File Flashcards
Ruby File
converts relative pathname to an absolute pathname; relative paths are referenced from the current working directory of the process unless dir_string is given
File::expand_path(file_name, [, dir_string])
ex
File.expand_path(‘some_file.txt’) #=> ‘/Users/anthonygiuliano/Projects/file-cms/file.txt’
ex
File.expand_path(‘some_file.txt’, ‘~’) #=> ‘/Users/anthonygiuliano/some_file.txt’
Ruby File
references the name of the current file in a Ruby program
__FILE__
Ruby File
opens the file, optionally seeks to the given offset, then returns length bytes (defaulting to the rest of the file)
File::read(name, [length [, offset]] [, opt] )
ex
file = File::read(‘some_file.txt’)
Ruby File
expands PATTERN, which is an Array of patterns or a pattern String, and returns the results as matches or as arguments given to the block
Dir::glob( pattern, [flags] ) => matches
Dir::glob( pattern, [flags] ) { |filename| block } => nil
ex
Dir.glob(‘*’) #=> Each element in this array is a string with the name and extension of a file in the current directory
Ruby File
returns the last component of the filename given in file_name
File::basename(file_name [, suffix] ) => base_name
ex
File.basename(“/home/gumby/work/ruby.rb”) #=> “ruby.rb” File.basename(“/home/gumby/work/ruby.rb”, “.rb”) #=> “ruby”
File.basename(“/home/gumby/work/ruby.rb”, “.*”) #=> “ruby”
Ruby File
deletes the named files, returning the number of names passed as arguments
File::delete(file_name, …) => integer
Ruby File
returns true if the named file is a directory, or a symlink that points at a directory, and false otherwise
File::directory?(file_name) => true or false
Ruby File
returns all components of the filename given in file_name except the last one
File::dirname(file_name) => dir_name
Ruby File
return true if the named file exists
File::exist?(file_name) => true or false
Ruby File
returns the extension (the portion of file name in path starting from the last period).
File::extname(path) => string
ex
File.extname(“test.rb”) #=> “.rb” File.extname(“a/b/d/test.rb”) #=> “.rb”
File.extname(“foo.”) #=> “”
File.extname(“test”) #=> “”
File.extname(“.profile”) #=> “”
File.extname(“.profile.sh”) #=> “.sh”
Ruby File
returns a new string formed by joining the strings using File::SEPARATOR
File::join(string, …) => string
Ruby File
opens the file named by filename according to the given mode and returns a new File object
File::new(filename, mode=”r” [, opt]) => file
ex
f = File.new(“testfile”, “r”)
f = File.new(“newfile”, “w+”)
Ruby File
with no associated block, this is a synonym for ::new; if the optional code block is given, it will be passed the opened file as an argument and the File object will automatically be closed when the block terminates; the value of the block will be returned
File::open(filename, mode=”r” [, opt]) {|file| block } => obj
Ruby File
renames the given file to the new name
File::rename(old_name, new_name) => 0
Ruby File
splits the given string into a directory and a file component and returns them in a two-element array
File::split(file_name) => array
ex
File.split(“/home/gumby/.profile”) #=> [“/home/gumby”, “.profile”]
Ruby File
returns true if ios is at end of file that means there are no more data to read
IO#eof? => true or false
ex
f = File.new(“testfile”)
dummy = f.readlines
f.eof? #=> true
Ruby File
closes ios and flushes any pending writes to the operating system
IO#close => true or false
Ruby File
opens the file, optionally seeks to the given offset, writes string, then returns the length written
IO::write(name, string, [offset], open_args ) => fixnum
Ruby File
different ‘modes’ for opening files in Ruby
‘r’ # read (existing file)
‘r+’ # read / write (existing file)
‘w’ # write only (creates new file)
‘w+’ # read / write (creates new file)
‘a’ # write only (appends or creates)
‘a+’ # read / write (appends or creates)
Ruby File
File::expand_path(file_name, [, dir_string])
ex
File.expand_path(‘some_file.txt’) #=> ‘/Users/anthonygiuliano/Projects/file-cms/file.txt’
ex
File.expand_path(‘some_file.txt’, ‘~’) #=> ‘/Users/anthonygiuliano/some_file.txt’
converts relative pathname to an absolute pathname; relative paths are referenced from the current working directory of the process unless dir_string is given
Ruby File
__FILE__
references the name of the current file in a Ruby program
Ruby File
File::read(name, [length [, offset]] [, opt] )
ex
file = File::read(‘some_file.txt’)
opens the file, optionally seeks to the given offset, then returns length bytes (defaulting to the rest of the file)
Ruby File
Dir::glob( pattern, [flags] ) => matches
Dir::glob( pattern, [flags] ) { |filename| block } => nil
ex
Dir.glob(‘*’) #=> Each element in this array is a string with the name and extension of a file in the current directory
expands PATTERN, which is an Array of patterns or a pattern String, and returns the results as matches or as arguments given to the block
Ruby File
File::basename(file_name [, suffix] ) => base_name
ex
File.basename(“/home/gumby/work/ruby.rb”) #=> “ruby.rb” File.basename(“/home/gumby/work/ruby.rb”, “.rb”) #=> “ruby”
File.basename(“/home/gumby/work/ruby.rb”, “.*”) #=> “ruby”
returns the last component of the filename given in file_name
Ruby File
File::delete(file_name, …) => integer
deletes the named files, returning the number of names passed as arguments
Ruby File
File::directory?(file_name) => true or false
returns true if the named file is a directory, or a symlink that points at a directory, and false otherwise
Ruby File
File::dirname(file_name) => dir_name
returns all components of the filename given in file_name except the last one
Ruby File
File::exist?(file_name) => true or false
return true if the named file exists
Ruby File
File::extname(path) => string
ex
File.extname(“test.rb”) #=> “.rb” File.extname(“a/b/d/test.rb”) #=> “.rb”
File.extname(“foo.”) #=> “”
File.extname(“test”) #=> “”
File.extname(“.profile”) #=> “”
File.extname(“.profile.sh”) #=> “.sh”
returns the extension (the portion of file name in path starting from the last period).
Ruby File
File::join(string, …) => string
returns a new string formed by joining the strings using File::SEPARATOR
Ruby File
File::new(filename, mode=”r” [, opt]) => file
ex
f = File.new(“testfile”, “r”)
f = File.new(“newfile”, “w+”)
opens the file named by filename according to the given mode and returns a new File object
Ruby File
File::open(filename, mode=”r” [, opt]) {|file| block } => obj
with no associated block, this is a synonym for ::new; if the optional code block is given, it will be passed the opened file as an argument and the File object will automatically be closed when the block terminates; the value of the block will be returned
Ruby File
File::rename(old_name, new_name) => 0
renames the given file to the new name
Ruby File
File::split(file_name) => array
ex
File.split(“/home/gumby/.profile”) #=> [“/home/gumby”, “.profile”]
splits the given string into a directory and a file component and returns them in a two-element array
Ruby File
IO#eof? => true or false
ex
f = File.new(“testfile”)
dummy = f.readlines
f.eof? #=> true
returns true if ios is at end of file that means there are no more data to read
Ruby File
IO#close => true or false
closes ios and flushes any pending writes to the operating system
Ruby File
IO::write(name, string, [offset], open_args ) => fixnum
opens the file, optionally seeks to the given offset, writes string, then returns the length written
Ruby File
‘r’ # read (existing file)
‘r+’ # read / write (existing file)
‘w’ # write only (creates new file)
‘w+’ # read / write (creates new file)
‘a’ # write only (appends or creates)
‘a+’ # read / write (appends or creates)
different ‘modes’ for opening files in Ruby
