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Strip all whitespaces in string and convert it to an array in Java [duplicate]

This question already has answers here:
How to split a string with any whitespace chars as delimiters
(13 answers)
Closed 5 years ago.
I'm looking for a way to convert a string to an array and strip all whitespaces in the process. Here's what I have:
String[] splitArray = input.split(" ").trim();
But I can't figure out how to get rid of spaces in between the elements.
For example,
input = " 1 2 3 4 5 "
I want splitArray to be:
[1,2,3,4,5]

First off, this input.split(" ").trim(); won't compile since you can't call trim() on an array, but fortunately you don't need to. Your problem is that your regex, " " is treating each space as a split target, and with an input String like so:
String input = " 1 2 3 4 5 ";
You end up creating an array filled with several empty "" String items.
So this code:
String input = " 1 2 3 4 5 ";
// String[] splitArray = input.split("\\s+").trim();
String[] splitArray = input.trim().split(" ");
System.out.println(Arrays.toString(splitArray));
will result in this output:
[1, , , , , , , , 2, 3, 4, , , , , , 5]
What you need to do is to create a regex that greedily groups all the spaces or whitespace characters together, and fortunately we have this ability -- the + operator
Simply use a greedy split with the whitespace regex group
String[] splitArray = input.trim().split("\\s+");
\\s denotes any white-space character, and the trailing + will greedily aggregate one or more contiguous white-space characters together.
And actually, in your situation where the whitespace is nothing but multiples of spaces: " ", this is adequate:
String[] splitArray = input.trim().split(" +");
Appropriate tutorials for this:
short-hand character classes -- discusses \\s
repetition -- discusses the + also ? and * repetition characters

Try:
String[] result = input.split(" ");

Java - How to remove special char in string array?

I'm having an array of strings (phone numbers) and i need to remove +, which is in front of one of the elements (numbers) since it throws an NumberFormatException when i try to cast it to int.
The elements in array are 0888888888 0888123456 +359886001122 and i have already used .split(" ") in order to separate them. I've also tried .split(" +") in order to remove + from the last one, but this didn't work.

You have to use replaceAll instead of split, for example :
"0888888888 0888123456 +359886001122".replaceAll("\\+", "");
this will show you :
0888888888 0888123456 359886001122
//-------------------^------------
Then if you want to split each number you can use split(" ") like this :
String numbers[] = "0888888888 0888123456 +359886001122".replaceAll("\\+", "").split(" ");
System.out.println(Arrays.toString(numbers));
this will give you :
[0888888888, 0888123456, 359886001122]
EDIT
Or like #shmosel said in comment you ca use replace("+", "")

You can replace it with
var lv_numbers = "0888888888 0888123456 +359886001122".replace('+','');

Split uses a regular expression, so you can define to include and optional '+' in the split matcher.
String [] result = "0888888888 0888123456 +359886001122".split("\\s[\\+]{0,1}");

Splitting String in Java with empty elements

I'm reading from a .csv File line by line. One line could look for example as following: String str = "10,1,,,,".
Now I would like to split according to ",": String[] splitted = str.split(","); The problem now is that this only results in 2 elements but I would like to have 5 elements, the first two elements should contain 10 and 1 and the other 3 should be just an empty String.
Another example is String str = "0,,,,," which results in only one element but I would like to have 5 elements.
The last example is String str = "9,,,1,," which gives 2 elements (9 and 1), but I would like to have 5 elements. The first element should be 9 and the fourth element should be 1 and all other should be an empty String.
How can this be done?

You need to use it with -1 parameter
String[] splitted = str.split(",", -1);
This has been discussed before, e.g.
Java: String split(): I want it to include the empty strings at the end
But split really shouldn't be the way you parse a csv, you could run into problems when you have a String value containing a comma
23,"test,test","123.88"
split would split the row into 4 parts:
[23, "test, test", "123.88"]
and I don't think you want that.

split only drops trailing delimeters by default. You can turn this off with
String str = "9,,,1,,";
String[] parts = str.split(",", -1);
System.out.println(Arrays.toString(parts));
prints
[9, , , 1, , ]

Pass -1 (or any negative number, actually) as a second parameter to split:
System.out.println("0,,,,,".split(",", -1).length); // Prints 6.

