Book Image

Mastering Julia - Second Edition

By : Malcolm Sherrington
Book Image

Mastering Julia - Second Edition

By: Malcolm Sherrington

Overview of this book

Julia is a well-constructed programming language which was designed for fast execution speed by using just-in-time LLVM compilation techniques, thus eliminating the classic problem of performing analysis in one language and translating it for performance in a second. This book is a primer on Julia’s approach to a wide variety of topics such as scientific computing, statistics, machine learning, simulation, graphics, and distributed computing. Starting off with a refresher on installing and running Julia on different platforms, you’ll quickly get to grips with the core concepts and delve into a discussion on how to use Julia with various code editors and interactive development environments (IDEs). As you progress, you’ll see how data works through simple statistics and analytics and discover Julia's speed, its real strength, which makes it particularly useful in highly intensive computing tasks. You’ll also and observe how Julia can cooperate with external processes to enhance graphics and data visualization. Finally, you will explore metaprogramming and learn how it adds great power to the language and establish networking and distributed computing with Julia. By the end of this book, you’ll be confident in using Julia as part of your existing skill set.
Table of Contents (14 chapters)

Using process I/O channels

To discuss using process I/O channels, we need to be in the Alice folder. Also in that folder is a rev.pl Perl script, whose function (as the name suggests) is to read its input stream, reverse the lines, and write them back to the output stream:

# For our example use the text of the Jabberwocky poem
julia> jabber = "jabberwocky.txt";
julia> proc = open(`./rev.pl $jabber`,"r+");
julia> proc.in
Base.PipeEndpoint(RawFD(26) open, 0 bytes waiting)
julia> close(proc.in);

We have closed the input stream, but the output is still open, so we can read the lines from it and display the reversed poem, not forgetting first to close the output stream too:

julia> poem = readlines(proc.out);
julia> close(proc.out);
julia> poem
34-element Vector{String}:
"sevot yhtils eht dna ,gillirb sawT'"
":ebaw eht ni elbmig dna eryg diD"
",sevogorob eht erew ysmim llA"
".ebargtuo shtar emom eht...