Return strings in array that begin with the initial passed

I have a .txt file which has data for states as given below:

AL,Alab,4860
AK,Alas,7415
AZ,Ariz,6908
AR,Arka,2988


I have made a function which counts how many states there are that start with the initial passed as such:

public int CInitial(char initial)
int total = 0;
for(int i = 0; i < states.length; i++) //states is an array which includes all states present in the .txt file
String testString = states[i].getName(); // getName gets the name of the states present in the .txt file
char stringToCharArray = testString.toCharArray();
for (char output : stringToCharArray)
if(initial == output)
total++;





return total;



This would return the number 4 if "A" is passed and 0 if any other initial is passed as there are 4 states that begin with the letter "A".

Now how can I create a new function that passes a character and returns the name of all the states that begin with that character? For Instance this is the initial return type needed for this, however I'm having troubles starting this. Is the process identical to the countStatesCountByInitial function I created?

public State CByInitial(char initial)
return new State ; //to be completed



State

for (char output : stringToCharArray) {

public String getSomething(char initial)

State

2 Answers
2

Yes, it will be very similar to the countStatesCountByInitial. The main difference is each time you find a match, you want to add the state into the array. Since we don't know the size of the array beforehand, we may want to use a List instead.

countStatesCountByInitial

List

public State getStatesCountByInitial(char initial)
ArrayList<State> found = new ArrayList<>();

// this is the same as before
for(int i = 0; i < states.length; i++)
String testString = states[i].getName();
char stringToCharArray = testString.toCharArray();
for (char output : stringToCharArray)
if(initial == output)
// except here when you find a match, you add it into the list
found.add(states[i]);




// return as array
return found.toArray(new State[found.size()]);



As suggested by Patrick, we can avoid using List by using countStatesCountByInitial to initialize the size of the states.

List

countStatesCountByInitial

public State getStatesCountByInitial(char initial)
int matchSize = countStatesCountByInitial(initial);
States found = new States[matchSize];
int foundIndex = 0;

// this is the same as before
for(int i = 0; i < states.length; i++)
String testString = states[i].getName();
char stringToCharArray = testString.toCharArray();
for (char output : stringToCharArray)
if(initial == output)
// except here when you find a match, you add it into the array
found[foundIndex] = states[i];
foundIndex++;




// return the array
return found;



countStatesCountByInitial

for (char output : stringToCharArray) {

You can done both operations simply by one method.

public static ArrayList<State> getStatesCountByInitial(char initial)
ArrayList selectedStates = new ArrayList<State>();
for(int i = 0; i < states.length; i++)
if(states.charAt(0) == initial)
selectedStates.add(states[i]);


return selectedStates;



This method will return a arraylist.
If you want to get the count, call this method and get the size of the array.

ArrayList<State> statesNew = getStatesCountByInitial('A');
int count = statesNew.size();


Thanks for contributing an answer to Stack Overflow!

But avoid …

To learn more, see our tips on writing great answers.

Required, but never shown

Required, but never shown

By clicking "Post Your Answer", you acknowledge that you have read our updated terms of service, privacy policy and cookie policy, and that your continued use of the website is subject to these policies.