How can I split a string except when the delimiter is protected by quotes or brackets?

I asked How to split a string with conditions. Now I know how to ignore the delimiter if it is between two characters.
How can I check multiple groups of two characters instead of one?
I found Regex for splitting a string using space when not surrounded by single or double quotes, but I don't understand where to change '' to []. Also, it works with two groups only.
Is there a regex that will split using , but ignore the delimiter if it is between "" or [] or {}?
For instance:
// Input
"text1":"text2","text3":"text,4","text,5":["text6","text,7"],"text8":"text9","text10":{"text11":"text,12","text13":"text14","text,15":["text,16","text17"],"text,18":"text19"}
// Output
"text1":"text2"
"text3":"text,4"
"text,5":["text6","text,7"]
"text8":"text9"
"text10":{"text11":"text,12","text13":"text14","text,15":["text,16","text17"],"text,18":"text19"}

You can use:
text = "\"text1\":\"text2\",\"text3\":\"text,4\",\"text,5\":[\"text6\",\"text,7\"],\"text8\":\"text9\",\"text10\":{\"text11\":\"text,12\",\"text13\":\"text14\",\"text,15\":[\"text,16\",\"text17\"],\"text,18\":\"text19\"}";
String[] toks = text.split("(?=(?:(?:[^\"]*\"){2})*[^\"]*$)(?![^{]*})(?![^\\[]*\\]),+");
for (String tok: toks)
System.out.printf("%s%n", tok);
- RegEx Demo
OUTPUT:
"text1":"text2"
"text3":"text,4"
"text,5":["text6","text,7"]
"text8":"text9"
"text10":{"text11":"text,12","text13":"text14","text,15":["text,16","text17"],"text,18":"text19"}

String.split() returning a "" unexpectedly

I have a simple method splitting a string into an array. It splits it where there are non-letter characters. The line I am using right now is as follows:
String[] words = str.split("[^a-zA-Z]");
So this should split the string where there are only alphabetical characters. But the problem is that when it splits it works for some, but not all. For example:
String str = "!!day--yaz!!";
String[] words = str.split("[^a-zA-Z]");
String result = "";
for (int i = 0; i < words.length; i++) {
result += words[i] + "1 ";
}
return result;
I added the 1 in there to see where the split takes place, becuase i was getting errors on null values. Anyway, when I run this code I get an output of:
1 1 day1 1 yaz1
Why is it splitting between the first two !'s and after one of the -'s, but not after the last two !'s? Why is it even splitting there at all? Any help on this would be great!

It doesn't split before or after it splits ON the matches, therefore you get an empty String between the dashes and the bangs.
This doesn't apply to the trailing bangs, because trailing empty Strings are omitted as described in the javadoc
Trailing empty strings are therefore not included in the resulting
array.

This happens because it indeed uses every non-letter character as a delimiter. It means that string "!" will be splitted into array of 2 empty strings to the left and to the right of the exclamation sign.
Your problem can be solved withing 2 steps.
use "[^a-zA-Z]+" instead of "[^a-zA-Z]". The + will help you to avoid empty string between 2 dashes.
Remove starting and trailing non-letter characters before splitting. This will remove leading and trailing empty strings: str.replaceFirst("[^a-zA-Z]+").replaceFirst("[^a-zA-Z]+$")
Finally your split will look like:
String[] words = str..replaceFirst("[^a-zA-Z]+").replaceFirst("[^a-zA-Z]+$")split("[^a-zA-Z]");

If you want to get rid of some of the extra splits, use split("[^a-zA-Z]+") instead of split("[^a-zA-Z]"). This will match a continuous part of the String that matches the pattern.