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I cannot print value of converted string

I want to reverse a string. I know there are some other methods to do it but I wanted to do in a different way. There is no error but no output when I run my code. I dont understand why "String.valueOf(word.charAt(i)" doesnt return a value? Am I missing something?
String word = "myword";
for (int i = word.length(); i <= 0; i--) {
System.out.print(String.valueOf(word.charAt(i)));
}

The first value of i is out of index. And I also fixed your code. Check below:
String word = "myword";
for(int i=word.length()-1;i>=0;i--){
System.out.print(String.valueOf(word.charAt(i)));}

Just for providing another slightly different solution:
You can use a StringBuilder to reverse a String using its method reverse().
If you have a String, you can use it to initialize the StringBuilder with it and directly reverse it.
This example additionally uses an enhanced for-loop, which always goes through all of the elements. Using that, you can get rid of checking the length of a String and you won't have to use an int i for iterating.
For your requirements, this is a suitable option because you want to reverse the whole String.
String word = "myword";
for (char c : new StringBuilder(word).reverse().toString().toCharArray()) {
System.out.println(c);
}
Note that you can use the reverse() method for printing the reversed word in one line just doing
System.out.println(new StringBuilder(word).reverse().toString());

Your code has 2 issues.
i should be initialized with word.length()-1. Other wise you will get StringIndexOutOfBoundsException
for loop condition should be >= 0.
Below is the corrected code.
String word = "myword";
for(int i=word.length()-1;i>=0;i--) {
System.out.print(word.charAt(i));
}

Error in swapping characters in stringbuffer object

i am trying to sort a string in the alphabetical order, however i am facing an error in the line :
sb.charAt(j)=sb.charAt(j+1);
where the compiler shows an error as expected variable; found value
the rest of the code is as follows :
import java.util.Scanner;
class a
{
public static void main(String[] agrs)
{
Scanner sc = new Scanner(System.in);
String s = sc.next();
StringBuffer sb = new StringBuffer();
sb.append(s);
for(int i = 0; i< s.length(); i++)
{
for(int j = 0; j<s.length(); j++)
{
if(s.charAt(j)>s.charAt(j+1)){
char temp = s.charAt(j);
sb.charAt(j)=sb.charAt(j+1);
sb.charAt(j+1)=temp;
}
}
}}}
kindly help me out as i'm a beginner and i cannot figure out why this issue is occurring , thank you .

This looks like a homework assignment where the goal is to sort the characters of a text being entered, so if you enter gfedbca the result should be abcdefg.
You already got a comment telling you what the problem is: StringBuffer#charAt() is not returning a reference to StringBuffer's internal array that you can change the value of. Dependent on the actual assignment you can call StringBuffers setCharAt method or you can go another approach by converting the text to sort to a char array and do the sorting in there. There are actually helper-classes in the JVM, that do that for you, have a look e.g. at the class java.util.Arrays

As already answered by many, the issue is in charAt(index) you are using, as this returns the character at the given index rather than setting a char at the index position.
My answer is to divert your approach of sorting. For simpler solutions, where smaller data sets (like your problem) are used, you should use the predefined sorting algorithms, like Insertion Sort
You may get help for the algo from here: http://www.geeksforgeeks.org/insertion-sort/

StringBuffer's charAt returns just the value of the char at the index, if you want to swap two chars you need to use setter for that, so you possible want to do somtehing like:
for(int j = 0; j < s.length() - 1; j++) {
if(s.charAt(j) > s.charAt(j + 1)) {
char temp = s.charAt(j);
sb.setCharAt(j, sb.charAt(j + 1));
sb.setCharAt(j + 1, temp);
}
}

This method can only return values and can not set values, I guess you might want to use this method:
setCharAt()
It can meet your requirement

How do I access and manipulate individual values in a String Array when using a while and for loop

Very new to Java: Trying to learn it.
I created an Array and would like to access individual components of the array.
The first issue I am having is how to I print the array as a batch or the whole array as indicated below? For example: on the last value MyValue4 I added a line break so that when the values are printed, the output will look like this: There has to be a better way to do this?
MyValue1
MyValue2
MyValue3
MyValue4
MyValue1
MyValue2
MyValue3
MyValue4
The next thing I need to do is, manipulate or replace a value with something else, example: MyValue with MyValx, when the repeat variable is at a certain number or value.
So when the repeat variable reaches 3 change my value to something else and then change back when it reaches 6.
I am familiar with the Replace method, I am just not sure how to put this all together.
I am having trouble with changing just parts of the array with the while and for loop in the mix.
My Code:
public static String[] MyArray() {
String MyValues[] = { "MyValue1", "MyValue2", "MyValue3", "MyValue4\n" };
return MyValues;
}
public static void main(String[] args) {
int repeat = 0;
while (repeat < 7) {
for (String lines : MyArray()) {
System.out.println(lines);
}
repeat = repeat + 1;
if (repeat == 7) {
break;
}
}
}

