How to replace a whole string with another in an array in Java

Question

I want to replace, say String oldString with String newString in an Array along the lines of:

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Answer 1

You don't need to use replace() in this case, since you are already checking that text[i] is equal to oldString, which means you are replacing the entire String, which means assignment is sufficient:

for (int i = 0; i < text.length; i++) {
   if (text[i].equals(oldString)) {
      text[i] = newString;
   }
}

If, on the other hand, you wanted to replace a sub-string of text[i] which is equal to oldString to newString, you could write:

for (int i = 0; i < text.length; i++) {
    text[i] = text[i].replace(oldString,newString);
}

Answer 2

You can use IntStream over the indices of this array and process certain strings in a certain way:

String[] text = {"Lorem", "oldString", "dolor", "sit", "amet"};

IntStream.range(0, text.length)
        // to filter the certain strings, or you
        // can skip this line to process each string
        .filter(i -> text[i].equals("oldString"))
        // processing a string
        .forEach(i -> text[i] = text[i].replace("oldString", "newString"));

System.out.println(Arrays.toString(text));
// [Lorem, newString, dolor, sit, amet]

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^{See also: Replace certain string in array of strings}