函数式编程在工业界的应用日趋广泛。Scala作为众多应用使用的主要语言大力推进了这一趋势。Scala融合了函数式编程和面向对象编程的有点，可以和Java以及JavaScript无缝衔接。很多重量级的应用框架像Apache Spark,Kafka以及Akka都是使用Scala实现的。而这些应用框架正是很多网站的核心基础框架，像Twitter，Tumblr 和Coursera。 这门课程会带你认识函数式编程风格，以及如何把这种风格应用于日常的生产开发中。通过探索函数编程中广泛存在的不可变元素，追踪程序运行过程中函数标记的变化，你也会对函数式编程的原理有深刻认识。 这门课程注重实践，课程中的大部分单元都会使用一些简短的程序来阐述基本原理和概念，听众可以试着运行这些程序并尝试改写它们。这门课程附带有一些列的编程项目作为家庭作业。 学习目标，完成这门课程的学习后，你会: -理解函数式编程的原理 -会使用递归，模式识别，高级函数 编写纯函数式程序 -会在函数式程序中使用对象和类 -会设计不可变的数据结构 -会分析函数的性质 -理解函数式编程的泛型类型 听众最好有以下背景：至少一年的编程经验，最好能熟练掌握Java或者C#，但是使用过其他语言像是 C/C++, Python, Javascript或者Ruby也足以上这门课。熟悉命令行编程。
Tools Setup for Linux
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来自 École Polytechnique Fédérale de Lausanne 的课程
Scala 函数式程序设计原理
5292 个评分
École Polytechnique Fédérale de Lausanne
5292 个评分
课程 1（共 5 门，Specialization Functional Programming in Scala）
从本节课中
Getting Started + Functions & Evaluation
Get up and running with Scala on your computer. Complete an example assignment to familiarize yourself with our unique way of submitting assignments. In this week, we'll learn the difference between functional imperative programming. We step through the basics of Scala; covering expressions, evaluation, conditionals, functions, and recursion
与讲师见面
Martin OderskyProfessor
Computer Science
System, so
the cutting of the section in the video lectures part of the class website.
Everything that is shown on this video, is also explained in text and
tools of that page to the class website.
So, we are here, and we need to install a few things for our class.
The first one is the JDK, the Java development kit,
just a random environment in which Scala programs are executed.
This time the same as the [INAUDIBLE] which is strongly recommended to use this
version over Java 7 and 6.
The second one, this is SBT.
The main build tool for Scala which we'll use for building your programs and
submitting your assignments through Coursera.
Last but not least, we need an IDE that will help us to go within Scala.
In this case, we're going to show you how to install.
There are other options, though, you can also use the Scala IDE and sign.
Well, let's get started by installing JDK.
Here there are three subsections for each operating system.
As we are in Ubuntu, let's go to the right section.
You have another Linux operating system.
You can check which comments are necessary to install Java either in this website or
in the official website offering the solution.
In this tutorial ,we're only going to cover Ubuntu deviant systems.
But, installing another system is pretty straightforward.
Usually, this is done with pseudo app get,
install, open JDK, 8JDK.
As we have already installed Java, we are going to skip this process.
But we're going to show you how this is done.
So we go to the terminal, and
we type pseudoapp.getinstall, open JDK8 JDK.
Type our password and we'll see that in that place.
And we have already installed this version.
In case you need to check if you have the right Java version,
you have to do java-version.
And you type in the terminal and you press OK, enter.
And you will see that the first line,
that version that you have is in here.
In this case, we have Java 8.
Let's install SBT, in order to install SBT, first, we need to unload it.
Installing SBT and we click this,
this link which will refer you to this website.
Actually, let's wait.
Cool.
So we go to this link.
And now we have the instructions to install SBT in any system.
So we go to the Linux link.
And we'll see here, the commands that we need to execute,
so that SBT is installed in our system.
The first ones, are creating a new repository, while,
having a new repository to the system.
And, update it, so that we can install SBT with this simple comment.
So, let's copy paste this comments.
We go to the Terminal and we paste them.
Once SBT is installed, let's check that we have the right version of SBT.
For that, we need to type SBT about.
This is usually going to take some time on the first time you execute it because SBT
has to bootstrap itself.
As you see here, we do have the right version, 0.13.11.
As a side note, SBT versions, are backwards compatible with previous
versions of SBT, but not the other way around.
That's good to know, when we use SBT in our daily workflow.
So, now it's saying it's intalling IntelliJ IDEA.
For that, we need to go back to the tutorial, and
we also go here, in this thing, to install this idea tutorial.
So,
First, we need to download Intellij IDEA.
For that, we need to get to the official website and
make sure that we are in the Linux option.
And we download the IntelliJ IDEA.
As we have already done this, we just need to go to the, Downloads folder.
Oops, here, yeah.
And we'll see that we have the compressed file that we have just downloaded and
the file or the folder that is the result of decompressing this file.
