View Category
Strings
Printing

Output a string to the console

Write the string "Hello World!" to STDOUT
scala
println("Hello World!")
printf("Hello World!\n")

Retrieve a string containing ampersands from the variables in a url

My PHP script first does a query to obtain customer info for a form. The form has first name and last name fields among others. The customer has put entries such as "Ron & Jean" in the first name field in the database. Then the edit form script is called with variables such as

"http://myserver.com/custinfo/edit.php?mode=view&fname=Ron & Jean&lname=Smith".

The script variable for first name $_REQUEST['firstname'] never gets beyond the "Ron" value because of the ampersand in the data.

I have tried various functions like urldecode but all to no avail. I even tried encoding the url before the view screen is painted so that the url looks like "http://myserver/custinfo/edit.php?mode=view&fname="Ronxxnbsp;xxamp;xxnbsp;Jean"&lname=SMITH". (sorry I had to add the xx to replace the ampersand or it didn't display meaningful url contents the browser sees.)

Of course this fails for the same reasons. What is a better approach?
scala
import java.net.URLEncoder

val params = Map("mode"->"view", "fname"->"Ron & Jean", "lname"->"Smith")
var url = ""

for ((k, v) <- params) { url += URLEncoder.encode(k) + "=" + URLEncoder.encode(v) }

println(url)
import java.net.URLEncoder
val params = Map("mode"->"view", "fname"->"Ron & Jean", "lname"->"Smith")
(for ((k, v) <- params) yield URLEncoder.encode(k) + "=" + URLEncoder.encode(v) ).mkString("&")

string-wrap

Wrap the string "The quick brown fox jumps over the lazy dog. " repeated ten times to a max width of 78 chars, starting each line with "> "

Expected output:
> The quick brown fox jumps over the lazy dog. The quick brown fox jumps over t
> he lazy dog. The quick brown fox jumps over the lazy dog. The quick brown fox
> jumps over the lazy dog. The quick brown fox jumps over the lazy dog. The qui
> ck brown fox jumps over the lazy dog. The quick brown fox jumps over the lazy
> dog. The quick brown fox jumps over the lazy dog. The quick brown fox jumps o
> ver the lazy dog. The quick brown fox jumps over the lazy dog.
scala
object Wrap {
def wordWrap(str: String, width: Int, lineStart: String, reps: Int) = {
var strRepeated = ""
for(i <- 0 until reps) strRepeated += str
while(strRepeated.length > width) {
println(lineStart + strRepeated.substring(0, (width-1)))
strRepeated = strRepeated.substring(width)
}
println(lineStart + strRepeated)
}

def main(args: Array[String]) = {
wordWrap("The quick brown fox jumps over the lazy dog. ", 78, "> ", 10)
}
}
def stringWrap(s: String): List[String] =
if (s.length == 0) Nil else s.take(78) :: stringWrap(s.drop(78))

stringWrap("The quick brown fox jumps over the lazy dog. " * 10).foreach(line => println("> " + line))
("The quick brown fox jumps over the lazy dog. " * 10) grouped(78) foreach { line => println("> " + line) }
Declaration

Define a string containing special characters

Define the literal string "\#{'}${"}/"
scala
val special = "\\#{'}${\"}/"
val special2 = """\#{'}${"}/"""

Define a multiline string

Define the string:
"This
Is
A
Multiline
String"
scala
val text = """This
Is
A
Multiline
String"""
val text = "This\nIs\nA\nMultiline\nString"

Define a string containing variables and expressions

Given variables a=3 and b=4 output "3+4=7"
scala
printf("%d+%d=%d\n", a, b, a + b)
"%d+%d=%d".format(a, b, a + b)
s"$a + $b = ${a+b}"
Manipulation

Reverse the characters in a string

Given the string "reverse me", produce the string "em esrever"
scala
val reversed = "reverse me".reverse

Reverse the words in a string

Given the string "This is a end, my only friend!", produce the string "friend! only my end, the is This"
scala
"This is the end, my only friend!".split(" ").reverse.reduceLeft( (x,y) => x+' '+y )
val reversed = revwords("This is the end, my only friend!")
(("This is the end, my only friend!" split " ") reverse) mkString " "
val reversedText = text.split(" ").reverse.mkString(" ")

Text wrapping

Wrap the string "The quick brown fox jumps over the lazy dog. " repeated ten times to a max width of 78 chars, starting each line with "> ", yielding this result:

> The quick brown fox jumps over the lazy dog. The quick brown fox jumps
> over the lazy dog. The quick brown fox jumps over the lazy dog. The
> quick brown fox jumps over the lazy dog. The quick brown fox jumps
> over the lazy dog. The quick brown fox jumps over the lazy dog. The
> quick brown fox jumps over the lazy dog. The quick brown fox jumps
> over the lazy dog. The quick brown fox jumps over the lazy dog. The
> quick brown fox jumps over the lazy dog.
scala
val prefix = "> " ; val input = "The quick brown fox jumps over the lazy dog."

WordUtils.wrap(input * 10, 72 - prefix.length).split("\n") foreach {(x) => printf("%s%s\n", prefix, x)}
def wrap(words: List[String]): List[List[String]] = words match {
case Nil => Nil
case _ =>
val output = (words.inits.dropWhile { _.mkString(" ").length > 78 }) next;
output :: wrap(words.drop(output.length))
}

wrap(("The quick brown fox jumps over the lazy dog. " * 10) split(" ") toList) foreach {
words => println("> " + words.mkString(" "))
}

Remove leading and trailing whitespace from a string

Given the string "  hello    " return the string "hello".
scala
val s = " hello ".trim

Simple substitution cipher

Take a string and return the ROT13 and ROT47 (Check Wikipedia) version of the string.
For example:
String is: Hello World #123
ROT13 returns: Uryyb Jbeyq #123
ROT47 returns: w6==@ (@C=5 R`ab
scala
val uppers = 'A' to 'Z'
val lowers = 'a' to 'z'

val alpha13 = (uppers ++ lowers).mkString
val beta13 = ((uppers drop 13) ++ (uppers take 13) ++ (lowers drop 13) ++ (lowers take 13)).mkString

val alpha47 = """!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~"""
val beta47 = """PQRSTUVWXYZ[\]^_`abcdefghijklmnopqrstuvwxyz{|}~!"#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNO"""

// generic translation function
def rot (alpha: String, beta: String)(c: Char) = if (alpha contains c) beta(alpha indexOf c) else c

// specific translation functions curried with the respective alphabets
val rot13 = rot(alpha13, beta13) _
val rot47 = rot(alpha47, beta47) _

assert(("Hello World #123" map rot13).toString == "Uryyb Jbeyq #123")
assert(("Hello World #123" map rot47).toString == "w6==@ (@C=5 R`ab")
Case

Make a string uppercase

Transform "Space Monkey" into "SPACE MONKEY"
scala
println("Space Monkey".toUpperCase)

Make a string lowercase

Transform "Caps ARE overRated" into "caps are overrated"
scala
"Caps ARE overRated".toLowerCase

Capitalise the first letter of each word

Transform "man OF stEEL" into "Man Of Steel"
scala
def capitalize(s: String) = { s(0).toUpperCase + s.substring(1, s.length).toLowerCase }

"man OF stEEL".split("\\s") foreach {(x) => text.append(capitalize(x)).append(" ")}
val text = WordUtils.capitalizeFully("man OF stEEL")
val text = StringUtils.join("man OF stEEL".split("\\s") map {(x) => StringUtils.capitalize(x.toLowerCase) + " "})
// can be solved without external libraries
(("man OF stEEL" toLowerCase) split " " map (_ capitalize)).mkString(" ")
// This is just a slightly more compact form of the previous solution (my fav).
// It would be nice if split defaulted to whitespace (precompiled reg ex).
"man OF stEEL".toLowerCase.split(" ").map(_.capitalize) mkString " "