Helpful tips for usage of string

I don't think there is a need to explain the meaning of string. We can simply name it as a line and I would say that it is much better to use string than char (symbols) as there are more interesting tools and functions for it.

Let's start!

*1. Divide string

Indexof() brings the numeric value as it finds the first position of the entered symbol (or returns -1 if not found). So it can be used together with substring(), which cuts, to divide string and to keep the result also in string.

Example:

while (s.indexOf(' ') != -1)

{

int k = s.indexOf(' ');

s_devided+=s.substring(0,k);

s = s.substring(k + 1, s.length());

}

P.S. length() returns a numeric value (how much symbols does your line have)

*2. Divide string Pro

What if we divide string using some pattern? For example we want to spit the words. So we need a mass to keep all the words together.

String[] mas = new string [any length];

Then we have to use split() to delete all " "

Example:

String pattern = " ";

mas = line.split(pattern);

If our line="hello to all programmists", then we have mas[0]="Hello", mas[1]="to" and so on.

*3. Making copies carefully and correctly

Use System.arraycopy()

How to use it?

System.arraycopy(start mas1, first index mas1, result mas2, first index mas2, length);

*4. Num check

If you want to convert your string into a numeric value, you can catch a mistake if it is not a num, so you program will work incorrectly. Check with the function if it is a num and only then convert.

public static boolean isNumeric(String strNum) {

try {

long d = Long.parseLong(strNum);

}

catch (NumberFormatException | NullPointerException nfe) {

return false;

}

return true;

}

Other tools are simple for me in usage and don't need any explanation. If you have any questions, write to me anytime.

Good luck in your job!