Delete numbers from array

Question

I got an ArrayList "ArrayList1" with content like

0090113itemone ,
1000120itemtwo ,
0090113itemthree

There are always 7 numbers in front of an item .

Now I want to remove the numbers to assign only the items to a ListView. I tried to convert the Array to String with

String[] arr = ArrayList1.toArray(new String[ArrayList1.size()]);

and then use substring to cut the first 7 positions from the string

result.append(arr.substring(0,7));

But this will get me an error Cannot invoke substring(int, int) on the array type String[]

So I would need a way to get rid of these numbers. Either how to solve this error or, if you got a better idea, I'm also open to that.

result.append(arr.substring(0,7)); substring(int,int) over an array? Didn't it through any compilation error? You should iterate through the string array and do a substring. — Samy
– Samy, Commented Dec 20, 2013 at 13:22

kai · Accepted Answer · 2013-12-20 13:19:24Z

1

you have to iterate over the array and do it for every string, because substring() is a method of the string class and not of the array class. The errormessage Cannot invoke substring(int, int) on the array type String[] tell you that you try do build a substring of an Stringarray.

change:

result.append(arr.substring(0,7));

to:

result.append(arr[0].substring(0,7));

and put in in a for-loop:

for(int i = 0; i<arr.length(); i++)
    result.append(arr[i].substring(0,7));

edited Dec 20, 2013 at 13:19

answered Dec 20, 2013 at 13:11

kai

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3 Comments

oli Over a year ago

Now I get an error when I try to put it in the ListView on: 'ArrayAdapter<String> arrayAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, result); lv.setAdapter(arrayAdapter);' The constructor ArrayAdapter<String>(MainActivity, int, StringBuilder) is undefined

kai Over a year ago

because you try to put the stringbuilder into an string list. convert the stringbuilder to an string with StringBuilder.toString()

oli Over a year ago

Only change the error to The constructor ArrayAdapter<String>(MainActivity, int, String) is undefined

nillas · Accepted Answer · 2013-12-20 13:57:39Z

0

The error "Cannot invoke substring(int, int) on the array type String[]" means that the method does not work on this type of object.

It works on a String though.

You don't need to create an Array out of your ArrayList like this:

String[] arr = ArrayList1.toArray(new String[ArrayList1.size()]);

Instead, use your ArrayList right away. I highly recommend renaming it to Java Camel Case: "arrayList1" to avoid confusion with classes. Use Regex to replace numbers in a String. Try running this for-loop:

for (String item : arrayList1) {
    String result = item.replaceAll("[0-9]","");
    System.out.println(result);
}

answered Dec 20, 2013 at 13:57

nillas

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Comments

Tim B · Accepted Answer · 2013-12-20 13:11:53Z

0

for (int i=0;i<arr.length;i++) {
   arr[i] = arr[i].substring(7);
}

answered Dec 20, 2013 at 13:11

Tim B

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Comments

Prabhakaran Ramaswamy · Accepted Answer · 2013-12-20 13:13:08Z

0

Do like this

for (String s:arr) {
    result.append(s.replaceAll("\\d",""));
}

answered Dec 20, 2013 at 13:13

Prabhakaran Ramaswamy

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Comments

Jens Baitinger · Accepted Answer · 2013-12-20 13:17:40Z

0

You have to edit each element before copying it. I'd recoment the following:

List<String> newList = new ArrayList<>();    
for (String element : arrayList1)
{
  String elementWithoutNumber = element.subString(7);
  newList.add(elementWithoutNumber);
}
String[] arr = ArrayList1.toArray(new String[newList.size()]);

answered Dec 20, 2013 at 13:17

community wiki

Jens Baitinger

Comments

Sujith PS · Accepted Answer · 2013-12-20 13:29:07Z

0

Try this code :

for (String s:arr) {
    result.append(s.substring(7,s.length()));
}

edited Dec 20, 2013 at 13:29

answered Dec 20, 2013 at 13:16

Sujith PS

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Comments

Sujith PS · Accepted Answer · 2013-12-20 13:31:58Z

0

Loop through your ArrayList to start with.
Then at least two options you have:

1) Use the String.replace method.

String x = str.replaceAll("\\d", "");

Call this method on each string from your ArrayList.
Then handle the x which you get as you need.

2) But if your strings may contain digits after their
position 7 and you want those digits included, then loop
through the strings and do:

String x = str.substring(7);

Then do what you need with x.

edited Dec 20, 2013 at 13:31

Sujith PS

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answered Dec 20, 2013 at 13:12

peter.petrov

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