Perl | Automatic String to Number Conversion or Casting

Typecasting

• Implicit Typecasting: Implicit type conversion is done by the compiler itself. There is no need for the user to mention a specific type conversion using any method. The compiler on its own determines the data type of the variable if required and fixes it. In Perl when we declare a new variable and assign a value to it, it automatically converts it into a required data type. Example 1: Perl

  # Perl code to demonstrate implicit 
  # type casting
  
  # variable x is of int type
  $x = 57;
  
  # variable y is of int type
  $y = 13;
  
  # z is an integer data type which
  # will contain the sum of x and y
  # implicit or automatic conversion
  $z = $x + $y;
  
  print "z is ${z}\n";
  
  # type conversion of x and y integer to 
  # string due to concatenate function
  $w = $x.$y;
  
  # w is a string which has the value: 
  # concatenation of string x and string y
  print "w is ${w}\n";
  

  Output:

  z is 70
  w is 5713
  

• Explicit Typecasting: In this conversion the user can cast a variable to a particular data type according to requirement. Explicit type conversion is required if the programmer wants a particular variable to be of a particular data type. It is important for keeping the code consistent so that no variable causes an error due to type conversion. Example: The following perform explicit typecasting where a string(or any data type) is converted to specified type(say int). Perl

  # Perl code to demonstrate Explicit 
  # type casting
  
  # String type
  $string1 = "27";
  
  # conversion of string to int 
  # using typecasting int()
  $num1 = int($string1);
  
  $string2 = "13";
  
  # conversion of string to int
  # using typecasting int()
  $num2 = int($string2);
  
  print "Numbers are $num1 and $num2\n";
  
  # applying arithmetic operators 
  # on int variables 
  $sum = $num1 + $num2;
  
  print"Sum of the numbers = $sum\n";
  

  Output:

  Numbers are 27 and 13
  Sum of the numbers = 40
  

sprintf function

# Perl code to demonstrate the use 
# of sprintf function

# string type
$string1 = "25";

# using sprintf to convert 
# the string to integer
$num1 = sprintf("%d", $string1);

$string2 = "13";

# using sprintf to convert 
# the string to integer
$num2 = sprintf("%d", $string2);

# applying arithmetic operators
# on int variables 
print "Numbers are $num1 and $num2\n";

$sum = $num1 + $num2;
print"Sum of the numbers = $sum\n";

Numbers are 25 and 13
Sum of the numbers = 38