lib/csv/table.rb
# frozen_string_literal: true
require "forwardable"
class CSV
# = \CSV::Table
# A \CSV::Table instance represents \CSV data.
# (see {class CSV}[../CSV.html]).
#
# The instance may have:
# - Rows: each is a Table::Row object.
# - Headers: names for the columns.
#
# === Instance Methods
#
# \CSV::Table has three groups of instance methods:
# - Its own internally defined instance methods.
# - Methods included by module Enumerable.
# - Methods delegated to class Array.:
# * Array#empty?
# * Array#length
# * Array#size
#
# == Creating a \CSV::Table Instance
#
# Commonly, a new \CSV::Table instance is created by parsing \CSV source
# using headers:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.class # => CSV::Table
#
# You can also create an instance directly. See ::new.
#
# == Headers
#
# If a table has headers, the headers serve as labels for the columns of data.
# Each header serves as the label for its column.
#
# The headers for a \CSV::Table object are stored as an \Array of Strings.
#
# Commonly, headers are defined in the first row of \CSV source:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.headers # => ["Name", "Value"]
#
# If no headers are defined, the \Array is empty:
# table = CSV::Table.new([])
# table.headers # => []
#
# == Access Modes
#
# \CSV::Table provides three modes for accessing table data:
# - \Row mode.
# - Column mode.
# - Mixed mode (the default for a new table).
#
# The access mode for a\CSV::Table instance affects the behavior
# of some of its instance methods:
# - #[]
# - #[]=
# - #delete
# - #delete_if
# - #each
# - #values_at
#
# === \Row Mode
#
# Set a table to row mode with method #by_row!:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.by_row! # => #<CSV::Table mode:row row_count:4>
#
# Specify a single row by an \Integer index:
# # Get a row.
# table[1] # => #<CSV::Row "Name":"bar" "Value":"1">
# # Set a row, then get it.
# table[1] = CSV::Row.new(['Name', 'Value'], ['bam', 3])
# table[1] # => #<CSV::Row "Name":"bam" "Value":3>
#
# Specify a sequence of rows by a \Range:
# # Get rows.
# table[1..2] # => [#<CSV::Row "Name":"bam" "Value":3>, #<CSV::Row "Name":"baz" "Value":"2">]
# # Set rows, then get them.
# table[1..2] = [
# CSV::Row.new(['Name', 'Value'], ['bat', 4]),
# CSV::Row.new(['Name', 'Value'], ['bad', 5]),
# ]
# table[1..2] # => [["Name", #<CSV::Row "Name":"bat" "Value":4>], ["Value", #<CSV::Row "Name":"bad" "Value":5>]]
#
# === Column Mode
#
# Set a table to column mode with method #by_col!:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.by_col! # => #<CSV::Table mode:col row_count:4>
#
# Specify a column by an \Integer index:
# # Get a column.
# table[0]
# # Set a column, then get it.
# table[0] = ['FOO', 'BAR', 'BAZ']
# table[0] # => ["FOO", "BAR", "BAZ"]
#
# Specify a column by its \String header:
# # Get a column.
# table['Name'] # => ["FOO", "BAR", "BAZ"]
# # Set a column, then get it.
# table['Name'] = ['Foo', 'Bar', 'Baz']
# table['Name'] # => ["Foo", "Bar", "Baz"]
#
# === Mixed Mode
#
# In mixed mode, you can refer to either rows or columns:
# - An \Integer index refers to a row.
# - A \Range index refers to multiple rows.
# - A \String index refers to a column.
#
# Set a table to mixed mode with method #by_col_or_row!:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.by_col_or_row! # => #<CSV::Table mode:col_or_row row_count:4>
