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Store parts of string in a string array

I have a string tajmahal.txt sarjan.pdf noorjahan.exe. I want to store this string in a string array such that ar[0] = tajmahal.txt, ar[1] = sarjan.pdf and ar[2] = noorjahan.exe. How can I do it without using any build functions in java (because I am using j2me which does not support many j2se functions). Any help would be great. Thanks in advance.

Since String.split is not available. You can see the implementation of split from this answer
public static String[] Split(String splitStr, String delimiter) {
StringBuffer token = new StringBuffer();
Vector tokens = new Vector();
// split
char[] chars = splitStr.toCharArray();
for (int i=0; i < chars.length; i++) {
if (delimiter.indexOf(chars[i]) != -1) {
// we bumbed into a delimiter
if (token.length() > 0) {
tokens.addElement(token.toString());
token.setLength(0);
}
} else {
token.append(chars[i]);
}
}
// don't forget the "tail"...
if (token.length() > 0) {
tokens.addElement(token.toString());
}
// convert the vector into an array
String[] splitArray = new String[tokens.size()];
for (int i=0; i < splitArray.length; i++) {
splitArray[i] = (String)tokens.elementAt(i);
}
return splitArray;
}

String str="tajmahal.txt sarjan.pdf noorjahan.exe";
StringTokenizer st=new StringTokenizer(str," ");
String[] arr=new String[st.countTokens()];
int i=0;
while (st.hasMoreElements()){
arr[i]=st.nextToken();
i++;
}

There are implementations of StringTokenizer in J2me.
check out this example to help you out with the task.
StringTokenizer token;
token = new StringTokenizer(str);
int i=0;
while(token.hasMoreElements()){
ar[i++]= tok.nextToken();
}

It depends on which Java ME configuration/profile set you use.
When it comes to CLDC/MIDP, where there is no collections, StringTokenizer, split(), and so on.
count those space(' ')s first.
prepare a String[count + 1].
split each token while buffering characters with a StringBuffer.
static String[] split(final String string) {
// count spaces
int spaces = 0;
for (int i = 0; i < string.length(); i++) {
if (string.charAt(i) == 0x20) {
spaces++;
}
}
// prepare the array and buffer
final String[] split = new String[spaces + 1];
final StringBuffer buffer = new StringBuffer();
int index = 0;
for (int i = 0; i < string.length(); i++) {
if (string.charAt(i) == 0x20) {
split[index++] = buffer.toString();
buffer.delete(0, buffer.length());
continue;
}
buffer.append(string.charAt(i));
}
return split;
}

Cut off last half of String

I need to cut off half of a user-entered string. I've tried this and it didn't work:
Scanner sc = new Scanner(System.in);
String nameOne = sc.nextLine();
chars[] oneChars = new char[nameOne.length];
double oneLength = oneChars.length / 2;
Math.round(oneLength);
int oneLen = (int)oneLength;
String nameOneFinal = "";
for(int i = 0; i == oneLen--; i++) {
oneChars[i] = oneChars[oneLen];
nameOneFinal = nameOneFinal + oneChars[i];
}

final int mid = nameOne.length() / 2;
String[] parts = {
nameOne.substring(0, mid), // 1st part
nameOne.substring(mid), // 2nd part
};

using substring method ... you can do it
Ex:
public String extraEnd(String str) {
String s = str.substring(str.length()/2);//it will have the last half of string
return s ;
}

Use SubString method to get this
String str = "CutThisBytwo";
int len = str.length();
String firstHalfStr = str.substring(0, len/2);
String secondHalfStr = str.substring(len/2,len );
System.out.println(firstHalfStr);
System.out.println(secondHalfStr);

The easy way: using String.substring(int index1, int index2)
The hard way:
String new = "";
for(int i = 0; (i < old.length() - 1) / 2; i++){
new += old.charAt(i);
}
If it's for a homework, the hard way might get you brownie points, but if not just stick to the easy way.

How can I split a string into words in Java without using String.split()?

My teacher specifically requested that we split a sentence into words without using String.split(). I've done it using a Vector (which we haven't learned), a while-loop, and substrings. What are other ways of accomplishing this? (preferably without using Vectors/ArrayLists).

I believe that your teacher is asking you to process the string yourself (without using any other libraries to do it for you). Check to see if this is the case - if you can use them, there are things such as StringTokenizer, Pattern, and Scanner to facilitate string processing.
Otherwise...
You will need a list of word separators (such as space, tab, period, etc...) and then walk the array, building a string a character at a time until you hit the word separator. After finding a complete word (you have encountered a word separator character), save it the variable out into your structure (or whatever is required), reset the variable you are building the word in and continue.

