What is faster, Perl or Python?

Comparing the Speed of Perl and Python

When it comes to comparing the speed of Perl and Python, the short answer is: it depends. Both Perl and Python are high-level, interpreted scripting languages with strong communities and extensive libraries. But their performance can vary depending on the task, code style, and interpreter implementation.

Here are some key points to consider:

• Interpretation Speed: Perl's interpreter is traditionally known for fast text processing. Python 3, especially recent versions, has made major performance improvements but can still be slower than Perl in some string or regex-heavy tasks.
• Use Case: Perl excels in regular expressions and quick one-liners. Python often shines in larger applications, scientific computing, and where many optimized libraries are used.
• Version Differences: Newer versions of both languages improve speed. For Python, 3.7+ made optimizations. For Perl, 5.10+ introduced new opcodes enhancing speed.
• External Libraries: Both can use compiled C extensions to speed up bottlenecks.
• Microbenchmarks: Simple loop tests often show Perl to be slightly faster, but real-world differences depend heavily on tasks.
• Context and Implementation: Both languages have flexibility (TMTOWTDI - “There’s More Than One Way To Do It”). The efficiency of your approach probably impacts speed more than language choice.

Example Benchmark Code: Counting to One Million

Let’s demonstrate a simple loop that counts from 1 to 1,000,000 and sums the values. This basic test illustrates raw loop speed in Perl.

use strict;
use warnings;
use Time::HiRes qw(time);

# Measure time to sum numbers from 1 to 1,000,000
my $start = time();
my $sum = 0;
for my $i (1..1_000_000) {
    $sum += $i;
}
my $end = time();

printf "Sum is %d\n", $sum;
printf "Elapsed time: %.4f seconds\n", $end - $start;

Save this as sum.pl and run:

perl sum.pl

You can write an equivalent Python program like so (not shown here but easily comparable). Running both programs on the same hardware gives a rough indication of relative speed for this simple integer loop.

Perl-Specific Notes

• use strict; and use warnings; are best practices, helping avoid common errors.
• Perl's my declares lexically scoped variables. Sigils, like $, indicate scalar context here.
• Perl handles numeric and string context differently; make sure to keep calculations in numeric context for speed.

Common Pitfalls

• Microbenchmarks may not represent real-life performance. Focus on algorithm and profiling to optimize.
• Using inefficient data structures or unnecessary conversions can slow your code more than language overhead.
• Remember that startup time varies: Perl tends to start faster for small scripts.

Conclusion

In summary, Perl can be faster than Python in many shell scripting and text processing tasks, especially due to its optimized regex engine and interpreter design. Python’s speed is improving and excels in different domains with its extensive ecosystem.

For most practical applications, the choice between Perl and Python should consider developer productivity, available libraries, community support, and deployment environment rather than raw speed alone. When speed matters critically, profiling your code and using compiled extensions or alternative implementations (e.g., PyPy for Python, or XS modules for Perl) is key to achieving performance goals.