Maybe to use for cycle to be shorter:
for (int i = 0; i < 7; i++) {
for (String lines : MyArray()) {
// Changes depended by values.
if (i > 3) {
lines = MyValx;
}
System.out.println(lines); // to have `\n` effect
}
System.out.println();
}
And BTW variables will start in lower case and not end withenter (\n). So use:
String myValues[] = {"MyValue1", "MyValue2", "MyValue3", "MyValue4"};
instead of:
String MyValues[] = { "MyValue1", "MyValue2", "MyValue3", "MyValue4\n" };
and add System.out.println(); after eache inside cycle instead of this:

MyValues[n] = "value";
where n is the position in the array.

You may consider using System.out.println() without any argument for printing an empty line instead of inserting new-line characters in your data.
You already know the for-each loop, but consider a count-controlled loop, such as
for (int i = 0; i < lines.length; i++) {
...
}
There you can use i for accessing your array as well as for deciding for further actions.
Replacing array items based on a number in a string might be a bit trickier. A regular expression will definitely do the job, if you are familiar with that. If not, I can recommend learning this, because it will sure be useful in future situations.
A simpler approach might be using
int a = Integer.parseInt("123"); // returns 123 as integer
but that only works on strings, which contain pure numbers (positive and negative). It won't work with abc123. This will throw an exception.
These are some ideas, you might try out and experiment with. Also use the documentation excessively. ;-)

How to look for a target in an array using two string array's

So in looking around for an answer to my question, i have only been able to find map structures or just comparing the strings and having to code to stop. I need to be able to essentially translate between languages and print out the translation and have the user to able to ask again to translate another word. I have 2 strings of 10 matching words from English to Russian. I need to able to use a target (or key) to find the translation. Also I need to use a sequential search.
import java.util.*;
public class CISCLabTwo
{
public static void main (String [] args)
{
Scanner keyBoard = new Scanner (System.in);
String [] english = {"House", "Fat", "Monkey", "Trip", "Jumbo", "Chicken", "Unicorn", "Radio", "Shack", "Xylophone"};
String [] russian = {"Dom", "Zhir", "Obeziana", "Poezdka", "Ogromniy", "Kuricha", "Edinorog", "Raadiioo", "Hizhina", "Ksilofon"};
System.out.println ("House, Fat, Monkey, Trip, Jumbo, Chicken, Unicorn, Radio, Shack, Xylophone");
System.out.println("Enter a Word From Above to Translate to Russian: ");
int i = 0;
for (i = 0; i < english.length; i++)
if (english[i]=target){
return i;
}
else{
return - 1;
}
}//end class
public static int translate (String [] english, String target)
}//end main

http://en.wikipedia.org/wiki/Sequential_search
Basically you create a for-loop checking for a match in the english array.
When you have a match the function will return the position of the string in the given array. Use this position to get the corresponding Russian translation.
public static int translate(String [] english, String target)
{
for(int i = 0; i < english.length; i++){
if(english[i].equals(target)){
// Found on position i
return i;
}
}
return -1;
}
You might want to rename the function because it doesn't really translate and only returns an integer and not a string.

Firstly, it's confusing to individually handle two arrays in this way. You probably want to create an extra class in the same file:
class Word {
String english;
String russian;
}
Then you can create the following array:
Word[] words = new Word[10];
That way, you can translate using a separate method, as follows:
String translate(String eng) {
for (Word w : words) if (eng.equals(w.english)) return w.russian;
return null;
}

All you need to do is get the index, print the Russian word then break the loop.
If just printing within main then you can do this.
for (i = 0; i < english.length; i++)
{
if (english[i].equals(target))
{
System.out.println(russian[i]; //Print the russian word
break; //stop looping
}
}
Otherwise if you want to have your translate method that returns the index of the word you could do it like so
public static int translate (String [] english, String target)
{
for (i = 0; i < english.length; i++)
{
if (english[i].equals(target))
return i; // No need for the else statement as it would
// fail on first iteration if it wasnt the word
}
return -1; // After loop exits return -1 as was not found
}
Then in main you would call
String russianWord = russian[translate(english, target)];

As for your code, the proper check is in your for-next loop is
if (english[i].equals(target))
return i;
Also, consider whether the case of the words matters. In your example, is "House" the same as "house"? If case doesn't matter, you should use equalsIgnoreCase() instead of equals, i.e.
if (english[i].equalsIgnoreCase(target))
return i;
(moved later cause it seems like this was homework)
You could save yourself a little work by using two ArrayList to hold the words, since ArrayList has an indexOf() method to do the linear search. (I have no idea why the Arrays utility class does not have an indexOf method).
That said, a map based structure seems like a much better fit (and will be more efficient).