Parsing the string character by character, copying each character into a new String, and stopping when you reach a white space character. Then start a new string and continue until you reach the end of the original string.

You can use java.util.StringTokenizer to split a text using desired delimiter. Default delimiter is SPACE/TAB/NEW_LINE.
String myTextToBeSplit = "This is the text to be split into words.";
StringTokenizer tokenizer = new StringTokenizer( myTextToBeSplit );
while ( tokinizer.hasMoreTokens()) {
String word = tokinizer.nextToken();
System.out.println( word ); // word you are looking in
}
As an alternate you can also use java.util.Scanner
Scanner s = new Scanner(myTextToBeSplit).useDelimiter("\\s");
while( s.hasNext() ) {
System.out.println(s.next());
}
s.close();

You can use java.util.Scanner.

import java.util.Arrays;
public class ReverseTheWords {
public static void main(String[] args) {
String s = "hello java how do you do";
System.out.println(Arrays.toString(ReverseTheWords.split(s)));
}
public static String[] split(String s) {
int count = 0;
char[] c = s.toCharArray();
for (int i = 0; i < c.length; i++) {
if (c[i] == ' ') {
count++;
}
}
String temp = "";
int k = 0;
String[] rev = new String[count + 1];
for (int i = 0; i < c.length; i++) {
if (c[i] == ' ') {
rev[k++] = temp;
temp = "";
} else
temp = temp + c[i];
}
rev[k] = temp;
return rev;
}
}

YOu can use StringTokenizer
http://www.java-samples.com/showtutorial.php?tutorialid=236

Or use a Pattern (also known as a regular expression) to try to match the words.

Use a Scanner with ctor (String)
regular expressions and match
StringTokenizer
iterating yourself char by char
recursive iteration

Without using a Vector/List (and without manually re-implementing their ability to re-size themselves for your function), you can take advantage of the simple observation that a string of length N cannot have more than (N+1)/2 words (in integer division). You can declare an array of strings of that size, populate it the same way you populated that Vector, and then copy the results to an array of the size of the number of words you found.
So:
String[] mySplit( String in ){
String[] bigArray = new String[ (in.length()+1)/2 ];
int numWords = 0;
// Populate bigArray with your while loop and keep
// track of the number of words
String[] result = new String[numWords];
// Copy results from bigArray to result
return result;
}

public class MySplit {
public static String[] mySplit(String text,String delemeter){
java.util.List<String> parts = new java.util.ArrayList<String>();
text+=delemeter;
for (int i = text.indexOf(delemeter), j=0; i != -1;) {
parts.add(text.substring(j,i));
j=i+delemeter.length();
i = text.indexOf(delemeter,j);
}
return parts.toArray(new String[0]);
}
public static void main(String[] args) {
String str="012ab567ab0123ab";
String delemeter="ab";
String result[]=mySplit(str,delemeter);
for(String s:result)
System.out.println(s);
}
}

public class sha1 {
public static void main(String[] args) {
String s = "hello java how do you do";
System.out.println(Arrays.toString(sha1.split(s)));
}
public static String[] split(String s) {
int count = 0;
char[] c = s.toCharArray();
for (int i = 0; i < c.length; i++) {
if (c[i] == ' ') {
count++;
}
}
String temp = "";
int k = 0;
String[] rev = new String[count + 1];
for (int i = c.length-1; i >= 0; i--) {
if (c[i] == ' ') {
rev[k++] = temp;
temp = "";
} else
temp = temp + c[i];
}
rev[k] = temp;
return rev;
}
}

Simple touch.! Improve if you want to.
package com.asif.test;
public class SplitWithoutSplitMethod {
public static void main(String[] args) {
split('#',"asif#is#handsome");
}
static void split(char delimeter, String line){
String word = "";
String wordsArr[] = new String[3];
int k = 0;
for(int i = 0; i <line.length(); i++){
if(line.charAt(i) != delimeter){
word+= line.charAt(i);
}else{
wordsArr[k] = word;
word = "";
k++;
}
}
wordsArr[k] = word;
for(int j = 0; j <wordsArr.length; j++)
System.out.println(wordsArr[j]);
}
}

