Just a quick note here today on how to show methods from the String class in the Scala REPL, as well as methods from the StringOps class, which aren't seen as easily.
First, if you've used tab completion in the REPL, you may already know that you can show many Scala String class methods in the REPL. If you hit the [Tab] key once you'll see a short list of String methods:
scala> "foo".[Tab] + asInstanceOf charAt codePointAt codePointBefore codePointCount compareTo compareToIgnoreCase concat contains contentEquals endsWith equalsIgnoreCase getBytes getChars indexOf intern isEmpty isInstanceOf lastIndexOf length matches offsetByCodePoints regionMatches replace replaceAll replaceFirst split startsWith subSequence substring toCharArray toLowerCase toString toUpperCase trim
And then if you hit the [Tab] key a second time you'll see even more String class methods:
scala> "foo".[Tab][Tab] != ## $asInstanceOf $isInstanceOf + == asInstanceOf charAt codePointAt codePointBefore codePointCount compareTo compareToIgnoreCase concat contains contentEquals endsWith eq equals equalsIgnoreCase getBytes getChars getClass hashCode indexOf intern isEmpty isInstanceOf lastIndexOf length matches ne notify notifyAll offsetByCodePoints regionMatches replace replaceAll replaceFirst split startsWith subSequence substring synchronized this toCharArray toLowerCase toString toUpperCase trim wait
How to show StringOps methods in the REPL
You may be aware that the Scala String class appears to have many more methods, and these methods are made available to you through some implicit conversion magic. Those methods are actually in the StringOps class, and at the moment the only way I know to show those methods is like this:
scala> val s = new scala.collection.immutable.StringOps("s")
s: scala.collection.immutable.StringOps = s
scala> s.[Tab]
* ++ ++: +: /:
/:\ :+ :\ > >=
addString aggregate apply asInstanceOf canEqual
capitalize collect collectFirst combinations compare
compareTo contains containsSlice copyToArray copyToBuffer
corresponds count diff distinct drop
dropRight dropWhile elements endsWith equalsWith
exists filter filterNot find findIndexOf
findLastIndexOf first firstOption flatMap fold
foldLeft foldRight forall foreach format
formatLocal groupBy grouped hasDefiniteSize head
headOption indexOf indexOfSlice indexWhere indices
init inits intersect isDefinedAt isEmpty
isInstanceOf isTraversableAgain iterator last lastIndexOf
lastIndexOfSlice lastIndexWhere lastOption length lengthCompare
lines linesIterator linesWithSeparators map max
maxBy min minBy mkString nonEmpty
padTo par partition patch permutations
prefixLength product projection r reduce
reduceLeft reduceLeftOption reduceOption reduceRight reduceRightOption
replaceAllLiterally repr reverse reverseIterator reverseMap
reversedElements sameElements scan scanLeft scanRight
segmentLength seq size slice sliding
sortBy sortWith sorted span split
splitAt startsWith stringPrefix stripLineEnd stripMargin
stripPrefix stripSuffix sum tail tails
take takeRight takeWhile toArray toBoolean
toBuffer toByte toDouble toFloat toIndexedSeq
toInt toIterable toIterator toList toLong
toMap toSeq toSet toShort toStream
toString toTraversable union updated view
withFilter zip zipAll zipWithIndex
There are several drawbacks here, including the part where you have to remember what package the StringOps class is in so you can import it or invoke it as shown.
If you know of a better way to list these StringOps methods, I'd be very glad to hear about it. Just leave a note in the Comments section below.
books by alvin
 |
 |
 |
 |