String
Introduction
The string in a String is a value type, and the value will be copied when passed, while the string passing of NSString is a reference. We can use for in to iterate over strings:
Copy the codeThe code is as follows:
var a : String = "a"
for c in "Hello" {
println(c)
}
The number of characters in a string can be calculated using countElements:
Copy the codeThe code is as follows:
countElements("1234567") // 7
However, it should be noted that the length of countElements and NSString are not always exactly the same value, because length uses UTF-16 values rather than Unicode characters. For example, after emoji is added, the UTF-16 calculates the result of 2, while the Unicode calculates the result of 1. You can see the following example:
Copy the codeThe code is as follows:
var a = "Hello
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