$ scala -help
Welcome to Scala 2.12.2 (Java HotSpot(TM) 64-Bit Server VM, Java 1.8.0_111).
Type in expressions for evaluation. Or try :help.
$ scala
scala>1+2 ?//scala支持自動推斷類型
res0:Int= 3
scala>1.5*2
res1:Double= 3.0
scala>3*res1
res2:Double= 9.0
scala>res2.to ? ? ? ? ? ? ?//scala有自動補全功能，tab鍵
to toChar toDouble toInt toRadians toString
toByte toDegrees toFloat toLong toShort
scala>res2.toInt
res4:Int= 9
scala>val result = 2 + 10 ? //val 定義變量不可變
result:Int= 12
scala>re
readBoolean ?readFloat readShort ?readf3 remote res2
readByte readInt readf ref require res4
readChar readLine readf1 refArrayOps res0result
readDouble readLong readf2 reflect res1
scala>result = 13 ? //不可變變量賦值報error
:12:error:reassignment to val
result = 13
scala>var name = "123"
name:String= 123
scala>val age :Int = 0
age:Int= 0
scala>val name: String = "lpfasd" ? //聲明時可限定類型
name:String= lpfasd
scala>val a,b,c=0 ? ? ?//可一行賦多數(shù)值
a:Int= 0
b:Int= 0
c:Int= 0
scala>0.to(5)? ? ? ? ? ? ? ? //Range代表的是一段整數(shù)的范圍
res6:scala.collection.immutable.Range.Inclusive= Range 0 to 5
scala>1.+(1) ? ? ? ? ? ? ?//數(shù)字也有方法
res7:Int= 2
scala>1++ ? ? ? ? ? ? ? ? ? ? ?//scala中去除了++，--。用+=，-=來替代
:12:error:value ++ is not a member of Int
1++
^
scala>age +=1
:13:error:value += is not a member of Int
Expression does not convert to assignment because receiver is not assignable.
age +=1
^
scala>import scala.math._ ? ?//導(dǎo)入文件
import scala.math._
scala>min(20,4) ? ? ?//比較大小
res10:Int= 4
scala>Array(1,2,3,4) ? //數(shù)組初始化
res11:Array[Int]= Array(1, 2, 3, 4)
scala>var array = Array(1,2,3,4) ?//自動識別類型
array:Array[Int]= Array(1, 2, 3, 4)
scala>array
res13:Array[Int]= Array(1, 2, 3, 4)
scala>array = Arr
ArrayArrayIndexOutOfBoundsExceptionArrowAssoc
ArrayCharSequenceArrayStoreException
scala>array = Array.apply(1,2,3,4)
array: Array[Int] = [I@71d3dfd5
scala>var array = Array.apply(1,2,3,4)
array:Array[Int]= Array(1, 2, 3, 4)
scala>var element = 100
element:Int= 100
scala>while(element>100){ ? ? ?//while循環(huán)
|println(element)
|element -= 2}
scala>while(element>10){
|println(element)
|element -= 2}
100
98
96
94
..... ? ? ? ? ? ?
12
scala>0 to element
res17:scala.collection.immutable.Range.Inclusive= Range 0 to 10
scala>for(i<-0 to element)println(i) ? //for??
0
1
2
3
……
scala>for(i<-0 to element if i%2 == 0)println(i) ? ? //帶過濾條件的查詢
0
2
4
6
8
10
//可變參數(shù)
scala>def sum(numbers:Int*) = {var result = 0;for(element<-numbers)result +=element;result} ?
sum:(numbers: Int*)Int
scala>sum(1,2,3,4,5,6,7,8,9)
res20:Int= 45
//引入io包
scala>import scala.io.Source._
?//讀取源文件（文件不存在，報異常）因是lazy，即不立即執(zhí)行，所以異常此時并未發(fā)生，調(diào)用時拋除
scala>lazy val content = fromFile("/root/asdasdasd")
content:scala.io.BufferedSource=
scala>fromFile("/root/asdasdasd")
java.io.FileNotFoundException: /root/asdasdasd (No such file or directory)
//存在編碼問題，應(yīng)注意解碼
scala>fromFile("/Users/name/Desktop/123.txt","utf-8")
java.nio.charset.MalformedInputException: Input length = 1
//本例對應(yīng)“GBK”
scala>fromFile("/Users/liupengfei/Desktop/123.txt","GBK").mkString
res28:String=
1.開源中國
網(wǎng)址https://git.oschina.net/peiphen/test
Git@OSC賬戶
賬號：
密碼：
…… ? ??
