Question

How does Actionscript handle the following substrings? For the substrings below, what are the correct outputs?

var main = "1234567890"
var output = substring(main, 5,1) // output = 
var output = substring(main, 1,5) // output = 
var output = substring(main, 0,5) // output = 
var output = substring(main, 5,0) // output =

Answer 1

使用String.substring函数给出：

var main:String = "1234567890";

trace(main.substring(5, 1));    // gives : 2345
trace(main.substring(1, 5));    // gives : 2345
trace(main.substring(0, 5));    // gives : 12345
trace(main.substring(5, 0));    // gives : 12345

对于此函数，如果第一个参数（startIndex）大于第二个参数（endIndex），则在函数执行之前自动交换参数。所以：

string.substring(5, 1) == string.substring(1, 5)

希望可以提供帮助。

Answer 2

The proper code will be using String.subString() method, and look like this:

var main:String="1234567890";
var output:String=main.subString(5,1); // output = "2345"
var output:String=main.subString(1,5); // output = "2345"
var output:String=main.subString(0,5); // output = "12345"
var output:String=main.subString(5,0); // output = "12345"

The parameters are startIndex and endIndex, they are 0-based, and the character at endIndex is not included in the returned substring.

EDIT: Indeed the manual states that the parameters are swapped if endIndex is smaller than startIndex. Weird, I must say. But if they are equal, the result is an empty string.

Actionscript - substring

2 个答案: