9 PLEAC Julia: Directories¶

PLEAC = Language Examples Alike Cookbook PLEAC examples are drawn from the "Perl Cookbook" by Tom Christiansen & Nathan Torkington, published by O'Reilly. They provide a nice range of examples oriented toward data munging, the type of work I tend to want to do first when learning a new language.

The Julia examples below are principally translations from the Python version

Caution¶

I'm learning as I go, so the code below probably doesn't represent best practice. Your suggestions are welcome! Please file an issue or make a pull request to the github repo.

The examples are not complete. Missing items are generally noted in comments.

9.1 Introduction¶

In [110]:

#save start path
HOME=pwd()
#make a file
contents="""Here are\na few\nlines of\ntext content."""
open("julia_file.txt", "w") do fo
  write(fo, contents)
end

Out[110]:

In [2]:

mystat = stat("julia_file.txt")

Stat(mode=100666, size=37)

Out[2]:

In [3]:

dump(mystat)

Stat 
  device: Uint64 0
  inode: Uint64 0
  mode: Uint64 33206
  nlink: Int64 1
  uid: Uint64 0
  gid: Uint64 0
  rdev: Uint64 0
  size: Int64 37
  blksize: Int64 0
  blocks: Int64 0
  mtime: Float64 1.389181948430809e9
  ctime: Float64 101449.959148361

In [4]:

_ctime = ctime("julia_file.txt")

Out[4]:

101449.959148361

In [5]:

_filesize = filesize("julia_file.txt")

Out[5]:

In [9]:

#check for text in file
#NOT IMPLEMENTED
#isfile("julia_file.txt") & _filesize>0 & ???

In [16]:

#list files in dir in repl
#from IJulia just use ;ls
mylist = readdir()'

Out[16]:

1x29 Array{String,2}:
 ".git"  ".gitattributes"  ".gitignore"  …  "test0.csv"  "test1.csv"

9.2 Getting and Setting Timestamps¶

In [24]:

#readtime  : file atime is not supported
writetime = mystat.mtime

Out[24]:

1.389181948430809e9

In [28]:

touch("julia_test.txt")

9.3 Deleting a File¶

In [15]:

#make a file
contents="""Here are\na few\nlines of\ntext content."""
open("julia_tmp.txt", "w") do fo
  write(fo, contents)
end

Out[15]:

In [16]:

filename = "julia_tmp.txt" 
#if isfile(filename)
try 
    rm(filename)
catch 
    println("couldn't remove file $filename")
end

9.4 Copying or Moving a File¶

In [30]:

cp("julia_test.txt","julia_test2.txt")

In [32]:

mv("julia_test2.txt","julia_test3.txt")

9.5 Recognizing Two Names for the Same File¶

In [38]:

# doesn't seem to work with Windows.
myfiles = readdir() #just looking within a single directory...
seen=Dict()
for f in myfiles
    mystat = stat(f)
    key = (mystat.device, mystat.inode)
    if haskey(seen, key)
       seen[key] +=1
    else
        seen[key] = 0
    end
end
seen
#dump(mystat)
#Stat    device: Uint64 0    inode: Uint64 0

Out[38]:

{(0x0000000000000000,0x0000000000000000)=>30}

9.6 Processing All Files in a Directory¶

In [48]:

fl = {Any}[]
for f in readdir()
   #do something
   print(f)
end

.git.gitattributes.gitignore.ipynb_checkpoints1_pleac_string.html1_pleac_string.ipynb2_pleac_numbers.html2_pleac_numbers.ipynb3_pleac_datetime-calendar.html3_pleac_datetime-calendar.ipynb3_pleac_datetime.html3_pleac_datetime.ipynb4_pleac_arrays.html4_pleac_arrays.ipynb5_pleac_dictionaries.html5_pleac_dictionaries.ipynb8_pleac_file_contents.ipynb9_pleac_directories.ipynbbintest.datjulia_file.txtjulia_file.txt2julia_file2.txtjulia_fixed.datjulia_test.txtjulia_test3.txtLICENSE.txtpleac_string.htmlREADME.mdtest.initest0.csvtest1.csv

