Develop Reference

How to split string based on length and space using Java

I'm having a string as following in Java. The length of the string is not known and as an example it will be something like below.
String str = "I love programming. I'm currently working with Java and C++."
For some requirement I want to get first 15 characters. Then 30, 45, 70 next characters. Once the string was split if the name was not meaningful then it should be split from nearest space. For the above example output is as following.
String strSpli1 = "I love "; //Since 'programming' is splitting it was sent to next split
String strSpli2 = "programming. I'm currently ";//Since 'working' is splitting it was sent to next split
String strSpli3 = "working with Java and C++.";
Please help me to achieve this.
Updated answer for anybody having this kind of requirement.
String str = "I love programming. I'm currently working with Java and C++.";
String strSpli1 = "";
String strSpli2 = "";
String strSpli3 = "";
try {
strSpli1 = str.substring(15);
int pos = str.lastIndexOf(" ", 16);
if (pos == -1) {
pos = 15;
}
strSpli1 = str.substring(0, pos);
str = str.substring(pos);
try {
strSpli2 = str.substring(45);
int pos1 = str.lastIndexOf(" ", 46);
if (pos1 == -1) {
pos1 = 45;
}
strSpli2 = str.substring(0, pos1);
str = str.substring(pos1);
try {
strSpli3 = str.substring(70);
int pos2 = str.lastIndexOf(" ", 71);
if (pos2 == -1) {
pos2 = 45;
}
strSpli3 = str.substring(0, pos2);
str = str.substring(pos2);
} catch (Exception ex) {
strSpli3 = str;
}
} catch (Exception ex) {
strSpli2 = str;
}
} catch (Exception ex) {
strSpli1 = str;
}
Thank you

use the 2 parameter version of lastIndexOf() to search for space backwards starting from a given position. Example for the first 15 characters:
int pos = str.lastIndexOf(" ", 16);
if (pos == -1) {
pos = 15;
}
String found = str.substring(0, pos);
str = str.substring(pos+1);
this is missing checks like ensuring the string starts with at least 15 characters, or that pos+1 is valid for given length
suggest having a look at java.text.BreakIterator

why you use so many try catch ? just try this.
public class MyClass {
public static void main(String args[]) {
String str = "I love programming. I'm currently working with Java and C++.";
String strSpli1 = "";
String strSpli2 = "";
String strSpli3 = "";
strSpli1 = str.substring(0, 7);
strSpli2 = str.substring(7, 33);
strSpli3 = str.substring(34, str.length());
System.out.println(strSpli1+"\n");
System.out.println(strSpli2+"\n");
System.out.println(strSpli3+"\n");
}
use substring(start index, end index).

Masking - Address with Stars (asteriks) - If length of Array is 1?

I have an array out of bounds for this case.
If I do:
String address = "100 Point St Apt B"
It should be masked too: 100 Po*** St Apt *
If I do:
String address = "100 Point St Apt 132"
It is masked too: 100 Po*** St Apt ***
Can somebody tell me what I am doing wrong here? Thank you!!
public String mask(String address) {
String[] splitAddress = address.split(" ");
StringBuilder stringBuilder = new StringBuilder();
String maskedAddress = "";
String streetNum = splitAddress[0];
stringBuilder.append(streetNum + " ");
for (int i = 1; i < splitAddress.length; i++) {
String splitFirstTwoCharacters = splitAddress[i].substring(0, 2);
String remainingCharactersOfAddress = splitAddress[i].substring(2);
String maskAddress = remainingCharactersOfAddress.replaceAll(".", "*");
maskedAddress = stringBuilder.append(splitFirstTwoCharacters).append(maskAddress + " ").toString().trim();
}
return maskedAddress;
}

When you do splitAddress[i].substring(0, 2) one of the splitAddress parts is B which does not have an endIndex of 2. Therefore it is out of bounds.