So usually you can just decompress this file with x + v + F6.
And we're going to do it again.
Cool.
So we have the folder here.
Right?
And what we need to do is to go in, and we'll see that we have several folders.
Bin, lib, plugins, etc.
So what we need to do is to go to the binary folder, and
we need to execute the script that's going to execute IntelliJ IDEA.
That's
called
Idea.sh.
The next step to install Esker plugin so
the IntelliJ recognizes both SBT and Esker 5, so
we go to configure And now we'll go to plugs ins here.
And now we have to go here and install the plug in, and type.
Usually, there is a green button here that says install.
As we have already installed this car plugin, we don't need to do this.
But you will, so the following steps for you will be
to install escala and then restart [INAUDIBLE].
So we're going to close this, and
now we're going to create a new project.
In this window we have to make sure that we select this color and SBT.
So, we're going to extend.
Now we need to name our new project so let's name it "Sample".
Let's make sure that we have the right versions.
One eight here and zero thirteen and two eleven eight for SPTS color version.
If you don't have anything here we need to go to type new and
[INAUDIBLE] will automatically detect your [INAUDIBLE] the case, so
just have to press okay and that's it.
So we finish.
With [INAUDIBLE].
And now [INAUDIBLE] is going to create the project.
And it's going to select everything, so that we can start coding.
Close this.
Now SPT is executing.
So, it's going to create a new source folder here and
that's the one that we use for putting all our codes
Once we are ready let's play around with this [INAUDIBLE] worksheet.
This is a feature that gives you a very interactive console
to work with this color.
Now that we need to go to source and select main and
go straight to discard folder.
So, we just right click here and you
here When need to give it name say, Hello World.
And now we see that the format has changed, so
the idea is that we can type anything we want to here,
which is the [INAUDIBLE] command or [INAUDIBLE] I think only has Syntex.
Valid Syntex, right, and it's going to compile it and
it's going to show the result on the right.
So, let's create here an as a strength and we'll
see intelligent, well we press control S to save, then intellij is going to.
It's going to automatically compile this and
output results, which is going to be about
Cool.
So, now let's try to do something slightly more complicated, right?
So, let's go here and let's create a main application
in [INAUDIBLE] We need to write [INAUDIBLE] as well and
we're going to create [INAUDIBLE] class.
Our main application is going to be a [INAUDIBLE] here object and
we're going to decide the name.
This subject is going to be inside the package quote example, so
we're going to type example and then dots.
And then the name of our main application which is going to be
example with [INAUDIBLE].
So, we press OK and here we see the result,
but in order to allow [INAUDIBLE] compiler to run this main application,
we need to extend.
Application or
apps APP, extends, APP.
And now this is going to execute the body of this object,
so it's pooling here in a statement that
it's going to create hello world [SOUND].
As you see, [INAUDIBLE] has recognized this as the main application, and
there is a small icon here that we can click.
And we see that we have several options.
The first one is run example, second one there is [INAUDIBLE] sample, and
the third one is run example quick coverage.
Here we're going to just run the example.
And if everything goes well we're going to figure out the bottom part of the
Call, so it has compiled.
Now it's executing the program, and we see the output here.
So let's go back to the tutorial.
I'll see where we are.
We're in the step seven, and now we're going to learn how to open an SBT project.
We come back, we're going to close the project and
we're going to import it.
By taking Q and input products.
So, import a product A it goes here
and we see that [INAUDIBLE] And in the project folder which is the project.
So we select a built file and we click ok.
And now, we see this window.
And this window you can set up information about your project and
specifically we see that we can set up the JAVA version, which is the correct one.
One eight, and other options that we will explain later on.
So we click there, and now SVT is going to create a new SVT project.
But it's going to re-use the SVT project that we already created, but
it has to protect the source files and also, which folders are in this project.
We see the recognized folders.
We continue.
Now what we're going to do is change the beauty file.
We find the beauty file here and we click on it.
We can add a new dependency called scholar test as you see there
is a notification here and this notification with three options.
The first one is,
reference project, the second one is enable IT port the other is to ignore.
Enable and deport is official we will refresh SBT every time we change
a file An SPT file or a SPT folder,
this is extremely useful and I recommend to enable it.
So we are going to enable it here, and we are going to add a dependency.
So we are going to go back to the tutorial
And copy, paste this command here, the second one.
We'll save
the file with
control-S.
And has automatically SVT.
And now we are waiting for the result of SVT and the JSON error.
Just a warning.
Close and now [INAUDIBLE] is going to index the new
appendices we just added to the project.
Which is cool.
It means that everything went fine.
Now we want to execute any [INAUDIBLE] comment, we press alt 12
And these are going to open a terminal in our project folder with the example.
Now we are able to execute this here.
Remember that if you do this in another project folder, it's not going to work.
It has to be in the work project folder.
And we can type now nsbt Commands.
So let's compare again the project.
So that's it, now you're ready to use this current assignment.
Good luck.
