is_numeric

The is_numeric() function allows you to check if a particular variable is a numeric string. Numeric strings can consist of a sign, any number of digits, a decimal part and an exponential part.

PHP

$my_string = '+1.998';
var_dump( is_numeric($string1) );
// => true

Ruby

def is_numeric?(num)
    true if Float(num) rescue false;
end
 
my_string = '+1.985';
puts is_numeric?(my_string);
# => true