#
# Specify a single row by an \Integer index:
# # Get a row.
# table[1] # => #<CSV::Row "Name":"bar" "Value":"1">
# # Set a row, then get it.
# table[1] = CSV::Row.new(['Name', 'Value'], ['bam', 3])
# table[1] # => #<CSV::Row "Name":"bam" "Value":3>
#
# Specify a sequence of rows by a \Range:
# # Get rows.
# table[1..2] # => [#<CSV::Row "Name":"bam" "Value":3>, #<CSV::Row "Name":"baz" "Value":"2">]
# # Set rows, then get them.
# table[1] = CSV::Row.new(['Name', 'Value'], ['bat', 4])
# table[2] = CSV::Row.new(['Name', 'Value'], ['bad', 5])
# table[1..2] # => [["Name", #<CSV::Row "Name":"bat" "Value":4>], ["Value", #<CSV::Row "Name":"bad" "Value":5>]]
#
# Specify a column by its \String header:
# # Get a column.
# table['Name'] # => ["foo", "bat", "bad"]
# # Set a column, then get it.
# table['Name'] = ['Foo', 'Bar', 'Baz']
# table['Name'] # => ["Foo", "Bar", "Baz"]
class Table
# :call-seq:
# CSV::Table.new(array_of_rows, headers = nil) -> csv_table
#
# Returns a new \CSV::Table object.
#
# - Argument +array_of_rows+ must be an \Array of CSV::Row objects.
# - Argument +headers+, if given, may be an \Array of Strings.
#
# ---
#
# Create an empty \CSV::Table object:
# table = CSV::Table.new([])
# table # => #<CSV::Table mode:col_or_row row_count:1>
#
# Create a non-empty \CSV::Table object:
# rows = [
# CSV::Row.new([], []),
# CSV::Row.new([], []),
# CSV::Row.new([], []),
# ]
# table = CSV::Table.new(rows)
# table # => #<CSV::Table mode:col_or_row row_count:4>
#
# ---
#
# If argument +headers+ is an \Array of Strings,
# those Strings become the table's headers:
# table = CSV::Table.new([], headers: ['Name', 'Age'])
# table.headers # => ["Name", "Age"]
#
# If argument +headers+ is not given and the table has rows,
# the headers are taken from the first row:
# rows = [
# CSV::Row.new(['Foo', 'Bar'], []),
# CSV::Row.new(['foo', 'bar'], []),
# CSV::Row.new(['FOO', 'BAR'], []),
# ]
# table = CSV::Table.new(rows)
# table.headers # => ["Foo", "Bar"]
#
# If argument +headers+ is not given and the table is empty (has no rows),
# the headers are also empty:
# table = CSV::Table.new([])
# table.headers # => []
#
# ---
#
# Raises an exception if argument +array_of_rows+ is not an \Array object:
# # Raises NoMethodError (undefined method `first' for :foo:Symbol):
# CSV::Table.new(:foo)
#
# Raises an exception if an element of +array_of_rows+ is not a \CSV::Table object:
# # Raises NoMethodError (undefined method `headers' for :foo:Symbol):
# CSV::Table.new([:foo])
def initialize(array_of_rows, headers: nil)
@table = array_of_rows
@headers = headers
unless @headers
if @table.empty?
@headers = []
else
@headers = @table.first.headers
end
end
@mode = :col_or_row
end
# The current access mode for indexing and iteration.
attr_reader :mode
# Internal data format used to compare equality.
attr_reader :table
protected :table
### Array Delegation ###
extend Forwardable
def_delegators :@table, :empty?, :length, :size
# :call-seq:
# table.by_col -> table_dup
#
# Returns a duplicate of +self+, in column mode
# (see {Column Mode}[#class-CSV::Table-label-Column+Mode]):
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.mode # => :col_or_row
# dup_table = table.by_col
# dup_table.mode # => :col
# dup_table.equal?(table) # => false # It's a dup
#
# This may be used to chain method calls without changing the mode
# (but also will affect performance and memory usage):
# dup_table.by_col['Name']
#
# Also note that changes to the duplicate table will not affect the original.
def by_col
self.class.new(@table.dup).by_col!
end
# :call-seq:
# table.by_col! -> self
#
# Sets the mode for +self+ to column mode
# (see {Column Mode}[#class-CSV::Table-label-Column+Mode]); returns +self+:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.mode # => :col_or_row
# table1 = table.by_col!
# table.mode # => :col
# table1.equal?(table) # => true # Returned self
def by_col!
@mode = :col
self
end
# :call-seq:
# table.by_col_or_row -> table_dup
#
# Returns a duplicate of +self+, in mixed mode
# (see {Mixed Mode}[#class-CSV::Table-label-Mixed+Mode]):
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true).by_col!
