Develop Reference

Reverse string without changing the position of special character using regex

class der{
public static void maxLength(String str) {
String s = " ";
s = str.replaceAll("[^a-z]+", " ");
String rev = " ";
char ch[] = s.toCharArray();
for(int i =ch.length-1; i>=0 ; i--){
rev = rev + ch[i];
}
System.out.println(rev);
}
public static void main(String[] args){
String str = "a#utom!at$ion#";
maxLength(str);
}
}
I tried the above with regex function where i first tried to remove special character and then reverse the string. But is there any option to add special character back again to the reverse strings?
My o/p for the current code is this noi ta motu a so in blank space i want to put the special character again.

You may use this Java code:
String str = "a#utom!at$ion#";
// \W+ matches 1+ of any non-word characters
Matcher m = Pattern.compile("\\W+").matcher(str);
StringBuilder sb = new StringBuilder();
int start=0;
// loop through the matches of \W+
while (m.find()) {
// append reverse of substring before current match
// and then the match itself is appended in buffer
sb
.append(new StringBuilder(str.substring(start, m.start())).reverse())
.append(m.group());
start = m.end();
}
// append remaining part after last match in buffer
sb.append(new StringBuilder(str.substring(start)).reverse());
// print the results
System.out.println(sb);
Output:
a#motu!ta$noi#

How to split a String by a comma, but from the second comma

I have a string as:
"model=iPhone12,3,os_version=13.6.1,os_update_exist=1,status=1"
How can I convert this into:
model=iPhone12,3
os_version=13.6.1
os_update_exist=1
status=1

Split the string from the first comma, then re-join the first two elements of the resulting string array.

I doubt there's a "clean" way to do this but this would work for your case:
String str = "model=iPhone12,3,os_version=13.6.1,os_update_exist=1,status=1";
String[] sp = str.split(",");
sp[0] += "," + sp[1];
sp[1] = sp[2];
sp[2] = sp[3];
sp[3] = sp[4];
sp[4] = "";

You can try this:
public String[] splitString(String source) {
// Split the source string based on a comma followed by letters and numbers.
// Basically "model=iPhone12,3,os_version=13.6.1,os_update_exist=1,status=1" will be split
// like this:
// model=iPhone12,3
// ,os_version=13.6.1
// ,os_update_exist=1
// ,status=1"
String[] result = source.split("(?=,[a-z]+\\d*)");
for (int i = 0; i < result.length; i++) {
// Removes the comma at the beginning of the string if present
if (result[i].matches(",.*")) {
result[i] = result[i].substring(1);
}
}
return result;
}

if you are parsing always the same kind of String a regex like this will be do the job
String str = "model=iPhone12,3,os_version=13.6.1,os_update_exist=1,status=1";
Matcher m = Pattern.compile("model=(.*),os_version=(.*),os_update_exist=(.*),status=(.*)").matcher(str);
if (m.find()) {
model = m.group(1)); // iPhone12,3
os = m.group(2)); // 13.6.1
update = m.group(3)); // 1
status = m.group(4)); // 1
}
If you really wants to use a split you can still use that kind of trick
String[] split = str.replaceAll(".*?=(.*?)(,[a-z]|$)", "$1#")
.split("#");
split[0] // iPhone12,3
split[1] // 13.6.1
split[2] // 1
split[3] // 1

Split starting alphabetical characters from numeric characters

I want to split a string so that I get starting alphabetical string(until the first numeric digit occured). And the other alphanumeric string.
E.g.:
I have a string forexample: Nesc123abc456
I want to get following two strings by splitting the above string: Nesc, 123abc456
What I have tried:
String s = "Abc1234avc";
String[] ss = s.split("(\\D)", 2);
System.out.println(Arrays.toString(ss));
But this just removes the first letter from the string.

You could maybe use lookarounds so that you don't consume the delimiting part:
String s = "Abc1234avc";
String[] ss = s.split("(?<=\\D)(?=\\d)", 2);
System.out.println(Arrays.toString(ss));
ideone demo
(?<=\\D) makes sure there's a non-digit before the part to be split at,
(?=\\d) makes sure there's a digit after the part to be split at.

