Scala Classroom (2): Foundation (i)

<p> <strong style= "color: #555555;" > Here we reprint <a style= "Font-weight:inherit; Font-style:inherit; Color: #0085cf; " >twitter's Scala classroom </a> , reproduced in the basic content of the Twitter-based Scala classroom Chinese translation, some small changes .</strong></p><p> < strong> expression </strong></p><pre class= "Brush:scala; Title:; Notranslate "title=" ">scala> 1 + 1res0:int = 2</pre><p> Res0 is the variable name automatically created by the interpreter, used to refer to the computed result of the expression. It is of type int with a value of 2. </p><p> Scala (almost) everything is an expression. </p><p> <strong> values </strong><br/> You can give the result of an expression a name that is assigned to a non-variable (val). </p><pre class= "Brush:scala; Title:; Notranslate "title=" ">scala> val 1 + 1two:int = 2</pre><p> <strong> variable </strong>&lt ;br/> If you need to modify the binding of this name and result, you can choose to use Var</p><pre class= "Brush:scala; Title:; Notranslate "title=" ">scala> var name =" Steve "name:string = stevescala> name =" Marius "name:string = marius& lt;/pre><p> <strong> function </stronG><br/> You can create a function using def. </p><pre class= "Brush:scala; Title:; Notranslate "Title=" ">scala> def AddOne (m:int): Int = m + 1addOne: (m:int) int</pre><p> in Scala, you need to The function parameter specifies the type signature. </p><pre class= "Brush:scala; Title:; Notranslate "title=" ">scala> val three = AddOne (2) Three:int = 3</pre><p> If the function has no arguments, you can not write parentheses. </p><pre class= "Brush:scala; Title:;  Notranslate "Title=" ">scala> def three () = 1 + 2three: () intscala> three () Res0:int = 3scala> Threeres2:int = 3</pre><p> <strong> Anonymous functions </strong><br/> You can create anonymous functions. </p><pre class= "Brush:scala; Title:; Notranslate "title=" ">scala> (X:int) + x + 1res3:int = Int = <function1></pre><p> this letter The number is an int variable named x plus 1. </p><pre class= "Brush:scala; Title:; Notranslate "title=" ">scala> res3 (1) res4:int = 2</pre><p> You can pass anonymous functions or save them as invariants. </p><pre class= "Brush:scala; Title:; Notranslate "title=" ">scala> val addone = (x:int) + x + 1addone:int = Int = <function1>scala> A Ddone (1) res5:int = 2</pre><p> If your function has many expressions, you can use {} to format the code to make it easy to read. </p><pre class= "Brush:scala; Title:; Notranslate "title=" ">def Timestwo (i:int): Int = {println (" Hello World ") I * 2}</pre><p> for anonymous functions and so on. Lt;/p><pre class= "Brush:scala; Title:;   Notranslate "title=" >scala> {i:int = |   println ("Hello World") | I * 2 | }res6:int = = <function1></pre><p> When an anonymous function is passed as a parameter, this syntax is often used in </p>

　　

Scala Classroom (2): Foundation (i)