Issue is you are running substring without checking the length of the string.
Here is the fix without too many changes to your existing code:
for (int i = 1; i < splitAddress.length; i++) {
if (splitAddress[i].length() <= 2) {
stringBuilder.append(splitAddress[i] + " ");
continue;
}
String splitFirstTwoCharacters = splitAddress[i].substring(0, 2);
String remainingCharactersOfAddress = splitAddress[i].substring(2);
String maskAddress = remainingCharactersOfAddress.replaceAll(".", "*");
maskedAddress = stringBuilder.append(splitFirstTwoCharacters).append(maskAddress + " ").toString().trim();
}
return stringBuilder.toString().trim();

Replace word in Java

There is some line, for example "1 qqq 4 aaa 2" and list {aaa, qqq}. I must change all words (consists only from letters) on words from list. Answer on this example "1 aaa 4 qqq 2". Try
StringTokenizer tokenizer = new StringTokenizer(str, " ");
while (tokenizer.hasMoreTokens()){
tmp = tokenizer.nextToken();
if(tmp.matches("^[a-z]+$"))
newStr = newStr.replaceFirst(tmp, words.get(l++));
}
But it's not working. In result I have the same line.
All my code:
String space = " ", tmp, newStr;
Scanner stdin = new Scanner(System.in);
while (stdin.hasNextLine()) {
int k = 0, j = 0, l = 0;
String str = stdin.nextLine();
newStr = str;
List<String> words = new ArrayList<>(Arrays.asList(str.split(" ")));
words.removeIf(new Predicate<String>() {
#Override
public boolean test(String s) {
return !s.matches("^[a-z]+$");
}
});
Collections.sort(words);
StringTokenizer tokenizer = new StringTokenizer(str, " ");
while (tokenizer.hasMoreTokens()){
tmp = tokenizer.nextToken();
if(tmp.matches("^[a-z]+$"))
newStr = newStr.replaceFirst(tmp, words.get(l++));
}
System.out.printf(newStr);
}

I think the problem might be that replaceFirst() expects a regular expression as first parameter and you are giving it a String.
Maybe try
newStr = newStr.replaceFirst("^[a-z]+$", words.get(l++));
instead?
Update:
Would that be a possibility for you:
StringBuilder _b = new StringBuilder();
while (_tokenizer.hasMoreTokens()){
String _tmp = _tokenizer.nextToken();
if(_tmp.matches("^[a-z]+$")){
_b.append(words.get(l++));
}
else{
_b.append(_tmp);
}
_b.append(" ");
}
String newStr = _b.toString().trim();
Update 2:
Change the StringTokenizer like this:
StringTokenizer tokenizer = new StringTokenizer(str, " ", true);
That will also return the delimiters (all the spaces).
And then concatenate the String like this:
StringBuilder _b = new StringBuilder();
while (_tokenizer.hasMoreTokens()){
String _tmp = _tokenizer.nextToken();
if(_tmp.matches("^[a-z]+$")){
_b.append(words.get(l++));
}
else{
_b.append(_tmp);
}
}
String newStr = _b.toString().trim();
That should work.
Update 3:
As #DavidConrad mentioned StrinkTokenizer should not be used anymore. Here is another solution with String.split():
final String[] _elements = str.split("(?=[\\s]+)");
int l = 0;
for (int i = 0; i < _tokenizer.length; i++){
if(_tokenizer[i].matches("^[a-z]+$")){
_b.append(_arr[l++]);
}
else{
_b.append(_tokenizer[i]);
}
}

Just out of curiosity, another solution (the others really don't answer the question), which takes the input line and sorts the words alphabetically in the result, as you commented in your question.
public class Replacer {
public static void main(String[] args) {
Replacer r = new Replacer();
Scanner in = new Scanner(System.in);
while (in.hasNextLine()) {
System.out.println(r.replace(in.nextLine()));
}
}
public String replace(String input) {
Matcher m = Pattern.compile("([a-z]+)").matcher(input);
StringBuffer sb = new StringBuffer();
List<String> replacements = new ArrayList<>();
while (m.find()) {
replacements.add(m.group());
}
Collections.sort(replacements);
m.reset();
for (int i = 0; m.find(); i++) {
m.appendReplacement(sb, replacements.get(i));
}
m.appendTail(sb);
return sb.toString();
}
}

