In java how to get substring from a string till a character c?

Question

I have a string (which is basically a file name following a naming convention) abc.def.ghi

I would like to extract the substring before the first

Answer 1

look at String.indexOf and String.substring.

Make sure you check for -1 for indexOf.

Answer 2

Here is code which returns a substring from a String until any of a given list of characters:

/**
 * Return a substring of the given original string until the first appearance
 * of any of the given characters.
 * <p>
 * e.g. Original "ab&cd-ef&gh"
 * 1. Separators {'&', '-'}
 * Result: "ab"
 * 2. Separators {'~', '-'}
 * Result: "ab&cd"
 * 3. Separators {'~', '='}
 * Result: "ab&cd-ef&gh"
 *
 * @param original   the original string
 * @param characters the separators until the substring to be considered
 * @return the substring or the original string of no separator exists
 */
public static String substringFirstOf(String original, List<Character> characters) {
    return characters.stream()
            .map(original::indexOf)
            .filter(min -> min > 0)
            .reduce(Integer::min)
            .map(position -> original.substring(0, position))
            .orElse(original);
}

Answer 3

The accepted answer is correct but it doesn't tell you how to use it. This is how you use indexOf and substring functions together.

String filename = "abc.def.ghi";     // full file name
int iend = filename.indexOf("."); //this finds the first occurrence of "." 
//in string thus giving you the index of where it is in the string

// Now iend can be -1, if lets say the string had no "." at all in it i.e. no "." is found. 
//So check and account for it.

String subString;
if (iend != -1) 
{
    subString= filename.substring(0 , iend); //this will give abc
}

Answer 4

How about using regex?

String firstWord = filename.replaceAll("\\..*","")

This replaces everything from the first dot to the end with "" (ie it clears it, leaving you with what you want)

Here's a test:

System.out.println("abc.def.hij".replaceAll("\\..*", "");

Output:

abc

Answer 5

This could help:

public static String getCorporateID(String fileName) {

    String corporateId = null;

    try {
        corporateId = fileName.substring(0, fileName.indexOf("_"));
        // System.out.println(new Date() + ": " + "Corporate:
        // "+corporateId);
        return corporateId;
    } catch (Exception e) {
        corporateId = null;
        e.printStackTrace();
    }

    return corporateId;
}

Answer 6

In java.lang.String you get some methods like indexOf(): which returns you first index of a char/string. and lstIndexOf: which returns you the last index of String/char

From Java Doc:

  public int indexOf(int ch)
  public int indexOf(String str)

Returns the index within this string of the first occurrence of the specified character.