Determining if a given string of words has words greater than 5 letters long

So, I'm in need of help on my homework assignment. Here's the question:
Write a static method, getBigWords, that gets a String parameter and returns an array whose elements are the words in the parameter that contain more than 5 letters. (A word is defined as a contiguous sequence of letters.) So, given a String like "There are 87,000,000 people in Canada", getBigWords would return an array of two elements, "people" and "Canada".
What I have so far:
public static getBigWords(String sentence)
{
String[] a = new String;
String[] split = sentence.split("\\s");
for(int i = 0; i < split.length; i++)
{
if(split[i].length => 5)
{
a.add(split[i]);
}
}
return a;
}
I don't want an answer, just a means to guide me in the right direction. I'm a novice at programming, so it's difficult for me to figure out what exactly I'm doing wrong.
EDIT:
I've now modified my method to:
public static String[] getBigWords(String sentence)
{
ArrayList<String> result = new ArrayList<String>();
String[] split = sentence.split("\\s+");
for(int i = 0; i < split.length; i++)
{
if(split[i].length() > 5)
{
if(split[i].matches("[a-zA-Z]+"))
{
result.add(split[i]);
}
}
}
return result.toArray(new String[0]);
}
It prints out the results I want, but the online software I use to turn in the assignment, still says I'm doing something wrong. More specifically, it states:
Edith de Stance states:
⇒     You might want to use: +=
⇒     You might want to use: ==
⇒     You might want to use: +
not really sure what that means....

The main problem is that you can't have an array that makes itself bigger as you add elements.
You have 2 options:
ArrayList (basically a variable-length array).
Make an array guaranteed to be bigger.
Also, some notes:
The definition of an array needs to look like:
int size = ...; // V- note the square brackets here
String[] a = new String[size];
Arrays don't have an add method, you need to keep track of the index yourself.
You're currently only splitting on spaces, so 87,000,000 will also match. You could validate the string manually to ensure it consists of only letters.
It's >=, not =>.
I believe the function needs to return an array:
public static String[] getBigWords(String sentence)
It actually needs to return something:
return result.toArray(new String[0]);
rather than
return null;
The "You might want to use" suggestions points to that you might have to process the array character by character.

First, try and print out all the elements in your split array. Remember, you do only want you look at words. So, examine if this is the case by printing out each element of the split array inside your for loop. (I'm suspecting you will get a false positive at the moment)
Also, you need to revisit your books on arrays in Java. You can not dynamically add elements to an array. So, you will need a different data structure to be able to use an add() method. An ArrayList of Strings would help you here.

split your string on bases of white space, it will return an array. You can check the length of each word by iterating on that array.
you can split string though this way myString.split("\\s+");

Try this...
public static String[] getBigWords(String sentence)
{
java.util.ArrayList<String> result = new java.util.ArrayList<String>();
String[] split = sentence.split("\\s+");
for(int i = 0; i < split.length; i++)
{
if(split[i].length() > 5)
{
if(split[i].matches("[a-zA-Z]+"))
{
result.add(split[i]);
}
if (split[i].matches("[a-zA-Z]+,"))
{
String temp = "";
for(int j = 0; j < split[i].length(); j++)
{
if((split[i].charAt(j))!=((char)','))
{
temp += split[i].charAt(j);
//System.out.print(split[i].charAt(j) + "|");
}
}
result.add(temp);
}
}
}
return result.toArray(new String[0]);
}

Whet you have done is correct but you can't you add method in array. You should set like a[position]= spilt[i]; if you want to ignore number then check by Float.isNumber() method.

Your logic is valid, but you have some syntax issues. If you are not using an IDE like Eclipse that shows you syntax errors, try commenting out lines to pinpoint which ones are syntactically incorrect. I want to also tell you that once an array is created its length cannot change. Hopefully that sets you off in the right directions.

Apart from syntax errors at String array declaration should be like new String[n]
and add method will not be there in Array hence you should use like
a[i] = split[i];
You need to add another condition along with length condition to check that the given word have all letters this can be done in 2 ways
first way is to use Character.isLetter() method and second way is create regular expression
to check string have only letter. google it for regular expression and use matcher to match like the below
Pattern pattern=Pattern.compile();
Matcher matcher=pattern.matcher();
Final point is use another counter (let say j=0) to store output values and increment this counter as and when you store string in the array.
a[j++] = split[i];

I would use a string tokenizer (string tokenizer class in java)
Iterate through each entry and if the string length is more than 4 (or whatever you need) add to the array you are returning.
You said no code, so... (This is like 5 lines of code)