how to check if a string contains numbers in java code example
Example 1: 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));
}
}
Example 2: 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 class