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Using methods on every item in an Array

开发者 https://www.devze.com 2023-03-05 09:25 出处:网络
I have a string array that is being filled dynamically.... I would like to run this function: String[] name = request.getParameterValues(\"name\");

I have a string array that is being filled dynamically.... I would like to run this function:

String[] name = request.getParameterValues("name");
myString = name.substring(0, name.length() - 2);  

Now, I know that this wont run, because substring and length methods aren't used for the whole array. 开发者_如何学GoSince i dont know how many items will be in this array at any given run time, is there anyway to run the substring/length function for every item in this array?


Yes, use you can use length field of the name array. Like this:

for (int i = 0; i < name.length; ++i)
{
    String s = name[i];
    String sbtr = s.substring(0, s.length() - 2);
}

Or a better approach would be this:

for (String s: name)
{
    String sbtr = s.substring(0, s.length() - 2);
}


Modern versions of Java (i.e Java 5 and later) have a special for syntax for arrays (and iterables):

String[] name = request.getParameterValues("name");
for (String s: name) {
    String myString = s.substring(0, s.length() - 2);  
}


You'd use a for loop. There are a couple different ways to do this. The most basic way:

String[] names = request.getParameterValues("name");

for (int i=0; i<names.length; i++)
{
    String name = names[i];
    String myString = name.substring(0, name.length() - 2);
}

Or you can use the "enhanced for" (also called a "for-each" — it's just syntactic sugar):

String[] names = request.getParameterValues("name");

for (String name : names)
{
    String myString = name.substring(0, name.length() - 2);
}
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