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java regex questions [closed]

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Given that I have a string of number, like "12354789556", I need to check that string whether has digits from 0 to 9 at least once.
Can anyone tell me whether i can express this in regex please?

If your strings contains only digits for example "123548955664789556" then try:
System.out.println(myString.chars().distinct().count() == 10);
if your string can also contain letters for example sth like "bbb1235489556fhjerfs64789556"
System.out.println(myString.replaceAll("[^\\d]", "").chars().distinct().count() == 10);

With lookaheads :
^(?=.*0)(?=.*1)(?=.*2)(?=.*3)(?=.*4)(?=.*5)(?=.*6)(?=.*7)(?=.*8)(?=.*9)
If you want to restrict the string to digits only in addition to making sure it contains every digit :
^(?=.*0)(?=.*1)(?=.*2)(?=.*3)(?=.*4)(?=.*5)(?=.*6)(?=.*7)(?=.*8)(?=.*9)\d+$
Note that a version without lookaheads would be technically possible, but would realistically have to be crafted by code as it would have to enumerate all possible orders between digits (10! = 3628800 enumerations).

You can also do it in Java like this:
boolean containsAll = true;
for (int i = 0; i < 10; i++) {
if (!str.contains("" + i)) {
containsAll = false;
}
}
return containsAll;

A non-regex way would be to loop through the String and return false if the indexOf returns -1:
static boolean checkAll(String s, char[] allNums) {
for (int i = 0; i < allNums.length; i++) {
if (s.indexOf(allNums[i]) == -1) {
return false;
}
}
return true;
}
Example

Java Program, String [closed]

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It's about string to make a compact output.
Example 1
Input : boooooob
Output : bob
Example2
Input : boobaabbiibbuuuuub
Output : bobabibub
Can anyone help me?
I'm stuck, thx.

This can be solved by using regular expression (\\w)\\1+
public class RemoveReplicateLetter {
public static void main(String[] args) {
//For input: boooooob
System.out.println(removeReplicateLetter("boooooob"));
//For input: boobaabbiibbuuuuub
System.out.println(removeReplicateLetter("boobaabbiibbuuuuub"));
}
public static String removeReplicateLetter(String word) {
/*
REGEX:
(\\w)\\1+
- \\w : matches any word character (letter, digit, or underscore)
- \\1+ : matches whatever was in the first set of parentheses, one or more times.
*/
return word.replaceAll("(\\w)\\1+", "$1");
//Here $1 means return letter with match in word by regex.
}
}
Output:
bob
bobabibub

This method should do the job:
public String simplify(String input) {
// Convert to an array for char based comparison
char[] inputArray = input.toCharArray();
// First char will always be included in the output because there is no char to compete
String output = String.valueOf(inputArray[0]);
// Check every char against the following
for (int i = 1; i < inputArray.length; i++) {
// If not equal
if (inputArray[i - 1] != inputArray[i]) {
// Add to output
output += inputArray[i];
}
}
// Return the result
return output;
}
It will compare every char with the following one and only adds it to the output if they are not equal.
Note: This is just a proof of concept, not an optimal solution.

How do I create a loop which checks these values? [closed]

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If I had a numberical idno value, how would I find the ones >=5000 and < 5000? Would i use idno.substring(7,11) and then check the conditions
if >=5000 print Male
if <5000 print Female
How would I perform this?

Check idno % 10000 to get the value of the last four digits.
Given that your ID number is stored as an integer:
int idno = ...; // some ID number
You can use this comparison:
if (idno % 10000 >= 5000) {
System.out.println("Male");
} else {
System.out.println("Female");
}
The if statement is a branching operator that allows your code to branch to one block or another based on the result of the comparison. This is different from a loop.
A loop is code that will execute repeatedly until a condition is met. For example, if you had an array of integer ID numbers:
int[] idArray = { .... , .... , .... }; // some array of IDs
You could loop through them like this:
for (int idno: idArray) {
if (idno % 10000 >= 5000) {
System.out.println(idno+" is Male");
} else {
System.out.println(idno+" is Female");
}
}

First convert your String to integer using
int idno1=Integer.parseInt(idno);
Then simple check idno1<=5000 or idno1>5000

Any ways to find out "beautiful numbers" [closed]

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A beautiful number is a number containing only one type of digit, such as these: 0, 4, 44, 55555, 3333.
I would like to write an android app that finds out if a number is beautiful or not.

public static boolean isBeautiful(int n) {
char targetDigit = String.valueOf(n).toCharArray()[0];
for (char currentDigit : String.valueOf(n).toCharArray()) {
if (targetDigit != currentDigit) {
return false;
}
}
return true;
}
Bonus (sorry for the late addition of the bonus, but here it is), here's how to get all beautifuls up to x:
public static List<Integer> getBeautifuls(int upTo) {
List<Integer> beautifuls = new ArrayList<>();
int next = 0;
while (upTo >= next) {
beautifuls.add(next);
if (String.valueOf(next).toCharArray()[0] == '9') {
next = Integer.valueOf(new String(new char[String.valueOf(next).length() + 1]).replace("\0", "1"));
} else {
next = next + Integer.valueOf(new String(new char[String.valueOf(next).length()]).replace("\0", "1"));
}
}
return beautifuls;
}
Repeted string algorithm based on user102008's excellent answer on this question: Simple way to repeat a String in java
Note: Using Strings to create ints is a bit hack-ish and not so fast.

Try to check how many digits the number has, for example the number has 5 digits(between 10000-99999 and >= 11111)
if(num % 11111 == 0){
//it is beautiful number
}else{
//it is not beautiful
}
This is only an example for 5 digit numbers. You can develop an algorithm for checking other num of digits. I don't know is there any algorithm created before.

How do you assign a number in an array a value? [closed]

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I am trying to convert the tenth digit of an array to a number (10) if it is the value 'x'.
I have tried...
if (array[9] === 'x') {
'x' === 10;
};
Thanks

Try this, assuming that array is a char[]:
if (array[9] == 'x') {
array[9] = 10;
}
By the way, the code you posted is not valid for Java. This is not an operator: ===, we must use = for assignment and the trailing ; after the last } is unnecessary.

I edited your code already.
if (array[9] == 'x') //Line 1
{
array[9] = 10; // Line 2
}
On Line 1 you said ===. Java uses == to check if two primitive values are equal in value.
On Line 2 you used three equal signs again. If you want to reassign a variable, you will need to use ONE equal sign.