# table.mode # => :col
# dup_table = table.by_col_or_row
# dup_table.mode # => :col_or_row
# dup_table.equal?(table) # => false # It's a dup
#
# This may be used to chain method calls without changing the mode
# (but also will affect performance and memory usage):
# dup_table.by_col_or_row['Name']
#
# Also note that changes to the duplicate table will not affect the original.
def by_col_or_row
self.class.new(@table.dup).by_col_or_row!
end
# :call-seq:
# table.by_col_or_row! -> self
#
# Sets the mode for +self+ to mixed mode
# (see {Mixed Mode}[#class-CSV::Table-label-Mixed+Mode]); returns +self+:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true).by_col!
# table.mode # => :col
# table1 = table.by_col_or_row!
# table.mode # => :col_or_row
# table1.equal?(table) # => true # Returned self
def by_col_or_row!
@mode = :col_or_row
self
end
# :call-seq:
# table.by_row -> table_dup
#
# Returns a duplicate of +self+, in row mode
# (see {Row Mode}[#class-CSV::Table-label-Row+Mode]):
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.mode # => :col_or_row
# dup_table = table.by_row
# dup_table.mode # => :row
# dup_table.equal?(table) # => false # It's a dup
#
# This may be used to chain method calls without changing the mode
# (but also will affect performance and memory usage):
# dup_table.by_row[1]
#
# Also note that changes to the duplicate table will not affect the original.
def by_row
self.class.new(@table.dup).by_row!
end
# :call-seq:
# table.by_row! -> self
#
# Sets the mode for +self+ to row mode
# (see {Row Mode}[#class-CSV::Table-label-Row+Mode]); returns +self+:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.mode # => :col_or_row
# table1 = table.by_row!
# table.mode # => :row
# table1.equal?(table) # => true # Returned self
def by_row!
@mode = :row
self
end
# :call-seq:
# table.headers -> array_of_headers
#
# Returns a new \Array containing the \String headers for the table.
#
# If the table is not empty, returns the headers from the first row:
# rows = [
# CSV::Row.new(['Foo', 'Bar'], []),
# CSV::Row.new(['FOO', 'BAR'], []),
# CSV::Row.new(['foo', 'bar'], []),
# ]
# table = CSV::Table.new(rows)
# table.headers # => ["Foo", "Bar"]
# table.delete(0)
# table.headers # => ["FOO", "BAR"]
# table.delete(0)
# table.headers # => ["foo", "bar"]
#
# If the table is empty, returns a copy of the headers in the table itself:
# table.delete(0)
# table.headers # => ["Foo", "Bar"]
def headers
if @table.empty?
@headers.dup
else
@table.first.headers
end
end
# :call-seq:
# table[n] -> row or column_data
# table[range] -> array_of_rows or array_of_column_data
# table[header] -> array_of_column_data
#
# Returns data from the table; does not modify the table.
#
# ---
#
# Fetch a \Row by Its \Integer Index::
# - Form: <tt>table[n]</tt>, +n+ an integer.
# - Access mode: <tt>:row</tt> or <tt>:col_or_row</tt>.
# - Return value: _nth_ row of the table, if that row exists;
# otherwise +nil+.
#
# Returns the _nth_ row of the table if that row exists:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.by_row! # => #<CSV::Table mode:row row_count:4>
