Tutorial by Examples: r

Python makes it very simple to check whether an item is in a list. Simply use the in operator. lst = ['test', 'twest', 'tweast', 'treast'] 'test' in lst # Out: True 'toast' in lst # Out: False Note: the in operator on sets is asymptotically faster than on lists. If you need to use it ...

To execute operations in a container, use the docker exec command. Sometimes this is called "entering the container" as all commands are executed inside the container. docker exec -it container_id bash or docker exec -it container_id /bin/sh And now you have a shell in your running...

To temporarily mark a file as ignored (pass file as parameter to alias) - type: unwatch = update-index --assume-unchanged To start tracking file again - type: watch = update-index --no-assume-unchanged To list all files that has been temporarily ignored - type: unwatched = "!git ls-fil...

There are two ways to achieve that, the first and most known is the following: docker attach --sig-proxy=false <container> This one literally attaches your bash to the container bash, meaning that if you have a running script, you will see the result. To detach, just type: Ctl-P Ctl-Q Bu...

Users of homebrew can install gradle by running brew install gradle

We plot a simple scatter plot using the builtin iris data set as follows: library(ggplot2) ggplot(iris, aes(x = Petal.Width, y = Petal.Length, color = Species)) + geom_point() This gives:

There are different cases where you must Explicitly specify the type parameters for a generic method. In both of the below cases, the compiler is not able to infer all of the type parameters from the specified method parameters. One case is when there are no parameters: public void SomeMethod<T...

To get all the information for a container you can run: docker inspect <container>

You can get an specific information from a container by running: docker inspect -f '<format>' <container> For instance, you can get the Network Settings by running: docker inspect -f '{{ .NetworkSettings }}' <container> You can also get just the IP address: docker inspect ...

Sometimes you need rewrite history with a rebase, but git push complains about doing so because you rewrote history. This can be solved with a git push --force, but consider git push --force-with-lease, indicating that you want the push to fail if the local remote-tracking branch differs from the b...

Sometimes, you need to work with an array while ensuring you don't modify the original. Instead of a clone method, arrays have a slice method that lets you perform a shallow copy of any part of an array. Keep in mind that this only clones the first level. This works well with primitive types, like n...

The job of the linker is to link together a bunch of object files (.o files) into a binary executable. The process of linking mainly involves resolving symbolic addresses to numerical addresses. The result of the link process is normally an executable program. During the link process, the linker wi...

Before the C compiler starts compiling a source code file, the file is processed in a preprocessing phase. This phase can be done by a separate program or be completely integrated in one executable. In any case, it is invoked automatically by the compiler before compilation proper begins. The prepro...

After the C pre-processor has included all the header files and expanded all macros, the compiler can compile the program. It does this by turning the C source code into an object code file, which is a file ending in .o which contains the binary version of the source code. Object code is not directl...

Sometimes it's necessary to convert a Discriminated Union to and from a string: module UnionConversion open Microsoft.FSharp.Reflection let toString (x: 'a) = match FSharpValue.GetUnionFields(x, typeof<'a>) with | case, _ -> case.Name let fromStri...

HTML <input type="range"></input> CSS EffectPseudo SelectorThumbinput[type=range]::-webkit-slider-thumb, input[type=range]::-moz-range-thumb, input[type=range]::-ms-thumbTrackinput[type=range]::-webkit-slider-runnable-track, input[type=range]::-moz-range-track, input[type=...

Given the text: foo: bar I would like to replace anything following "foo: " with "baz", but I want to keep "foo: ". This could be done with a capturing group like this: s/(foo: ).*/$1baz/ Which results in the text: foo: baz Example 1 or we could use \K,...

Software needed: Arduino IDE Setup Most Arduino-compatible boards have a USB port and come with a USB cable. Plug in the Arduino using the USB cable, and start up the Arduino IDE. Arduino IDE will start with a new sketch, typically with an emtpy setup() and loop() functions. This is enough to u...

Header file UIColor+XYZPalette.h: @interface UIColor (XYZPalette) +(UIColor *)xyz_indigoColor; @end and implementation UIColor+XYZPalette.m: @implementation UIColor (XYZPalette) +(UIColor *)xyz_indigoColor { return [UIColor colorWithRed:75/255.0f green:0/255.0f blue:130/255.0f al...

1. Install Node.js and NPM: Gulp requires Node.js and NPM, Node's package manager. Most installers include NPM with Node.js. Refer to the installation documentation or confirm it is already installed by running the following command in your terminal, npm -v // will return NPM version or error say...