You need the quantifier.
Try
String[] ss = s.split("(\\D)*", 2);
More information here: http://docs.oracle.com/javase/tutorial/essential/regex/quant.html

Didn't you try replaceAll?
String s = ...;
String firstPart = s.replaceAll("[0-9].*", "");
String secondPart = s.substring(firstPart.length());

You can use:
String[] arr = "Nesc123abc456".split("(?<=[a-zA-Z])(?![a-zA-Z])", 2);
//=> [Nesc, 123abc456]

split is a destructive process so you would need to find the index of the first numeric digit and use substrings to get your result. This would also probably be faster than using a regex since those have a lot more heuristics behind them
int split = string.length();
for(int i = 0; i < string.length(); i ++) {
if (Character.isDigit(string.charAt(i)) {
split = i;
break;
}
}
String[] parts = new String[2];
parts[0] = string.substring(0, split);
parts[1] = string.substring(split);

I think this is what you asked:
String s = "Abc1234avc";
String numbers = "";
String chars = "";
for(int i = 0; i < s.length(); i++){
char c = s.charAt(i);
if(Character.isDigit(c)){
numbers += c + "";
}
else {
chars += c + "";
}
}
System.out.println("Numbers: " + numbers + "; Chars: " + chars);

How to split the string in java?

String str = "AlwinX-road-9:00pm-kanchana travels-25365445421";
String[] names = str.split("-");
I want output like following:
AlwinX-road
9:00pm
kanchana travels
25365445421

Use pattern matching to match your requirement
String str = "AlwinX-road-9:00pm-kanchana travels-25365445421";
String regex = "(^[A-Z-a-z ]+)[-]+(\\d+:\\d+pm)[-]([a-z]+\\s+[a-z]+)[-](\\d+)";
Matcher matcher = Pattern.compile( regex ).matcher( str);
while (matcher.find( ))
{
String roadname = matcher.group(1);
String time = matcher.group(2);
String travels = matcher.group(3);
String digits= matcher.group(4);
System.out.println("time="+time);
System.out.println("travels="+travels);
System.out.println("digits="+digits);
}

Since you want to include the delimiter in your first output line, you can do the split, and merge the first two element with a -: -
String[] names = str.split("-");
System.out.println(names[0] + "-" + names[1])
for (int i = 2;i < names.length; i++) {
System.out.println(names[i])
}

The split() method can't distinguish the dash in AlwinX-road and the other dashes in the string, it treats all the dashes the same. You will need to do some sort of post processing on the resulting array. If you will always need the first two strings in the array joined you can just do that. If your strings are more complex you will need to add additional logic to join the strings in the array.

One way you could do it, assuming the first '-' is always part of a two part identifier.
String str = "AlwinX-road-9:00pm-kanchana travels-25365445421";
String[] tokens = str.split("-");
String[] output = new String[tokens.length - 1];
output[0] = tokens[0] + '-' + tokens[1];
System.out.println(output[0]);
for(int i = 1; i < output.length; i++){
output[i] = tokens[i+1];
System.out.println(output[i]);
}

Looks like you want to split (with removal of all dashes but the first one).
String str = "AlwinX-road-9:00pm-kanchana travels-25365445421";
String[] names = str.split("-");
for (String value : names)
{
System.out.println(value);
}
So its produces:
AlwinX
road
9:00pm
kanchana travels
25365445421
Notice that "AlwinX" and "road" we split as well since they had a dash in between. So you will need custom logic to handle this case. here is an example how to do it (I used StringTokenizer):
StringTokenizer tk = new StringTokenizer(str, "-", true);
String firstString = null;
String secondString = null;
while (tk.hasMoreTokens())
{
final String token = tk.nextToken();
if (firstString == null)
{
firstString = token;
continue;
}
if (secondString == null && firstString != null && !token.equals("-"))
{
secondString = token;
System.out.println(firstString + "-" + secondString);
continue;
}
if (!token.equals("-"))
{
System.out.println(token);
}
}
This will produce:
AlwinX-road
9:00pm
kanchana travels
25365445421

from your format, I think you want to split the first one just before the time part. You can do it this way:
String str =yourString;
String beforetime=str.split("-\\d+:\\d+[ap]m")[0]; //this is your first token,
//AlwinX-road in your example
String rest=str.substring(beforetime.length()+1);
String[] restNames=rest.split("-");
If you really need it all together in one array then see the code below:
String[] allTogether=new String[restNames.length+1];//the string with all your tokens
allTogether[0]=beforetime;
System.arraycopy(restNames, 0, allTogether, 1, restNames.length);

