Java how to remove strings from JSONArray

Question

JSONArray jsonArray = new JSONArray();
jsonArray.put(1);
jsonArray.put("empty");
jsonArray.put(2);
jsonArray.put(3);
jsonArray.put("empty");
jsonArray.put(4);
jsonArray.put("empty");

lets say we have this jsonArray, there are strings empty, how to remove them without leaving gaps?

• Sujith PS: JSONArray from which API you are using ?
• user3112115: iam using this import org.json.JSONArray
• Karthikeyan Sukkoor: already we have link with solution stackoverflow.com/questions/18497162/…
• AJJ: @KarthikeyanSukkoor the link you pointed out is for javascript. The question is on Java and was tagged in java. There is no splice() in JsonArray in java.

Answer 1

You can use the following code :

for (int i = 0, len = jsonArray.length(); i < len; i++) {
 JSONObject obj = jsonArray.getJSONObject(i);
 String val = jsonArray.getJSONObject(i).getString();
 if (val.equals("empty")) { 
 jsonArray.remove(i);
 }
}

Answer 2

take a look at this post. Make a list to put the indexes of the elements with the "empty" string and iterate over your list (the one with the "empty" elements) saving the indexes of the items to delete. After that, iterate over the previosly saved indexes and use

list.remove(position);

where position takes the value of every item to delente (within the list of index).

Answer 3

Should work with few fixes to Keerthi's code:

for (int i = 0; i < jsonArray.length(); i++) {
 if (jsonArray.get(i).equals("empty")) {
 jsonArray.remove(i);
 }
}

• michali: Note that versions with getString() will not work because first element is not a String...

Answer 4

You can use this following code

JSONArray list = new JSONArray(); 
JSONArray jsonArray = new JSONArray(jsonstring); 
int len = jsonArray.length();
if (jsonArray != null) { 
 for (int i=0;i<len;i++)
 { 
 //Excluding the item string equal to "empty"
 if (!"empty".equals(jsonArray.getString(i)) 
 {
 list.put(jsonArray.get(i));
 }
 } 
 //Now, list JSONArray has no empty string values
}

Answer 5

you can use string replace after converting the array to string as,

 JSONArray jsonArray = new JSONArray();
 jsonArray.put(1);
 jsonArray.put("empty");
 jsonArray.put(2);
 jsonArray.put(3);
 jsonArray.put("empty");
 jsonArray.put(4);
 jsonArray.put("empty");
 System.err.println(jsonArray);
 String jsonString = jsonArray.toString();
 String replacedString = jsonString.replaceAll("\"empty\",", "").replaceAll("\"empty\"", "");
 jsonArray = new JSONArray(replacedString);
 System.out.println(jsonArray);

Before replace:

jsonArray is [1,"empty",2,3,"empty",4,"empty"]

After replace:

jsonArray is [1,2,3,4]