Multiline strings concatenation in Java

I'm looking for some help. What is the easiest way to concatenate multiline strings in Java and print it after ?
For example : I've got two strings :
String turtle1 = " _\r\n .-./*)\r\n _/___\\/\r\n U U\r";
String turtle2 = " _\r\n .-./*)\r\n _/___\\/\r\n U U\r";
And I want to get this result in the Java Eclipse console :
_ _
.-./*) .-./*)
_/___\/ _/___\/
U U U U
I've already try some algorithms to divide my strings in differents parts and after re-concatenate it. But it was without success.
I know there are StringBuffer class and StringBuilder class but after some research, I didn't found something that correspond to my need.
Thanks in advance for your help.

See my example below, should be self explaining.
public class Turtle {
private static final String returnpattern = "\r\n";
public static void main(String[] args) {
// the data to run through
String turtle1 = " _\r\n .-./*)\r\n _/___\\/\r\n U U\r\n";
String turtle2 = " _\r\n .-./*)\r\n _/___\\/\r\n U U\r\n";
// split the data into individual parts
String[] one = turtle1.split(returnpattern);
String[] two = turtle2.split(returnpattern);
// find out the longest String in data set one
int longestString = 0;
for (String s : one) {
if (longestString < s.length()) {
longestString = s.length();
}
}
// loop through parts and build new string
StringBuilder b = new StringBuilder();
for (int i = 0; i < one.length; i++) {
String stringTwo = String.format("%1$" + longestString + "s", two[i]); // left pad the dataset two to match
// length
b.append(one[i]).append(stringTwo).append(returnpattern);
}
// output
System.out.println(b);
}
}

Just for fun, here is another solution using streams, prepared for more than two turtles to be shown side-by-side:
public static void main(String[] args) {
String turtle1 = " _\r\n .-./*)\r\n _/___\\/\r\n U U\r";
String turtle2 = " _\r\n .-./*)\r\n _/___\\/\r\n U U\r";
// split lines into fragments
List<List<String>> fragments = Stream.of(turtle1, turtle2)
.map(x -> Stream.of(x.split("\\r\\n?|\\n")).collect(Collectors.toList()))
.collect(Collectors.toList());
// make all lists same length by adding empty lines as needed
int lines = fragments.stream().mapToInt(List::size).max().orElse(0);
fragments.forEach(x -> x.addAll(Collections.nCopies(lines - x.size(), "")));
// pad all fragments to maximum width (per list)
List<List<String>> padded = fragments.stream().map(x -> {
int width = x.stream().mapToInt(String::length).max().orElse(0);
return x.stream().map(y -> String.format("%-" + width + "s", y)).collect(Collectors.toList());
}).collect(Collectors.toList());
// join corresponding fragments to result lines, and join result lines
String result = IntStream.range(0, lines)
.mapToObj(i -> padded.stream().map(x -> x.get(i)).collect(Collectors.joining()))
.collect(Collectors.joining(System.lineSeparator()));
System.out.println(result);
}

Not so pretty but works:
String turtle1 = " _\r\n .-./*)\r\n _/___\\/\r\n U U\r\n";
String turtle2 = " _\r\n .-./*)\r\n _/___\\/\r\n U U\r\n";
String[] turtle1Lines = turtle1.split("\r\n");
String[] turtle2Lines = turtle2.split("\r\n");
StringBuilder sb = new StringBuilder();
int turtle1Width = 0;
for (int i = 0; i < 4; i++) {
if (turtle1Lines[i].length() > turtle1Width) {
turtle1Width = turtle1Lines[i].length();
}
}
for (int i = 0; i < 4; i++) {
sb.append(turtle1Lines[i]);
for (int j = turtle1Width - turtle1Lines[i].length(); j > 0; j--) {
sb.append(' ');
}
sb.append(turtle2Lines[i]);
sb.append("\r\n");
}
String turtles = sb.toString();

