CODEWITHSUNDEEP
javaarrays
wd40
wd40

Reputation: 3

How to index a string array using a variable?

I mostly familiar with Lua and just getting into Java. Below is the code I am trying to expand upon.

s1 = getResources().getStringArray(R.array.programming_languages);

What do I do if I want programming_langugages to be determined by a variable?

testStr = "programming_languages";

How can I go about doing something similar to below, where testStr is indexed? Below is similar to how I have done it in Lua, so I don't know what else to do, or even search for.

testStr = "programming_languages";

s1 = getResources().getStringArray(R.array[testStr]);

Upvotes: 0

Views: 95

Answers (1)

Mark Bramnik
Mark Bramnik

Reputation: 42481

In java arrays are represented by square brackets:

String [] programmingLanguages = ...

You can initialize in-place:

String [] programmingLanguages = {"C", "C++", "Java", "Lua"};

Or initialize by index:

String [] programmingLanguages = new String [4];
programmingLanguages[0] = "C";
programmingLanguages[1] = "C++";
programmingLanguages[2] = "Java";
programmingLanguages[3] = "Lua";

You can iterate over arrays, access by index and everything:

for(String language : programmingLanguages) {
    System.out.println(language);
}

Or:

for(int index=0; index < programmingLanguages.length; i++) {
    System.out.println(programmingLanguages[index]);
}

Note that you can't change the size of the array after the memory for it has been allocated, so programmingLanguage[5]="Pascal" will throw an exception in runtime.

This might be too restrictive in a real life code challenges, so usually in Java people tend to use java.util.List interface and its well-known implementation java.util.ArrayList:

List<String> programmingLanguages = new ArrayList<>(); // note, no size specified in advance
programmingLanguages.add("C"); 
programmingLanguages.add("C++");
programmingLanguages.add("Java");
programmingLanguages.add("Lua");

Upvotes: 2

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