9.7 Globbing, or Getting a List of Filenames Matching a Pattern¶

TODO: write a nicer glob() function using readdir() + glob=>regex conversion

In [54]:

@windows_only function wincmd(cmdstr)
  """run a command in windows"""
  _cmd = `CMD /C $cmdstr`
  return readall(_cmd)
end

Out[54]:

wincmd (generic function with 1 method)

In [53]:

#@readdir("*.csv")
run(`CMD /C dir *.csv`) 

 Volume in drive C is WIN7_64
 Volume Serial Number is 0A20-76D1

 Directory of c:\keithc\julia\ijulia_pleac\IJulia_PLEAC

10/31/2013  05:54 AM                51 test0.csv
10/31/2013  05:52 AM                65 test1.csv
               2 File(s)            116 bytes
               0 Dir(s)  56,786,563,072 bytes free

In [62]:

[split(f)[end] for f in split(wincmd("dir *.csv"),"\r\n")[6:end-3]]

Out[62]:

2-element Array{String,1}:
 "test0.csv"
 "test1.csv"

9.8 Processing All Files in a Directory Recursively¶

In [63]:

function walk_files(path)
    for fn in readdir(path)
        if isdir(fn) 
           walk_files(fn)   
        else
            println(fn)
        end        
    end 
    return
end

Out[63]:

walk_files (generic function with 1 method)

In [65]:

walk_files("C:\\keithc\\julia\\ijulia_default")

1_pleac_string-checkpoint.ipynb
2_pleac_numbers-checkpoint.ipynb
3_pleac_datetime-calendar-checkpoint.ipynb
3_pleac_datetime-checkpoint.ipynb
4_pleac_arrays-checkpoint.ipynb
5_pleac_dictionaries-checkpoint.ipynb
8_pleac_file_contents-checkpoint.ipynb
9_pleac_directories-checkpoint.ipynb
Cirrus - Copy.ipynb
Cirrus.html
Cirrus.ipynb
CSV and Text IO.ipynb
Dataframes test.ipynb
file and system.ipynb
Julia 12.ipynb
Julia 24.ipynb
julia_dataframe_gadfly.ipynb
libexpat_test.ipynb
SingaporeWeather.html
SingaporeWeather.ipynb
test2.h5
test2.jld
test3.jld
test_HDF5.jl.ipynb
Untitled0.ipynb
Untitled1.ipynb

9.9 Removing a Directory and Its Contents¶

In [139]:

function rmdir_all(absolute_path)
   stdir = pwd()
   cd(absolute_path)
   #println("rmdir_all: $absolute_path")
   for fn in readdir()
        #println(fn)
        if isdir(fn)
           #println("dir: $fn")
           rmdir_all(fn)   
        else
           #println("rm: $fn")
           rm(fn)
        end        
   end 
   #println("finish up")
   cd("..")
   #println("pwd: $(pwd())  rmdir: $absolute_path")
   rmdir(absolute_path) 
   cd(stdir)
end

Out[139]:

rmdir_all (generic function with 1 method)

In [141]:

rmdir_all("C:\\keithc\\Temp")

9.10 Renaming Files¶

In [111]:

cd(HOME)

In [113]:

fn="julia_test.txt"
fn2=replace(fn, ".txt","2.txt")
cp(fn,fn2)

In [114]:

mv(fn2, replace(fn2, "2.txt","77.txt"))

9.11 Splitting a Filename into its Component Parts¶

In [124]:

testfile="$HOME$(readdir(HOME)[1])"

Out[124]:

"C:\\keithc\\julia\\ijulia_pleac\\IJulia_PLEAC.git"

In [126]:

_basename = basename(testfile)

Out[126]:

"IJulia_PLEAC.git"

In [117]:

dirname(HOME)

Out[117]:

"C:\\keithc\\julia\\ijulia_pleac"

In [134]:

maximum(search(_basename,".")) > 0

Out[134]:

true

In [137]:

function file_extension(path)
   _basename = basename(path)
    return maximum(search(_basename,"."))>0 ? split(_basename,'.')[end] : ""
end

Out[137]:

file_extension (generic function with 1 method)

In [138]:

file_extension(_basename)

Out[138]:

"git"

Programs¶

In [ ]:

#not implemented