Convert java.lang.String to Scala string

Question

I have a String in my Scala program that I'd like to cast as an Int.

def foo(): Int = x.getTheNumericString().toInt

The problem is that x.getTheNumericString() comes from a Java library and returns a java.lang.String, which doesn't have a toInt method.

I know I can create a Scala string with val s: String = "123", but I noticed that when I create a string like val t = "456" I get a java.lang.String. I have heard that Scala String is just a wrapper around java.lang.String, but I haven't found any clear documentation on how to cast to the Scala string.

Is there some function I can use like:

def foo(): Int = f(x.getTheNumericString()).toInt

As it stands now, my compiler complains about the original definition value toInt is not a member of String

om-nom-nom · Accepted Answer · 2014-05-22 14:58:45Z

11

It's not a wrapper, but actually java.lang.String. No need in additional hassle:

» touch 123
» scala
...

val foo = new java.io.File("123")
// java.io.File = 123

// Get name is a java api, which returns Java string

foo.getName.toInt
// res2: Int = 123

answered May 22, 2014 at 14:58

om-nom-nom

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11 Comments

gpampara Over a year ago

To back this up, check the source of Predef out: github.com/scala/scala/blob/v2.11.1/src/library/scala/…

om-nom-nom Over a year ago

@gpampara this will require an additional comment, stating that type will be substituted at compile time and leaves no actual traces in resulting bytecode

munk Over a year ago

I wish that were true, but my compiler complains that toInt is not a member of String

om-nom-nom Over a year ago

@usmcs which version of Scala are you using?

munk Over a year ago

2.10.1 in Intellij 13.0.1

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Erik Kaplun · Accepted Answer · 2014-05-22 15:07:04Z

4

java.lang.String is implicitly amended with Scala specific string methods so no manual conversion should be necessary.

answered May 22, 2014 at 15:07

Erik Kaplun

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Comments

Sameer · Accepted Answer · 2019-10-15 17:50:32Z

0

Use asInstanceOf[String] to syntactically convert Java string to Scala string.

val str: String = "java_string".asInstanceOf[String]

edited Oct 15, 2019 at 17:50

answered Oct 15, 2019 at 17:41

Sameer

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