I'm here too ;)
public class Test {
static String turtle1 = " _\r\n .-./*)\r\n _/___\\/\r\n U U\r".replace("\r", "");
static String turtle2 = " _\r\n .-./*)\r\n _/___\\/\r\n U U\r".replace("\r", "");
public static int countRows(String string){
return string.length() - string.replace("\n", "").length() + 1;
}
public static int getMaxLength(String string){
int maxLength = 0;
int currentLength = 0;
char[] data = string.toCharArray();
for(Character c : data){
if(c != '\n'){
if(++currentLength > maxLength) {
maxLength = currentLength;
}
}else{
currentLength = 0;
}
}
return maxLength;
}
public static String[] toStringArray(String string){
int length = getMaxLength(string);
int rows = countRows(string);
String[] result = new String[rows];
int last = 0;
for(int i = 0; i < rows; i++){
int temp = string.indexOf("\n", last);
String str;
if(temp != -1) {
str = string.substring(last, temp);
}else{
str = string.substring(last);
}
while(str.length() < length){
str += " ";
}
result[i] = str;
last = temp + 1;
}
return result;
}
public static String concatMultilineStrings(String first, String second){
StringBuilder sb = new StringBuilder();
String[] arrayFirst = toStringArray(first);
String[] arraySecond = toStringArray(second);
if(arrayFirst.length != arraySecond.length){
System.exit(69);
}
for(int i = 0; i < arrayFirst.length; i++){
sb.append(arrayFirst[i]);
sb.append(arraySecond[i]);
sb.append("\n");
}
return sb.toString();
}
public static void main(String[] args) {
System.out.println(concatMultilineStrings(turtle1, turtle2));
}
}

Words inside square brackes - RegExp

String linkPattern = "\\[[A-Za-z_0-9]+\\]";
String text = "[build]/directory/[something]/[build]/";
RegExp reg = RegExp.compile(linkPattern,"g");
MatchResult matchResult = reg.exec(text);
for (int i = 0; i < matchResult.getGroupCount(); i++) {
System.out.println("group" + i + "=" + matchResult.getGroup(i));
}
I am trying to get all blocks which are encapsulated by squared bracets form a path string:
and I only get group0="[build]" what i want is:
1:"[build]" 2:"[something]" 3:"[build]"
EDIT:
just to be clear words inside the brackets are generated with random text
public static String genText()
{
final int LENGTH = (int)(Math.random()*12)+4;
StringBuffer sb = new StringBuffer();
for (int x = 0; x < LENGTH; x++)
{
sb.append((char)((int)(Math.random() * 26) + 97));
}
String str = sb.toString();
str = str.substring(0,1).toUpperCase() + str.substring(1);
return str;
}
EDIT 2:
JDK works fine, GWT RegExp gives this problem
SOLVED:
Answer from Didier L
String linkPattern = "\\[[A-Za-z_0-9]+\\]";
String result = "";
String text = "[build]/directory/[something]/[build]/";
RegExp reg = RegExp.compile(linkPattern,"g");
MatchResult matchResult = null;
while((matchResult=reg.exec(text)) != null){
if(matchResult.getGroupCount()==1)
System.out.println( matchResult.getGroup(0));
}

I don't know which regex library you are using but using the one from the JDK it would go along the lines of
String linkPattern = "\\[[A-Za-z_0-9]+\\]";
String text = "[build]/directory/[something]/[build]/";
Pattern pat = Pattern.compile(linkPattern);
Matcher mat = pat.matcher(text);
while (mat.find()) {
System.out.println(mat.group());
}
Output:
[build]
[something]
[build]

Try:
String linkPattern = "(\\[[A-Za-z_0-9]+\\])*";
EDIT:
Second try:
String linkPattern = "\\[(\\w+)\\]+"
Third try, see http://rubular.com/r/eyAQ3Vg68N