# table[1] # => #<CSV::Row "Name":"bar" "Value":"1">
# table.by_col_or_row! # => #<CSV::Table mode:col_or_row row_count:4>
# table[1] # => #<CSV::Row "Name":"bar" "Value":"1">
#
# Counts backward from the last row if +n+ is negative:
# table[-1] # => #<CSV::Row "Name":"baz" "Value":"2">
#
# Returns +nil+ if +n+ is too large or too small:
# table[4] # => nil
# table[-4] # => nil
#
# Raises an exception if the access mode is <tt>:row</tt>
# and +n+ is not an \Integer:
# table.by_row! # => #<CSV::Table mode:row row_count:4>
# # Raises TypeError (no implicit conversion of String into Integer):
# table['Name']
#
# ---
#
# Fetch a Column by Its \Integer Index::
# - Form: <tt>table[n]</tt>, +n+ an \Integer.
# - Access mode: <tt>:col</tt>.
# - Return value: _nth_ column of the table, if that column exists;
# otherwise an \Array of +nil+ fields of length <tt>self.size</tt>.
#
# Returns the _nth_ column of the table if that column exists:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.by_col! # => #<CSV::Table mode:col row_count:4>
# table[1] # => ["0", "1", "2"]
#
# Counts backward from the last column if +n+ is negative:
# table[-2] # => ["foo", "bar", "baz"]
#
# Returns an \Array of +nil+ fields if +n+ is too large or too small:
# table[4] # => [nil, nil, nil]
# table[-4] # => [nil, nil, nil]
#
# ---
#
# Fetch Rows by \Range::
# - Form: <tt>table[range]</tt>, +range+ a \Range object.
# - Access mode: <tt>:row</tt> or <tt>:col_or_row</tt>.
# - Return value: rows from the table, beginning at row <tt>range.start</tt>,
# if those rows exists.
#
# Returns rows from the table, beginning at row <tt>range.first</tt>,
# if those rows exist:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.by_row! # => #<CSV::Table mode:row row_count:4>
# rows = table[1..2] # => #<CSV::Row "Name":"bar" "Value":"1">
# rows # => [#<CSV::Row "Name":"bar" "Value":"1">, #<CSV::Row "Name":"baz" "Value":"2">]
# table.by_col_or_row! # => #<CSV::Table mode:col_or_row row_count:4>
# rows = table[1..2] # => #<CSV::Row "Name":"bar" "Value":"1">
# rows # => [#<CSV::Row "Name":"bar" "Value":"1">, #<CSV::Row "Name":"baz" "Value":"2">]
#
# If there are too few rows, returns all from <tt>range.start</tt> to the end:
# rows = table[1..50] # => #<CSV::Row "Name":"bar" "Value":"1">
# rows # => [#<CSV::Row "Name":"bar" "Value":"1">, #<CSV::Row "Name":"baz" "Value":"2">]
#
# Special case: if <tt>range.start == table.size</tt>, returns an empty \Array:
# table[table.size..50] # => []
#
# If <tt>range.end</tt> is negative, calculates the ending index from the end:
# rows = table[0..-1]
# rows # => [#<CSV::Row "Name":"foo" "Value":"0">, #<CSV::Row "Name":"bar" "Value":"1">, #<CSV::Row "Name":"baz" "Value":"2">]
