珀尔 | Math::BigInt->length() 方法

珀尔 | Math::BigInt->length() 方法

Perl 中的Math::BigInt模块提供了表示具有任意精度和重载算术运算运算符的整数的对象。

Math::BigInt模块的length()方法用于获取给定数字的长度，即给定数字中的位数。

Syntax: Math::BigInt->length()

Parameter: None

Returns: an integer value which represents the length of the given number.

示例 1：使用Math::BigInt->length()方法计算数字中的位数

#!/usr/bin/perl 
  
# Import Math::BigInt module
use Math::BigInt;
  
# Specify number
$num = 78215936043546;
  
# Create BigInt object
$x = Math::BigInt->new($num);
  
# Get the length (or count of 
# digits) of the
# given number using
# Math::BigInt->length() method
$len = $x->length();
  
print "Length of $num is $len.\n";
  
# Specify another number
$num = 7821593604584625197;
  
# Create BigInt object
$x = Math::BigInt->new($num);
  
# Get the length (or count of 
# digits) of the
# given number using
# Math::BigInt->length() method
$len = $x->length();
  
print "Length of $num is $len.\n";

输出：

Length of 78215936043546 is 14.
Length of 7821593604584625197 is 19.

示例 2：使用Math::BigInt->length()方法将给定数字分成两半。

#!/usr/bin/perl 
  
# Import Math::BigInt module
use Math::BigInt;
  
# Specify number
$num = 78215936043546;
  
# Create BigInt object
$x = Math::BigInt->new($num);
  
# Get the length (or count of 
# digits) of the
# given number using
# Math::BigInt->length() method
$len = $x->length(); 
  
# Variable to store first half
$firstHalf = 0;
$i = 1;
  
# loop to calculate first half
while($i <= ($len/2))
{
    $firstHalf = ($firstHalf * 10) + 
                    $x->digit(-$i);
    $i = $i + 1;
      
}
  
# Variable to store second half
$secondHalf = 0;
  
# Loop to calculate second half
while($i <= $x->length())
{
    $secondHalf = ($secondHalf * 10) + 
                      $x->digit(-$i);
    $i = $i + 1;
}
  
# Note: Math::BigInt->digit() method
# returns the digit at ith position 
# from right end of the given number
# a negative value of i is used
# to get ith digit from left end 
# of the given number
  
# Print original number
print "Original number: $num\n";
  
# Print first half
print "First half: $firstHalf\n";
  
# Print Second half
print "Second half: $secondHalf";

输出：

Original number: 78215936043546
First half: 7821593
Second half: 6043546