Tutorial by Examples: df

Sometimes it happens that a file was being tracked by git, but in a later point in time was added to .gitignore, in order to stop tracking it. It's a very common scenario to forget to clean up such files before its addition to .gitignore. In this case, the old file will still be hanging around in th...

Normally, to remove files that are staged to be committed using the git reset commit, reset has a lot of functions depending on the arguments provided to it. To completely unstage all files staged, we can make use of git aliases to create a new alias that uses reset but now we do not need to remembe...

There are some functions to help tear down Free computations by interpreting them into another monad m: iterM :: (Functor f, Monad m) => (f (m a) -> m a) -> (Free f a -> m a) and foldFree :: Monad m => (forall x. f x -> m x) -> (Free f a -> m a). What are they doing? First l...

#!/bin/bash FILENAME="/etc/passwd" while IFS=: read -r username password userid groupid comment homedir cmdshell do echo "$username, $userid, $comment $homedir" done < $FILENAME In unix password file, user information is stored line by line, each line consisting of i...

In Object Oriented Programming a common task is to compose objects (values). In Functional Programming it is as common task to compose values as well as functions. We are used to compose values from our experience of other programming languages using operators like +, -, *, / and so on. Value co...

Immediately invoked function expressions can be used to create a private scope while producing a public API. var Module = (function() { var privateData = 1; return { getPrivateData: function() { return privateData; } }; })(); Module.getPrivateData(); // 1 Module.priva...

Suppose you have a parentView into which you want to insert a new subView programmatically (eg. when you want to insert an UIImageView into a UIViewController's view), than you can do it as below. Objective-C [parentView addSubview:subView]; Swift parentView.addSubview(subView) You can also...

To get the the exact size of a UIButton's text based on its font, use the function intrinsicContentSize. Swift button.intrinsicContentSize.width Objective-C button.intrinsicContentSize.width;

NSString provides method boundingRectWithSize which can be used to predict the resulting CGSize of a UILabel based on its text and font without the need of creating a UILabel Objective-C [[text boundingRectWithSize:maxSize options:(NSStringDrawingTruncatesLastVisibleLine | NSStringDrawingUsesLineF...

User-defined functionals Users can create their own functionals to varying degrees of complexity. The following examples are from Functionals by Hadley Wickham: randomise <- function(f) f(runif(1e3)) lapply2 <- function(x, f, ...) { out <- vector("list", length(x...

I won't explain what Any and FirstOrDefault does because there are already two good example about them. See Any and First, FirstOrDefault, Last, LastOrDefault, Single, and SingleOrDefault for more information. A pattern I often see in code which should be avoided is if (myEnumerable.Any(t=>t.Fo...

Things you need A paid Apple Developer Program Membership A valid App ID and identifier for you app (like com.example.MyApp) which is not used before anywhere Access to developer.apple.com and Member Center An iOS Device to test (as Push Notifications don't work on Simulator) Enabling t...

To list files and folders inside current directory, we use ls command: user@host:/$ ls bin boot cdrom dev etc home initrd.img lib lib64 lost+found media mnt opt proc root run sbin srv sys tmp usr var vmlinuz ls prints folder structure in simple view, color coded by type....

The most important consequence of the One Definition Rule is that non-inline functions with external linkage should only be defined once in a program, although they can be declared multiple times. Therefore, such functions should not be defined in headers, since a header can be included multiple tim...

A function template can be overloaded under the rules for non-template function overloading (same name, but different parameter types) and in addition to that, the overloading is valid if The return type is different, or The template parameter list is different, except for the naming of paramete...

In this question, @Viclib asked about using rewrite rules to exploit typeclass laws to eliminate some overloaded function calls: Mind the following class: class ListIsomorphic l where toList :: l a -> [a] fromList :: [a] -> l a I also demand that toList . fromList == id. H...

Makes a request only sending part of the form. The text1 value is set, but not text2, as the listener states. Bean.java @ManagedBean @ViewScoped public class Bean { private String text1; private String text2; public String getText1() { return text1; } pu...

Some devices connected through a serial port send data to your program at a constant rate (streaming data) or send data at unpredictable intervals. You can configure the serial port to execute a function automatically to handle data whenever it arrives. This is called the "callback function&quo...

#include <Servo.h> Servo srv; void setup() { srv.attach(9); // Attach to the servo on pin 9 } To use a servo, you need to call attach() function first. It starts generating a PWM signal controlling a servo on a specified pin. On boards other than Arduino Mega, use of Servo lib...

Here is a workaround to temporary reset your password for your account. Login to your hosting panel and use the database tool that is available (probably PHPmyAdmin). Load the appropriate database and then go to the jos_users table. (The database prefix might be different for your case). ...