Class: File

Inherits:
Object show all
Defined in:
lib/pleasant_path/file.rb

Class Method Summary collapse

Class Method Details

.common_path(paths) ⇒ String

Returns the longest path that all given paths have in common.

Examples:

File.common_path(["a/b/x", "a/b/y", "a/b/z"])  # == "a/b/"
File.common_path(["a/bx", "a/by", "a/bz"])     # == "a/"
File.common_path(["a/b/x", "a/b", "a"])        # == "a"

Parameters:

Returns:



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# File 'lib/pleasant_path/file.rb', line 14

def self.common_path(paths)
  return paths.first if paths.length <= 1
  short, long = paths.minmax
  i = 0
  last = -1
  while i < short.length && short[i] == long[i]
    last = i if short[i] == "/"
    i += 1
  end
  short[0, i == short.length ? i : (last + 1)]
end

.edit_lines(filename, eol: $/) {|lines| ... } ⇒ Array<String>

Reads the file indicated by filename, and yields the entire contents as an Array of lines to the given block for editing. Writes the return value of the block back to the file, overwriting previous contents. eol (end-of-line) characters are stripped from each line when reading, and appended to each line when writing. Returns the return value of the block.

Examples:

Dedup lines of file

File.read("entries.txt")  # == "AAA\nBBB\nBBB\nCCC\nAAA\n"

File.edit_lines("entries.txt", &:uniq)
  # == ["AAA", "BBB", "CCC"]

File.read("entries.txt")  # == "AAA\nBBB\nCCC\n"

Parameters:

Yields:

  • (lines)

Yield Parameters:

Yield Returns:

Returns:



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# File 'lib/pleasant_path/file.rb', line 78

def self.edit_lines(filename, eol: $/)
  self.open(filename, "r+") do |f|
    lines = yield f.read_lines(eol: eol)
    f.seek(0, IO::SEEK_SET)
    f.write_lines(lines, eol: eol)
    f.truncate(f.pos)
    lines
  end
end

.edit_text(filename) {|text| ... } ⇒ String

Reads the file indicated by filename, and yields the entire contents as a String to the given block for editing. Writes the return value of the block back to the file, overwriting previous contents. Returns the return value of the block.

Examples:

Update JSON data file

File.read("data.json")  # == '{"nested":{"key":"value"}}'

File.edit_text("data.json") do |text|
  data = JSON.parse(text)
  data["nested"]["key"] = "new value"
  data.to_json
end                     # == '{"nested":{"key":"new value"}}'

File.read("data.json")  # == '{"nested":{"key":"new value"}}'

Parameters:

Yields:

  • (text)

Yield Parameters:

Yield Returns:

Returns:



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# File 'lib/pleasant_path/file.rb', line 47

def self.edit_text(filename)
  self.open(filename, "r+") do |f|
    text = yield f.read
    f.seek(0, IO::SEEK_SET)
    f.write(text)
    f.truncate(f.pos)
    text
  end
end