What is string? String is an ordered collection of characters. Like NSString in objective C we have String type in swift and for characters we have character type. String is a combination of characters.
You can create string as
var myName = “iPhone Development”
To initialize an empty string
var myName = ” ”
var initializemyName = String()
Here myName and initializemyName are both empty string and the only difference between them is that myName is literal string and the second line is a syntax to initialize a string in swift.
Strings can be mutated in swift as we are doing in objective C.
var myName = ”iPhone”
myName += “Development”
Now the output of myName would be
println(“output of myName= (myname)”)
It will print output of myName= iPhone Development
String declare as variable or var can be mutated and string declared as constant or let are immutable strings. The below code will throw error at compile time that a constant string cannot be modified
let myName = ”iPhone”
myName += “Development”
You can check for empty string by using isEmpty property of a string, this will return a Boolean value to you
var emptyString = “”
if emptyString.isEmpty
{
println(“String is empty”)
}
Compare Strings:
Swift provide three ways to compare string
- string equality
- prefix equality
- suffix equality
var firstString = “We are same”
var secondString = “We are same”
if firstString = secondString
{
println(“Both strings are same”)
}
To check prefix we can use
if firstString.hasPrefix(“We”)
{
println(“First string contains we”)
}
To check suffix we can use
if secondString.hasSuffix(“same”)
{
println(“Second string contains same”)
}
UPPERCASE and lowercase :
We can convert string to both in uppercase and lowercase by using property uppercaseString and lowercaseString
let string = ” normal”
let resultedString = string.uppercaseString
println(“result uppercase=(resultedString) )
resultedString = string.lowercaseString
println(“result lowercase=(resultedString) )