#
# If <tt>range.start</tt> is negative, calculates the starting index from the end:
# rows = table[-1..2]
# rows # => [#<CSV::Row "Name":"baz" "Value":"2">]
#
# If <tt>range.start</tt> is larger than <tt>table.size</tt>, returns +nil+:
# table[4..4] # => nil
#
# ---
#
# Fetch Columns by \Range::
# - Form: <tt>table[range]</tt>, +range+ a \Range object.
# - Access mode: <tt>:col</tt>.
# - Return value: column data from the table, beginning at column <tt>range.start</tt>,
# if those columns exist.
#
# Returns column values from the table, if the column exists;
# the values are arranged by row:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.by_col!
# table[0..1] # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
#
# Special case: if <tt>range.start == headers.size</tt>,
# returns an \Array (size: <tt>table.size</tt>) of empty \Arrays:
# table[table.headers.size..50] # => [[], [], []]
#
# If <tt>range.end</tt> is negative, calculates the ending index from the end:
# table[0..-1] # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
#
# If <tt>range.start</tt> is negative, calculates the starting index from the end:
# table[-2..2] # => [["foo", "0"], ["bar", "1"], ["baz", "2"]]
#
# If <tt>range.start</tt> is larger than <tt>table.size</tt>,
# returns an \Array of +nil+ values:
# table[4..4] # => [nil, nil, nil]
#
# ---
#
# Fetch a Column by Its \String Header::
# - Form: <tt>table[header]</tt>, +header+ a \String header.
# - Access mode: <tt>:col</tt> or <tt>:col_or_row</tt>
# - Return value: column data from the table, if that +header+ exists.
#
# Returns column values from the table, if the column exists:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.by_col! # => #<CSV::Table mode:col row_count:4>
# table['Name'] # => ["foo", "bar", "baz"]
# table.by_col_or_row! # => #<CSV::Table mode:col_or_row row_count:4>
# col = table['Name']
# col # => ["foo", "bar", "baz"]
#
# Modifying the returned column values does not modify the table:
# col[0] = 'bat'
# col # => ["bat", "bar", "baz"]
# table['Name'] # => ["foo", "bar", "baz"]
#
# Returns an \Array of +nil+ values if there is no such column:
# table['Nosuch'] # => [nil, nil, nil]
def [](index_or_header)
if @mode == :row or # by index
(@mode == :col_or_row and (index_or_header.is_a?(Integer) or index_or_header.is_a?(Range)))
@table[index_or_header]
else # by header
@table.map { |row| row[index_or_header] }
end
end
# :call-seq:
# table[n] = row -> row
# table[n] = field_or_array_of_fields -> field_or_array_of_fields
# table[header] = field_or_array_of_fields -> field_or_array_of_fields
#
# Puts data onto the table.
#
# ---
#
# Set a \Row by Its \Integer Index::
# - Form: <tt>table[n] = row</tt>, +n+ an \Integer,
# +row+ a \CSV::Row instance or an \Array of fields.
# - Access mode: <tt>:row</tt> or <tt>:col_or_row</tt>.
# - Return value: +row+.
#
# If the row exists, it is replaced:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# new_row = CSV::Row.new(['Name', 'Value'], ['bat', 3])
