java test if a string is a int
public static boolean isInt(String str) {
try {
@SuppressWarnings("unused")
int x = Integer.parseInt(str);
return true; //String is an Integer
} catch (NumberFormatException e) {
return false; //String is not an Integer
}
}java how to check string is number
public static boolean isNumeric(String strNum) {
if (strNum == null) {
return false;
}
try {
double d = Double.parseDouble(strNum);
} catch (NumberFormatException nfe) {
return false;
}
return true;
}how to check if a string has only numbers in java
// Java program for the above approach
// contains only digits
class GFG {
// Function to check if a string
// contains only digits
public static boolean
onlyDigits(String str, int n)
{
// Traverse the string from
// start to end
for (int i = 0; i < n; i++) {
// Check if character is
// digit from 0-9
// then return true
// else false
if (str.charAt(i) >= '0'
&& str.charAt(i) <= '9') {
return true;
}
else {
return false;
}
}
return false;
}
// Driver Code
public static void main(String args[])
{
// Given string str
String str = "1234";
int len = str.length();
// Function Call
System.out.println(onlyDigits(str, len));
}
}check if string is decimal java
Scanner in = new Scanner(System.in);
String ip1 = in.nextLine();
if( ip1.matches("^\\d+\\.\\d+") )
System.out.println(ip1+"----is a decimal number");
else
System.out.println(ip1+"----is a not decimal number");how to check a number in string
To find whether a given string contains a number,
convert it to a character array and find whether
each character in the array is a digit using the isDigit()
method of the Character classcheck if the given string is a number
//Add this to your code and call
static private boolean isMyNumber(String s){
try{
Integer.parseInt(s);
return true;
}catch (Exception e){
return false;
}
}Copyright © 2021 Codeinu
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