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!