If you use "_" as a separator instead of "-": AlwinX-road_9:00pm_kanchana travels_25365445421
New code:
String str = new String("AlwinX-road_9:00pm_kanchana travels_25365445421");
String separator = new String("_");
String[] names = str.split(separator);
for(int i=0; i<names.length; i++){
System.out.println(names[i]);
}

How to Split a string in java based on limit

I have following String and i want to split this string into number of sub strings(by taking ',' as a delimeter) when its length reaches 36. Its not exactly splitting on 36'th position
String message = "This is some(sampletext), and has to be splited properly";
I want to get the output as two substrings follows:
1. 'This is some (sampletext)'
2. 'and has to be splited properly'
Thanks in advance.

A solution based on regex:
String s = "This is some sample text and has to be splited properly";
Pattern splitPattern = Pattern.compile(".{1,15}\\b");
Matcher m = splitPattern.matcher(s);
List<String> stringList = new ArrayList<String>();
while (m.find()) {
stringList.add(m.group(0).trim());
}
Update:
trim() can be droped by changing the pattern to end in space or end of string:
String s = "This is some sample text and has to be splited properly";
Pattern splitPattern = Pattern.compile("(.{1,15})\\b( |$)");
Matcher m = splitPattern.matcher(s);
List<String> stringList = new ArrayList<String>();
while (m.find()) {
stringList.add(m.group(1));
}
group(1) means that I only need the first part of the pattern (.{1,15}) as output.
.{1,15} - a sequence of any characters (".") with any length between 1 and 15 ({1,15})
\b - a word break (a non-character before of after any word)
( |$) - space or end of string
In addition I've added () surrounding .{1,15} so I can use it as a whole group (m.group(1)).
Depending on the desired result, this expression can be tweaked.
Update:
If you want to split message by comma only if it's length would be over 36, try the following expression:
Pattern splitPattern = Pattern.compile("(.{1,36})\\b(,|$)");

The best solution I can think of is to make a function that iterates through the string. In the function you could keep track of whitespace characters, and for each 16th position you could add a substring to a list based on the position of the last encountered whitespace. After it has found a substring, you start anew from the last encountered whitespace. Then you simply return the list of substrings.

Here's a tidy answer:
String message = "This is some sample text and has to be splited properly";
String[] temp = message.split("(?<=^.{1,16}) ");
String part1 = message.substring(0, message.length() - temp[temp.length - 1].length() - 1);
String part2 = message.substring(message.length() - temp[temp.length - 1].length());

This should work on all inputs, except when there are sequences of chars without whitespace longer than 16. It also creates the minimum amount of extra Strings by indexing into the original one.
public static void main(String[] args) throws IOException
{
String message = "This is some sample text and has to be splited properly";
List<String> result = new ArrayList<String>();
int start = 0;
while (start + 16 < message.length())
{
int end = start + 16;
while (!Character.isWhitespace(message.charAt(end--)));
result.add(message.substring(start, end + 1));
start = end + 2;
}
result.add(message.substring(start));
System.out.println(result);
}

If you have a simple text as the one you showed above (words separated by blank spaces) you can always think of StringTokenizer. Here's some simple code working for your case:
public static void main(String[] args) {
String message = "This is some sample text and has to be splited properly";
while (message.length() > 0) {
String token = "";
StringTokenizer st = new StringTokenizer(message);
while (st.hasMoreTokens()) {
String nt = st.nextToken();
String foo = "";
if (token.length()==0) {
foo = nt;
}
else {
foo = token + " " + nt;
}
if (foo.length() < 16)
token = foo;
else {
System.out.print("'" + token + "' ");
message = message.substring(token.length() + 1, message.length());
break;
}
if (!st.hasMoreTokens()) {
System.out.print("'" + token + "' ");
message = message.substring(token.length(), message.length());
}
}
}
}