Get the content of a file

ruby-talk
1

Hi.

I've a method to read the content of a file.

def readFile(path)
   value = ''
   file = File.open(path, File::RDONLY)
   while line = file.gets do
     value += line
   end
   file.close
   return value
end

I think the way line by line is not very efficiently.
Is there a shorter way to get the content of a file?

greetings
Dirk Einecke

2

Is there a shorter way to get the content of a file?

svg% ri IO::read
--------------------------------------------------------------- IO::read
     IO.read(rane, [length [, offset]] ) => string

···

------------------------------------------------------------------------
     Opens the file, optionally seeks to the given offset, then returns
     _length_ bytes (defaulting to the rest of the file). +read+ ensures
     the file is closed before returning.

        IO.read("testfile") #=> "This is line one\nThis is line two\
nThis is line three\nAnd so on...\n"
        IO.read("testfile", 20) #=> "This is line one\nThi"
        IO.read("testfile", 20, 10) #=> "ne one\nThis is line "

svg%

Guy Decoux

3

Dirk Einecke wrote:

Is there a shorter way to get the content of a file?

File.read(filename)

4

Dirk Einecke wrote:

Hi.

I've a method to read the content of a file.

def readFile(path)
  value = ''
  file = File.open(path, File::RDONLY)
  while line = file.gets do
    value += line
  end
  file.close
  return value
end

I think the way line by line is not very efficiently.
Is there a shorter way to get the content of a file?

greetings
Dirk Einecke

Simple way is:

content = File.read(filename)

But if you should learn about blocks so the code you provided can be replaced with something like the following (because your code doesn't have exception handling to guarantee that file.close is called):

File.open(path, File::RDONLY){|file|
     #use file.gets or whatever in here, preferably using another block
}

5

I use the following idiom to read the whole file:

data = open(path) {|f| f.read}

Cheers,
Kent.

···

On Jul 25, 2004, at 4:56 AM, Dirk Einecke wrote:

Hi.

I've a method to read the content of a file.

def readFile(path)
  value = ''
  file = File.open(path, File::RDONLY)
  while line = file.gets do
    value += line
  end
  file.close
  return value
end

I think the way line by line is not very efficiently.
Is there a shorter way to get the content of a file?

greetings
Dirk Einecke

6

Hi.

Well - thanks to all. Now I've several ways:

1.
value = open(path) {|f| f.read}

2.
file = File.open(path, File::RDONLY)
value = file.read
file.close

3.
value = File.readlines(path).to_s

4.
value = File.readlines(path).join

What is the fastes way (for Ruby) and what should I use?

greetings
Dirk Einecke

7

Hi.

Andreas Schwarz wrote:

Dirk Einecke wrote:

Is there a shorter way to get the content of a file?

File.read(filename)

That's not working and I can not find read() here: http://www.rubycentral.com/ref/ref_c_file.html

I'm using Ruby 1.6.7

greetings
Dirk Einecke

8

Dirk Einecke <dirk.einecke@gmx.de> writes:

Hi.

Well - thanks to all. Now I've several ways:

1.
value = open(path) {|f| f.read}

2.
file = File.open(path, File::RDONLY)
value = file.read
file.close

3.
value = File.readlines(path).to_s

4.
value = File.readlines(path).join

What is the fastes way (for Ruby) and what should I use?

greetings
Dirk Einecke

In my opinion, number one is the best. The latter two only make sense
for line-based formats, and even in such cases it's easier to just read
it all in at once. Number two, I assume, is just like number one,
except you have to close it up yourself, which is annoying.

  mikael

9

Dirk Einecke wrote:

Hi.

Well - thanks to all. Now I've several ways:

1.
value = open(path) {|f| f.read}

2.
file = File.open(path, File::RDONLY)
value = file.read
file.close

2b.

value = File.open(path) {|f| f.read}

3.
value = File.readlines(path).to_s

4.
value = File.readlines(path).join

What is the fastes way (for Ruby) and what should I use?

1. and 2. should be the fastest!

Regards,

  Michael

10

Dirk Einecke wrote:

Hi.

Andreas Schwarz wrote:

Dirk Einecke wrote:

Is there a shorter way to get the content of a file?

File.read(filename)

That's not working and I can not find read() here: http://www.rubycentral.com/ref/ref_c_file.html

I'm using Ruby 1.6.7

greetings
Dirk Einecke

Look here http://www.rubycentral.com/ref/ref_c_io.html#read . You are dealing with an IO object (the file) so you can use the IO methods.

You can do something like
aFile = File.new("#{textfilename}", "r")
contentsoffile = aFile.read

-Matthew Margolis

11

Dirk Einecke wrote:

Hi.

Andreas Schwarz wrote:

Dirk Einecke wrote:

Is there a shorter way to get the content of a file?

File.read(filename)

That's not working and I can not find read() here: http://www.rubycentral.com/ref/ref_c_file.html

I'm using Ruby 1.6.7

What I did in Ruby < 1.8 is the following:

   File.readlines(filename).to_s

or instead of to_s, join("")

Regards,

   Michael

12

Hi.

Michael Neumann wrote:

value = File.open(path) {|f| f.read}

Okay - I take this one.

greetings
Dirk Einecke

13

What about,
value = File.read(path)

···

On Mon, 2 Aug 2004 02:46:38 +0900, Dirk Einecke <dirk.einecke@gmx.de> wrote:

Hi.

Michael Neumann wrote:
> value = File.open(path) {|f| f.read}

Okay - I take this one.

greetings
Dirk Einecke