If you plan to count files in current directory in Julia, you can just run following code:
files_and_dirs = readdir(pwd()) # reading files and directory
function count()
global num =0
for i in files_and_dirs
if isfile(i)
num +=1
end
end
end
count()
println(num)
Working with files in every programming language is almost everyday routine. While writing scripts and programs in Julia, sometimes we need to choose files with certain extension. Julia offers very simple, fast and powerful tools for operation with strings.
In order to get (or print) file's extension in Julia, we don't even need to use regular expressions (which surely will took time to learn). Another question is, that not all files have extensions. In this case we have nothing to do, because in this case file's extension will be an empty string. Next question is files with complex extensions, for example .tar.gz. We are not going to solve those types, because I cannot imagine a situation, when there's need to change .tar.gz extension. That's why, let's focus in files, which have most common extensions (1,2,3,4 - characters), for example: .c , .sh or .zip.
In our example we will combine several string operations to get the final result.
Technique is very simple:
julia> filename = "the_most_interesting_movie_ever.avi"
julia> findlast(isequal('.'),filename)
32
No we know, that dot has the 32-nd position in a string "the_most_interesting_movie_ever.avi"
Create a file "shortest_filename.jl" and put following code into it:
files = readdir(pwd())
info = Dict{String,Integer}()
println("The shortest filename has length: ",minimum(values(info)))
List of files:
$ bookings count_files.jl libs list_only_files.jl
books.txt hello-world.jl list_only_dirs.jl show_longest_filename.jl
$ julia show_longest_filename.jl
The shortest filename has length: 4
First of all, let's get a list of all filenames in current directory:
files = readdir(pwd())
Then let's make a Dictionary with filename as a key and length of the filename as a value:
info = Dict{String,Integer}()
for (n,f) in enumerate(files)
info["$(f)"] = length(f)
end
And now we can list filenames sorted alphabetically with a length of filename in brackets:
for key in sort(collect(keys(info)))
println("$key ($(info[key]))")
end
Result:
bookings (8)
books.txt (9)
count_files.jl (14)
hello-world.jl (14)
libs (4)
list_only_dirs.jl (17)
list_only_files.jl (18)
show_longest_filename.jl (24)
To list files in current directory and exclude counting directories (sub-directories) in current folder we just use readdir() function and then we count only files.
Let's see, what we have in a directory (files and directories):
$ ls
output:
dima@linux-zsrx:~/julia> ls
bookings hello-world.jl
books.txt libs
count_files.jl list_only_files.jl
You see, that we have two directories ("libs" and "bookings") and the rest are files. Our goal is to list only those two directories (de facto: only subdirectories/sub-folders) and exclude files. Let's create a file with the name list_only_dirs.jl in order to use it in every directory in our system, and put following code into it:
To list files in current directory and exclude counting directories (sub-directories) in current folder we just use readdir() function and then we count only files.
Let's see, what we have in a directory (files and directories):
$ ls
output:
dima@linux-zsrx:~/julia> ls
bookings hello-world.jl
books.txt libs
count_files.jl list_only_files.jl
You see, that we have two directories ("libs" and "bookings") and the rest are files. Our goal is to list only files and exclude directories (folders). Let's create a file with the name list_only_files.jl in order to use it in every directory we want, and put following code into it: