scala常用语法之控制结构
2016-09-19 16:32
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[b]字符串内插,并格式化数值[/b]
[code=scala;toolbar:false">scala> val name = "Jerry"
name: String = Jerry
scala> val info = s"My name is $name." // 字符串内插
info: String = My name is Jerry.
scala> val a = 2.7255
a: Double = 2.7255
scala> printf(f"You are $a%.2f.") // 格式化数值,字符串内插
You are 2.73.
正则表达式scala> val input = "Frank,123 Main,925-555-1943,95122"
res90: String = Frank,123 Main,925-555-1943,95122
scala> val pattern = """([\d]{3}-){2}[\d]{4}""".r // 正则表达式
pattern: scala.util.matching.Regex = ([\d]{3}-){2}[\d]{4}
scala> pattern.findAllIn(input).toList // 匹配正则表达式
res94: List[String] = List(925-555-1943)
条件表达式val s = if (n > 0) 1 else -1 // 可以将if/else的值赋给变量
println(s)
val x = if ( n > 0) "postive" else -1 // 两个分支类型的公共超类为Any
println(x)
val u = if ( n > 0) 1 else () // 每个表达式都应该有某种值 if ( n > 0) 1 等价于 if ( n > 0) 1 else ()
println(u)
循环
[code=scala;toolbar:false">scala> val name = "Jerry"
name: String = Jerry
scala> val info = s"My name is $name." // 字符串内插
info: String = My name is Jerry.
scala> val a = 2.7255
a: Double = 2.7255
scala> printf(f"You are $a%.2f.") // 格式化数值,字符串内插
You are 2.73.
正则表达式scala> val input = "Frank,123 Main,925-555-1943,95122"
res90: String = Frank,123 Main,925-555-1943,95122
scala> val pattern = """([\d]{3}-){2}[\d]{4}""".r // 正则表达式
pattern: scala.util.matching.Regex = ([\d]{3}-){2}[\d]{4}
scala> pattern.findAllIn(input).toList // 匹配正则表达式
res94: List[String] = List(925-555-1943)
条件表达式val s = if (n > 0) 1 else -1 // 可以将if/else的值赋给变量
println(s)
val x = if ( n > 0) "postive" else -1 // 两个分支类型的公共超类为Any
println(x)
val u = if ( n > 0) 1 else () // 每个表达式都应该有某种值 if ( n > 0) 1 等价于 if ( n > 0) 1 else ()
println(u)
循环
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