Please try this .
public static String[] mysplit(String mystring) {
String string=mystring+" "; //append " " bcz java string does not hava any ending character
int[] spacetracker=new int[string.length()];// to count no. of spaces in string
char[] array=new char[string.length()]; //store all non space character
String[] tokenArray=new String[string.length()];//to return token of words
int spaceIndex=0;
int parseIndex=0;
int arrayIndex=0;
int k=0;
while(parseIndex<string.length())
{
if(string.charAt(parseIndex)==' '||string.charAt(parseIndex)==' ')
{
spacetracker[spaceIndex]=parseIndex;
spaceIndex++;
parseIndex++;
}else
{
array[arrayIndex]=string.charAt(parseIndex);
arrayIndex++;
parseIndex++;
}
}
for(int i=0;i<spacetracker.length;i++)
{
String token="";
for(int j=k;j<(spacetracker[i])-i;j++)
{
token=token+array[j];
k++;
}
tokenArray[i]=token;
//System.out.println(token);
token="";
}
return tokenArray;
}
Hope this helps

import java.util.*;
class StringSplit {
public static void main(String[] args)
{
String s="splitting a string without using split()";
ArrayList<Integer> al=new ArrayList<Integer>(); //Instead you can also use a String
ArrayList<String> splitResult=new ArrayList<String>();
for(int i=0;i<s.length();i++)
if(s.charAt(i)==' ')
al.add(i);
al.add(0, 0);
al.add(al.size(),s.length());
String[] words=new String[al.size()];
for(int j=0;j<=words.length-2;j++)
splitResult.add(s.substring(al.get(j),al.get(j+1)).trim());
System.out.println(splitResult);
}
}
Time complexity: O(n)

You can use java Pattern to do it in easy way.
package com.company;
import java.util.regex.Pattern;
public class umeshtest {
public static void main(String a[]) {
String ss = "I'm Testing and testing the new feature";
Pattern.compile(" ").splitAsStream(ss).forEach(s -> System.out.println(s));
}
}

You can also use String.substring or charAt[].

Dividing a StringBuffer into smaller parts

I have a large stringbuffer which i would like to break into smaller parts. The string buffer looks like this
"name1+name2+name3+name4+..........+name2000"
Where
name1=john
name2=prince
and so on.
(You get the idea.name1,name2,name3 stand for actual names of varying length)
Now i would like to store the names in a string array with each positon containing a 200 names.
string[0]="name1+name2+name3+........+name200";
string[1]="name201+name202+...."
How would i go about achieving this task?

StringTokenizer str = new StringTokenizer(<StringBufferObject>);
int count = 0;
int arrCount = 0;
StringBuffer temp;
String[] stringArr = new String[x];
while(str.hasMoreTokens()) {
count++;
if(count != 200) {
temp.append(str.nextToken());
}
else {
stringArr[arrCount] = temp;
temp.delete(0,temp.length());
count = 0;
arrCount++;
}

It would be a lot easier to split a String using String.split() if that's possible:
/* something like this */
String arrayOfStrings = inputString.split("\+");
If you have to keep it as a StringBuffer you'll have to loop over the input and tokenize it yourself.
I guess it would look something like this:
public String[] getTwoHundredStrings(StringBuffer inputBuff, String someToken)
{
String [] nameArray = new String [200];
int currentPos = 0;
int nextPos = 0;
for ( int i = 0; i < 200; i ++ ) {
nextPos = inputBuff.indexOf(someToken, currentPos);
if ( nextPos < 0 ) {
break;
}
String nextName = inputBuff.substring(currentPos, nextPos);
nameArray[i] = nextName;
currentPos = nextPos;
}
/* do some cleanup if nameArray has less than 200 elements */
return nameArray;

You must have some delimiter between each name. To break the string we should have some delimiter.
If you have delimiter you can use subString() in for loop.

try to use
String[] tempNames = new String(namesBuffer).split("+");
and then
int length = (tempNames.length / 200)+ (tempName.length % 200)
String[] names = new String[length];
for(int i = 0 ; i< tempNames.length ; i++){
for(int j = 0 ; j < length ; j++)
names[j] = tempNames[i];
}
hope this helps

Split on "+", using String.split("\\+")
Get chucks, in smaller arrays, Arrays.copyOfRange(...)
Join using Guava Joiner like Joiner.on("+").join(smallerArray)

Convert String to int array in java

I have one string:
String arr = "[1,2]";
ie "[1,2]" is like a single String.
How do I convert this arr to int array in java?

