String s = "How are you?"
String[] a = s.split("\\s");
giving a = [How,are,you?]
further i want to split array a into sub array H,o,w
String[] b = a.split(""); // error here
This should work. As mentioned in the comments. a is not a string but an array. So you need to iterate over it to call the split() method on it's containing strings
String s = "How are you?"
String[] a = s.split("\\s");
for(String s2 : a){
String[] a2 = s2.split("");
// do your stuff with a2 in every iteration
}
try
"How".toCharArray() to get each letter or loop through
String str = "How";
for (int i = 0;i < str.length(); i++){
System.out.println(str.charAt(i));
}
You could also first remove all space chars and split afterwards.
String s = "How are you?";
String[] a = s.replaceAll("\\s","").split("");
System.out.println(Arrays.toString(a));
//[H, o, w, a, r, e, y, o, u, ?]
You can get character stream and print each character individually, e.g.:
String s = "How are you";
s.chars()
.forEach(c -> System.out.println((char)c));
Related
So my issue here is that I am trying to take in a String from user input, but then I need to convert that string into an array.
So as an example, the user inputted string would be "Hello", and the array (named arr) would be: arr[0]="H" arr[1] = "e" and so on. If anyone can point me in the right direction I would appreciate it a lot!
Use the standard library method:
char[] arr = str.toCharArray();
Documentation: java.lang.String.toCharArray()
There's a built in function to convert a string to a character array:
String myString = ...;
char[] chars = myString.toCharArray();
If you need each character as a stirng, you can loop over the character array and convert it:
String myString = ...;
String[] result = new String[myString.length];
char[] chars = myString.toCharArray();
for (int i = 0; i < chars.length; ++i) {
result[i] = String.valueOf(chars[i]);
}
Read javadoc:
String - toCharArray method
public char[] toCharArray()
Converts this string to a new character array.
String hello = "Hello";
String[] array = hello.split("");
You can use String.split("") like
String[] arr = str.split("");
That will give you an array arr where each substring is one character
[H, e, l, l, o]
Another option might be String.toCharArray() if a char[] is acceptable like
char[] arr = str.toCharArray();
I am trying to separate the char from the following examples of inputs:
C450.00
C30
P100
I would like to have the char such as "C" or "P" separated so I can work with them alone,
as well as the "450.00", "30", and "100" separated as ints. What would be the easiest way to do this?
You can split the String with whitespace as delimiter. Afterwards use substring on every part of your string. Now you have the C and the 450.0 as Stings. Finally cast the second part of your substring into an integer and you are done.
to split:
String[] parts = string.split(" ");
to substring:
String first = parts[0].substring(0, 1);
String second = parts[0].substring(1);
If the String are always that format:
char ch = yourString.charAt(0);
Double d = Double.valueOf(yourString.substring(1, yourString.length()));
NOTE: I used a Double because you have dots . in the String. You can convert from double to int easily if you won't have any decimals. But that depends on your needings.
Assuming you know what are you looking for in the given String (eg. You know you are looking for the C character ) , you could use the Regex Pattern : https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html
You can use this library org.apache.commons.lang3.StringUtils
http://commons.apache.org/proper/commons-lang/download_lang.cgi
public static String[] split(String str, String separatorChars)
String[] res = StringUtils.split("C450.00 C30 P100", "CP ");
for (String r : res) {
System.out.println(r);
}
I assume the separate 'numbers' are always in this format:
C130
P90
V2.0
that is, a single letter followed by a number (possibly with a floating point).
String input = "C450.00 C30 P100";
// First split the string by a space
String[] parts = input.split(" ");
for (String part : parts) {
// Get the character from the string
char ch = part.charAt(0);
// Get the remains of the string and convert it to a double
double number = Double.parseDouble(part.substring(1));
// Then do something with 'ch' and 'number'
}
If the separate parts possibly have two or more letters in it, e.g. AC130, then you need another approach:
String input = "AC130 AG36 P90";
String[] parts = input.split(" ");
for (String part : parts) {
/* Do some regular expression magic. */
}
See http://www.vogella.com/tutorials/JavaRegularExpressions/article.html.
here some piece of code:
public static void main(String[] args) {
String a = "C450.00 C30 P100";
String letters = "";
String numbers = "";
for (int i = 0; i < a.length(); i++) {
if ((a.charAt(i) + "").matches("\\d|\\.| ")) {
numbers += a.charAt(i);
} else {
letters += a.charAt(i);
}
}
String[] strArray = numbers.split(" ");
int[] numberArray = new int[strArray.length];
for (int i = 0; i < strArray.length; i++) {
numberArray[i] = (int) Double.parseDouble(strArray[i]);
System.out.println(numberArray[i]);
}
System.out.println(letters);
}
the result is numberArray, which contains all numbers as ints.
and letters, which is a String with all letters.
I'm extremely stuck here.
How would I convert a String array to a Char array?
I know of:
char[] myCharArray = myStringArray.toCharArray();
But obviously that doesn't work.
How would I do this?
You need to use a 2d/jagged array.
char[][] char2dArray = new char[myStringArray.length()][];
for ( int i=0; i < myStringArray.length(); i++) {
char2dArray[i] = myStringArray[i].toCharArray();
}
Here's one way to grab all the chars from all the strings in a single char array, if that's what you meant with the question:
String[] strArray = {"ab", "cd", "ef"};
int count = 0;
for (String str : strArray) {
count += str.length();
}
char[] charArray = new char[count];
int i = 0;
for (String str : strArray) {
for (char c : str.toCharArray()) {
charArray[i++] = c;
}
}
System.out.println(Arrays.toString(charArray));
=> [a, b, c, d, e, f]
You need to iterate through your String array converting every string in the string array to a char and then add that new char to your char array.
Assuming that a myStringArray is an array of Strings you would have to first iterate through this array extracting each individual String before converting the String to an array of chars.
for example
for (String str : myStringArray) {
{
char[] myCharArray = myStringArray.toCharArray();
// do something with myCharArray
}
I've been trying to split an string by a character and store each split value inside an array.
In C# it can be done by calling the .ToArray() method after the Split() but such method apparently doesn't exits in Java. So I've been trying to do this like this (rs is a string list with elements separated by #) :
String t[] = new String[10];
for (int i = 0; i < rs.size(); i++) {
t = null;
t = rs.get(i).split("#");
}
But the whole split line is passed to an index of the array like:
String x = "Hello#World" -> t[0] = "Hello World" (The string is split in one line, so the array will have only one index of 0)
My question is that how can store each spit element in an index of the array like :
t[0] = "Hello"
t[1] = "World"
It sounds like your trying to loop through a list, split them then add the arrays together? What your defining as the problem with the .split method is exactly what the split method does.
ArrayList<String> rs = new ArrayList<>();
rs.add("Hello#World");
rs.add("Foo#Bar#Beckom");
String [] t = new String[0];
for(int i=0;i<rs.size();i++) {
String [] newT = rs.get(i).split("#");
String [] result = new String[newT.length+t.length];
System.arraycopy(t, 0, result, 0, t.length);
System.arraycopy(newT, 0, result, t.length, newT.length);
t = result;
}
for(int i=0;i<t.length;i++) {
System.out.println(t[i]);
}
Works just find output is:
Hello
World
Foo
Bar
Beckom
public class Test {
public static void main(String[] args) {
String hw = "Hello#World";
String[] splitHW = hw.split("#");
for(String s: splitHW){
System.out.println(s);
}
}
}
This produced following output for me:
Hello
World
Try this way:
String string = "Hello#World"
String[] parts = string.split("#");
String part1 = parts[0]; // Hello
String part2 = parts[1]; // World
It is always good to test beforehand if the string contains a #(in this case), just use String#contains().
if (string.contains("#")) {
// Split it.
} else {
throw new IllegalArgumentException(message);
}
why are you using a loop when the problem is already solved in java..
try this
String x = "Hello#World";
String[] array = x.split("#", -1);
System.out.println(array[0]+" "+array[1]);
I want to convert a String to an array of objects of Character class but I am unable to perform the conversion. I know that I can convert a String to an array of primitive datatype type "char" with the toCharArray() method but it doesn't help in converting a String to an array of objects of Character type.
How would I go about doing so?
Use this:
String str = "testString";
char[] charArray = str.toCharArray();
Character[] charObjectArray = ArrayUtils.toObject(charArray);
One liner with java-8:
String str = "testString";
//[t, e, s, t, S, t, r, i, n, g]
Character[] charObjectArray =
str.chars().mapToObj(c -> (char)c).toArray(Character[]::new);
What it does is:
get an IntStream of the characters (you may want to also look at codePoints())
map each 'character' value to Character (you need to cast to actually say that its really a char, and then Java will box it automatically to Character)
get the resulting array by calling toArray()
Why not write a little method yourself
public Character[] toCharacterArray( String s ) {
if ( s == null ) {
return null;
}
int len = s.length();
Character[] array = new Character[len];
for (int i = 0; i < len ; i++) {
/*
Character(char) is deprecated since Java SE 9 & JDK 9
Link: https://docs.oracle.com/javase/9/docs/api/java/lang/Character.html
array[i] = new Character(s.charAt(i));
*/
array[i] = s.charAt(i);
}
return array;
}
Converting String to Character Array and then Converting Character array back to String
//Givent String
String given = "asdcbsdcagfsdbgdfanfghbsfdab";
//Converting String to Character Array(It's an inbuild method of a String)
char[] characterArray = given.toCharArray();
//returns = [a, s, d, c, b, s, d, c, a, g, f, s, d, b, g, d, f, a, n, f, g, h, b, s, f, d, a, b]
//ONE WAY : Converting back Character array to String
int length = Arrays.toString(characterArray).replaceAll("[, ]","").length();
//First Way to get the string back
Arrays.toString(characterArray).replaceAll("[, ]","").substring(1,length-1)
//returns asdcbsdcagfsdbgdfanfghbsfdab
or
// Second way to get the string back
Arrays.toString(characterArray).replaceAll("[, ]","").replace("[","").replace("]",""))
//returns asdcbsdcagfsdbgdfanfghbsfdab
//Second WAY : Converting back Character array to String
String.valueOf(characterArray);
//Third WAY : Converting back Character array to String
Arrays.stream(characterArray)
.mapToObj(i -> (char)i)
.collect(Collectors.joining());
Converting string to Character Array
Character[] charObjectArray =
givenString.chars().
mapToObj(c -> (char)c).
toArray(Character[]::new);
Converting char array to Character Array
String givenString = "MyNameIsArpan";
char[] givenchararray = givenString.toCharArray();
String.valueOf(givenchararray).chars().mapToObj(c ->
(char)c).toArray(Character[]::new);
benefits of Converting char Array to Character Array you can use the Arrays.stream funtion to get the sub array
String subStringFromCharacterArray =
Arrays.stream(charObjectArray,2,6).
map(String::valueOf).
collect(Collectors.joining());
String#toCharArray returns an array of char, what you have is an array of Character. In most cases it doesn't matter if you use char or Character as there is autoboxing. The problem in your case is that arrays are not autoboxed, I suggest you use an array of char (char[]).
You have to write your own method in this case. Use a loop and get each character using charAt(i) and set it to your Character[] array using arrayname[i] = string.charAt[i].
I hope the code below will help you.
String s="Welcome to Java Programming";
char arr[]=s.toCharArray();
for(int i=0;i<arr.length;i++){
System.out.println("Data at ["+i+"]="+arr[i]);
}
It's working and the output is:
Data at [0]=W
Data at [1]=e
Data at [2]=l
Data at [3]=c
Data at [4]=o
Data at [5]=m
Data at [6]=e
Data at [7]=
Data at [8]=t
Data at [9]=o
Data at [10]=
Data at [11]=J
Data at [12]=a
Data at [13]=v
Data at [14]=a
Data at [15]=
Data at [16]=P
Data at [17]=r
Data at [18]=o
Data at [19]=g
Data at [20]=r
Data at [21]=a
Data at [22]=m
Data at [23]=m
Data at [24]=i
Data at [25]=n
Data at [26]=g
another way to do it.
String str="I am a good boy";
char[] chars=str.toCharArray();
Character[] characters=new Character[chars.length];
for (int i = 0; i < chars.length; i++) {
characters[i]=chars[i];
System.out.println(chars[i]);
}
This method take String as a argument and return the Character Array
/**
* #param sourceString
* :String as argument
* #return CharcterArray
*/
public static Character[] toCharacterArray(String sourceString) {
char[] charArrays = new char[sourceString.length()];
charArrays = sourceString.toCharArray();
Character[] characterArray = new Character[charArrays.length];
for (int i = 0; i < charArrays.length; i++) {
characterArray[i] = charArrays[i];
}
return characterArray;
}
if you are working with JTextField then it can be helpfull..
public JTextField display;
String number=e.getActionCommand();
display.setText(display.getText()+number);
ch=number.toCharArray();
for( int i=0; i<ch.length; i++)
System.out.println("in array a1= "+ch[i]);
chaining is always best :D
String str = "somethingPutHere";
Character[] c = ArrayUtils.toObject(str.toCharArray());
If you don't want to rely on third party API's, here is a working code for JDK7 or below. I am not instantiating temporary Character Objects as done by other solutions above. foreach loops are more readable, see yourself :)
public static Character[] convertStringToCharacterArray(String str) {
if (str == null || str.isEmpty()) {
return null;
}
char[] c = str.toCharArray();
final int len = c.length;
int counter = 0;
final Character[] result = new Character[len];
while (len > counter) {
for (char ch : c) {
result[counter++] = ch;
}
}
return result;
}
I used the StringReader class in java.io. One of it's functions read(char[] cbuf) reads a string's contents into an array.
String str = "hello";
char[] array = new char[str.length()];
StringReader read = new StringReader(str);
try {
read.read(array); //Reads string into the array. Throws IOException
} catch (IOException e) {
e.printStackTrace();
}
for (int i = 0; i < str.length(); i++) {
System.out.println("array["+i+"] = "+array[i]);
}
Running this gives you the output:
array[0] = h
array[1] = e
array[2] = l
array[3] = l
array[4] = o
String[] arr = { "abc", "cba", "dac", "cda" };
Map<Character, Integer> map = new HashMap<>();
String string = new String();
for (String a : arr) {
string = string.concat(a);
}
System.out.println(string);
for (int i = 0; i < string.length(); i++) {
if (map.containsKey(string.charAt(i))) {
map.put(string.charAt(i), map.get(string.charAt(i)) + 1);
} else {
map.put(string.charAt(i), 1);
}
}
System.out.println(map);
//out put {a=4, b=2, c=4, d=2}