Module: RIO::IF::CSV

Included in:
Rio
Defined in:
lib/rio/if/csv.rb

Instance Method Summary collapse

Instance Method Details

#columns(*ranges, &block) ⇒ Object

Select columns from a CSV file. See #csv and RIO::Doc::INTRO.



71
 
# File 'lib/rio/if/csv.rb', line 71

def columns(*ranges,&block) target.columns(*ranges,&block); self end

#csv(field_separator = ',', record_separator = nil, &block) ⇒ Object

Puts a Rio in CSV mode and sets the field and record separators. In csv mode selecting with IF::GrandeStream#records will cause each line read to be parsed into a line with the CSV standard library. Specifying using IF::GrandeStream#lines to select will return unparsed strings as normal.

# copy a csv file, changing the field separator
rio('afile.csv').csv > rio('afile_semicolons.csv').csv(';')

CSV mode also adds two methods #columns and #skipcolumns which allows selecting columns by column index using Fixnums or Ranges in a way similar to how lines are selected.

# iterate through every line but only get the first three columns
rio("afile.csv").csv.columns(0..2) { |array_of_fields| ... }

# iterate through every line but skip the columns 2 and 3 through 5
rio("afile.csv").csv.skipcolumns(2,3..5) { |array_of_fields| ... }

# an array containg all but the first line returning columns 5,6 and 7
rio("afile.csv").csv.columns(5..7).skiplines[0]

See RIO::Doc::INTRO for complete documentation on csv mode.



66
67
68
69
 
# File 'lib/rio/if/csv.rb', line 66

def csv(field_separator=',',record_separator=nil,&block) 
  target.csv(field_separator,record_separator,&block); 
  self 
end

#skipcolumns(*ranges, &block) ⇒ Object

Reject columns from a CSV file. See #csv and RIO::Doc::INTRO.



73
 
# File 'lib/rio/if/csv.rb', line 73

def skipcolumns(*ranges,&block) target.skipcolumns(*ranges,&block); self end