Class: Csvdb::Table

Inherits:
Object
  • Object
show all
Defined in:
lib/csvdb/table.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(opts = {}) ⇒ Table

Returns a new instance of Table.



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# File 'lib/csvdb/table.rb', line 14

def initialize(opts = {})
  if opts[:name]
    @table_name = opts[:name]
  else
    raise TableError, 'No name on that table'
  end

  if opts[:file]
    @file = opts[:file]
    table = CSV.read(@file)
    @cols = table[0].map.with_index {|head,idx| [head.to_sym,idx] }.to_h
    table.delete_at(0)
  elsif opts[:ary]
    table = opts[:ary]
    @cols = opts[:cols]
  else
    raise TableError, 'No table or file to parse.'
  end

  @cols.each do |col, val|
    add_attr(col, val)
  end

  @table = []
  table.each_with_index do |row, idx|
    @table[idx] = Row.new(row, self, idx)
  end

end

Instance Attribute Details

#cols ⇒ Object

Returns the value of attribute cols.



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# File 'lib/csvdb/table.rb', line 12

def cols
  @cols
end

#table ⇒ Object

Returns the value of attribute table.



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# File 'lib/csvdb/table.rb', line 12

def table
  @table
end

#table_name ⇒ Object

Returns the value of attribute table_name.



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# File 'lib/csvdb/table.rb', line 12

def table_name
  @table_name
end

Instance Method Details

#add(attrs) ⇒ Object 



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# File 'lib/csvdb/table.rb', line 70

def add(attrs)
  @table << Row.new(attrs, self, @table.length)
end

#all ⇒ Object 



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# File 'lib/csvdb/table.rb', line 54

def all
  @table
end

#count ⇒ Object 



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# File 'lib/csvdb/table.rb', line 58

def count
  @table.count
end

#create(attrs) ⇒ Object 



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# File 'lib/csvdb/table.rb', line 62

def create(attrs)
  new_row = []
  attrs.each do |att, new_val|
    new_row[@cols[att]] = new_val
  end
  @table << Row.new(new_row, self, @table.length)
end

#find(idx = nil) ⇒ Object 



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# File 'lib/csvdb/table.rb', line 104

def find(idx = nil)
  if block_given?
    @table.select { |row| yield(row) }.first
  elsif idx
    @table[idx]
  else
    raise ArgumentError, 'Must pass either an index or a block.'
  end
end

#join(table, opts = {}) ⇒ Object 



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# File 'lib/csvdb/table.rb', line 82

def join(table, opts = {})
  col1 = opts[:col1] ; idx1 = self.send(col1)
  col2 = opts[:col2] ; idx2 = self.send(col2)
  cols = ([col1] + (self.cols.keys - [col1])
            .map { |k| "#{k}_#{self.table_name}".to_sym } +
            ((table.cols.keys - [col1])
            .map { |k| "#{k}_#{table.table_name}".to_sym }))
            .map.with_index {|head,idx| [head.to_sym,idx] }.to_h

  joined = Table.new(ary: [], cols: cols, name: "#{self.table_name}.#{cols[:col1]} join #{table.table_name}.#{cols[:col2]}")
  ids = (self.pluck(col1) + table.pluck(col2)).uniq
  ids.each do |id|
    self.where { |row| row[idx1] == id }.table.each do |outer_row|
      table.where { |row| row[idx2] == id }.table.each do |inner_row|
        inner_row.delete_at(idx2)
        joined.add(outer_row + inner_row)
      end
    end
  end
  return joined
end

#pluck(header) ⇒ Object

Raises:



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# File 'lib/csvdb/table.rb', line 114

def pluck(header)
  col = @cols[header.to_sym] ; vals = []
  raise SearchError, "Column #{header} does not exist." unless col
  @table.each do |row|
    vals << row[col]
  end
  vals
end

#pretty ⇒ Object 



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# File 'lib/csvdb/table.rb', line 123

def pretty
  table = Terminal::Table.new headings: @cols.keys, rows: @table
  puts table
end

#where(search_name = 'search') ⇒ Object 



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# File 'lib/csvdb/table.rb', line 74

def where(search_name = 'search')
  Table.new(
    ary: @table.select { |row| yield(row) },
    cols: self.cols,
    name: search_name
  )
end

#write(file = @file) ⇒ Object 



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# File 'lib/csvdb/table.rb', line 44

def write(file = @file)
  File.open(file, 'w') unless File.file?(file)
  CSV.open(file, 'wb') do |csv|
    csv << @cols.keys
    @table.each do |row|
      csv << row
    end
  end
end