String arr = "[1,2]";
String[] items = arr.replaceAll("\\[", "").replaceAll("\\]", "").replaceAll("\\s", "").split(",");
int[] results = new int[items.length];
for (int i = 0; i < items.length; i++) {
try {
results[i] = Integer.parseInt(items[i]);
} catch (NumberFormatException nfe) {
//NOTE: write something here if you need to recover from formatting errors
};
}

Using Java 8's stream library, we can make this a one-liner (albeit a long line):
String str = "[1, 2, 3, 4, 5, 6, 7, 8, 9, 0]";
int[] arr = Arrays.stream(str.substring(1, str.length()-1).split(","))
.map(String::trim).mapToInt(Integer::parseInt).toArray();
System.out.println(Arrays.toString(arr));
substring removes the brackets, split separates the array elements, trim removes any whitespace around the number, parseInt parses each number, and we dump the result in an array. I've included trim to make this the inverse of Arrays.toString(int[]), but this will also parse strings without whitespace, as in the question. If you only needed to parse strings from Arrays.toString, you could omit trim and use split(", ") (note the space).

final String[] strings = {"1", "2"};
final int[] ints = new int[strings.length];
for (int i=0; i < strings.length; i++) {
ints[i] = Integer.parseInt(strings[i]);
}

It looks like JSON - it might be overkill, depending on the situation, but you could consider using a JSON library (e.g. http://json.org/java/) to parse it:
String arr = "[1,2]";
JSONArray jsonArray = (JSONArray) new JSONObject(new JSONTokener("{data:"+arr+"}")).get("data");
int[] outArr = new int[jsonArray.length()];
for(int i=0; i<jsonArray.length(); i++) {
outArr[i] = jsonArray.getInt(i);
}

Saul's answer can be better implemented splitting the string like this:
string = string.replaceAll("[\\p{Z}\\s]+", "");
String[] array = string.substring(1, string.length() - 1).split(",");

try this one, it might be helpful for you
String arr= "[1,2]";
int[] arr=Stream.of(str.replaceAll("[\\[\\]\\, ]", "").split("")).mapToInt(Integer::parseInt).toArray();

You can do it easily by using StringTokenizer class defined in java.util package.
void main()
{
int i=0;
int n[]=new int[2];//for integer array of numbers
String st="[1,2]";
StringTokenizer stk=new StringTokenizer(st,"[,]"); //"[,]" is the delimeter
String s[]=new String[2];//for String array of numbers
while(stk.hasMoreTokens())
{
s[i]=stk.nextToken();
n[i]=Integer.parseInt(s[i]);//Converting into Integer
i++;
}
for(i=0;i<2;i++)
System.out.println("number["+i+"]="+n[i]);
}
Output :-number[0]=1
number[1]=2

String str = "1,2,3,4,5,6,7,8,9,0";
String items[] = str.split(",");
int ent[] = new int[items.length];
for(i=0;i<items.length;i++){
try{
ent[i] = Integer.parseInt(items[i]);
System.out.println("#"+i+": "+ent[i]);//Para probar
}catch(NumberFormatException e){
//Error
}
}

If you prefer an Integer[] instead array of an int[] array:
Integer[]
String str = "[1,2]";
String plainStr = str.substring(1, str.length()-1); // clear braces []
String[] parts = plainStr.split(",");
Integer[] result = Stream.of(parts).mapToInt(Integer::parseInt).boxed().toArray(Integer[]::new);
int[]
String str = "[1,2]";
String plainStr = str.substring(1, str.length()-1); // clear braces []
String[] parts = plainStr.split(",");
int[] result = Stream.of(parts).mapToInt(Integer::parseInt).toArray()
This works for Java 8 and higher.

In tight loops or on mobile devices it's not a good idea to generate lots of garbage through short-lived String objects, especially when parsing long arrays.
The method in my answer parses data without generating garbage, but it does not deal with invalid data gracefully and cannot parse negative numbers. If your data comes from untrusted source, you should be doing some additional validation or use one of the alternatives provided in other answers.
public static void readToArray(String line, int[] resultArray) {
int index = 0;
int number = 0;
for (int i = 0, n = line.length(); i < n; i++) {
char c = line.charAt(i);
if (c == ',') {
resultArray[index] = number;
index++;
number = 0;
}
else if (Character.isDigit(c)) {
int digit = Character.getNumericValue(c);
number = number * 10 + digit;
}
}
if (index < resultArray.length) {
resultArray[index] = number;
}
}
public static int[] toArray(String line) {
int[] result = new int[countOccurrences(line, ',') + 1];
readToArray(line, result);
return result;
}
public static int countOccurrences(String haystack, char needle) {
int count = 0;
for (int i=0; i < haystack.length(); i++) {
if (haystack.charAt(i) == needle) {
count++;
}
}
return count;
}
countOccurrences implementation was shamelessly stolen from John Skeet

String arr= "[1,2]";
List<Integer> arrList= JSON.parseArray(arr,Integer.class).stream().collect(Collectors.toList());
Integer[] intArr = ArrayUtils.toObject(arrList.stream().mapToInt(Integer::intValue).toArray());