAD_INSTRUCTION crashes

A SIGABRT or an EXC_BAD_INSTRUCTION usually means the app crashed itself intentionally because some check failed. These should log a message to the debugger console with more information; check there for more information. Many SIGABRTs are caused by uncaught Objective-C exceptions. There are a lo...

iOS • Debugging Crashes

Debugging EXC_BAD_ACCESS

EXC_BAD_ACCESS means the process tried to access memory in an invalid way, like dereferencing a NULL pointer or writing to read-only memory. This is the hardest kind of crash to debug, because it usually does not have an error message, and some crashes can be very difficult to reproduce and/or occu...

iOS • Debugging Crashes

Using different (local) Nuget package sources using UI

It is common for company to set up it's own nuget server for distribution of packages across different teams. Go to Solution Explorer and click Right Mouse button then choose Manage NuGet Packages for Solution In window that opens click on Settings Click on + in top right corner the...

.NET Framework • NuGet packaging system

A process committing suicide using kill()

A process can (try to) send a signal to any other process using the kill() function. To do so, the sending process needs to known the receiving process' PID. As, without introducing a race, a process can only be sure of its own PID (and the PIDs of its children) the most simple example to demonstra...

POSIX • Signals

Using SelectMany instead of nested loops

Given 2 lists var list1 = new List<string> { "a", "b", "c" }; var list2 = new List<string> { "1", "2", "3", "4" }; if you want to output all permutations you could use nested loops like var result = new List<s...

C# Language • LINQ Queries

Dependency Injection using Ninject

The following example shows how to set up Dependency Injection using Ninject as an IoC container. First add a CustomModule class to your WebJob project, and add any dependency bindings there. public class CustomModule : NinjectModule { public override void Load() { Bind<IMyI...

azure-webjobs • Azure Webjobs SDK

Generate time series of random numbers then down sample

import pandas as pd import numpy as np import matplotlib.pyplot as plt # I want 7 days of 24 hours with 60 minutes each periods = 7 * 24 * 60 tidx = pd.date_range('2016-07-01', periods=periods, freq='T') # ^ ^ # | ...

pandas • Grouping Time Series Data

Locking modules to specific versions

By default, npm installs the latest available version of modules according to each dependencies' semantic version. This can be problematic if a module author doesn't adhere to semver and introduces breaking changes in a module update, for example. To lock down each dependencies' version (and the ve...

Node.js • npm