# table.by_row! # => #<CSV::Table mode:row row_count:4>
# return_value = table[0] = new_row
# return_value.equal?(new_row) # => true # Returned the row
# table[0].to_h # => {"Name"=>"bat", "Value"=>3}
#
# With access mode <tt>:col_or_row</tt>:
# table.by_col_or_row! # => #<CSV::Table mode:col_or_row row_count:4>
# table[0] = CSV::Row.new(['Name', 'Value'], ['bam', 4])
# table[0].to_h # => {"Name"=>"bam", "Value"=>4}
#
# With an \Array instead of a \CSV::Row, inherits headers from the table:
# array = ['bad', 5]
# return_value = table[0] = array
# return_value.equal?(array) # => true # Returned the array
# table[0].to_h # => {"Name"=>"bad", "Value"=>5}
#
# If the row does not exist, extends the table by adding rows:
# assigns rows with +nil+ as needed:
# table.size # => 3
# table[5] = ['bag', 6]
# table.size # => 6
# table[3] # => nil
# table[4]# => nil
# table[5].to_h # => {"Name"=>"bag", "Value"=>6}
#
# Note that the +nil+ rows are actually +nil+, not a row of +nil+ fields.
#
# ---
#
# Set a Column by Its \Integer Index::
# - Form: <tt>table[n] = array_of_fields</tt>, +n+ an \Integer,
# +array_of_fields+ an \Array of \String fields.
# - Access mode: <tt>:col</tt>.
# - Return value: +array_of_fields+.
#
# If the column exists, it is replaced:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# new_col = [3, 4, 5]
# table.by_col! # => #<CSV::Table mode:col row_count:4>
# return_value = table[1] = new_col
# return_value.equal?(new_col) # => true # Returned the column
# table[1] # => [3, 4, 5]
# # The rows, as revised:
# table.by_row! # => #<CSV::Table mode:row row_count:4>
# table[0].to_h # => {"Name"=>"foo", "Value"=>3}
# table[1].to_h # => {"Name"=>"bar", "Value"=>4}
# table[2].to_h # => {"Name"=>"baz", "Value"=>5}
# table.by_col! # => #<CSV::Table mode:col row_count:4>
#
# If there are too few values, fills with +nil+ values:
# table[1] = [0]
# table[1] # => [0, nil, nil]
#
# If there are too many values, ignores the extra values:
# table[1] = [0, 1, 2, 3, 4]
# table[1] # => [0, 1, 2]
#
# If a single value is given, replaces all fields in the column with that value:
# table[1] = 'bat'
# table[1] # => ["bat", "bat", "bat"]
#
# ---
#
# Set a Column by Its \String Header::
# - Form: <tt>table[header] = field_or_array_of_fields</tt>,
# +header+ a \String header, +field_or_array_of_fields+ a field value
# or an \Array of \String fields.
# - Access mode: <tt>:col</tt> or <tt>:col_or_row</tt>.
# - Return value: +field_or_array_of_fields+.
#
# If the column exists, it is replaced:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# new_col = [3, 4, 5]
# table.by_col! # => #<CSV::Table mode:col row_count:4>
# return_value = table['Value'] = new_col
# return_value.equal?(new_col) # => true # Returned the column
# table['Value'] # => [3, 4, 5]
# # The rows, as revised:
# table.by_row! # => #<CSV::Table mode:row row_count:4>
# table[0].to_h # => {"Name"=>"foo", "Value"=>3}
# table[1].to_h # => {"Name"=>"bar", "Value"=>4}
# table[2].to_h # => {"Name"=>"baz", "Value"=>5}
# table.by_col! # => #<CSV::Table mode:col row_count:4>
#
# If there are too few values, fills with +nil+ values:
# table['Value'] = [0]
# table['Value'] # => [0, nil, nil]
#
# If there are too many values, ignores the extra values:
# table['Value'] = [0, 1, 2, 3, 4]
# table['Value'] # => [0, 1, 2]
#
# If the column does not exist, extends the table by adding columns:
# table['Note'] = ['x', 'y', 'z']
# table['Note'] # => ["x", "y", "z"]
# # The rows, as revised:
# table.by_row!
# table[0].to_h # => {"Name"=>"foo", "Value"=>0, "Note"=>"x"}
# table[1].to_h # => {"Name"=>"bar", "Value"=>1, "Note"=>"y"}
# table[2].to_h # => {"Name"=>"baz", "Value"=>2, "Note"=>"z"}
# table.by_col!
#
# If a single value is given, replaces all fields in the column with that value:
# table['Value'] = 'bat'
# table['Value'] # => ["bat", "bat", "bat"]
def []=(index_or_header, value)
if @mode == :row or # by index
(@mode == :col_or_row and index_or_header.is_a? Integer)
if value.is_a? Array
@table[index_or_header] = Row.new(headers, value)
else
@table[index_or_header] = value
end
else # set column
unless index_or_header.is_a? Integer
index = @headers.index(index_or_header) || @headers.size
@headers[index] = index_or_header
end
if value.is_a? Array # multiple values
@table.each_with_index do |row, i|
if row.header_row?
row[index_or_header] = index_or_header
else
row[index_or_header] = value[i]
end
end
else # repeated value
@table.each do |row|
if row.header_row?
row[index_or_header] = index_or_header
else
row[index_or_header] = value
end
end
end
end
end
# :call-seq:
# table.values_at(*indexes) -> array_of_rows
# table.values_at(*headers) -> array_of_columns_data
#
# If the access mode is <tt>:row</tt> or <tt>:col_or_row</tt>,
# and each argument is either an \Integer or a \Range,
# returns rows.
# Otherwise, returns columns data.
#
# In either case, the returned values are in the order
# specified by the arguments. Arguments may be repeated.
#
# ---
#
# Returns rows as an \Array of \CSV::Row objects.
#
# No argument:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.values_at # => []
#
# One index:
# values = table.values_at(0)
# values # => [#<CSV::Row "Name":"foo" "Value":"0">]
#
# Two indexes:
# values = table.values_at(2, 0)
# values # => [#<CSV::Row "Name":"baz" "Value":"2">, #<CSV::Row "Name":"foo" "Value":"0">]
#
# One \Range:
# values = table.values_at(1..2)
# values # => [#<CSV::Row "Name":"bar" "Value":"1">, #<CSV::Row "Name":"baz" "Value":"2">]
#
# \Ranges and indexes:
# values = table.values_at(0..1, 1..2, 0, 2)
# pp values
# Output:
# [#<CSV::Row "Name":"foo" "Value":"0">,
# #<CSV::Row "Name":"bar" "Value":"1">,
# #<CSV::Row "Name":"bar" "Value":"1">,
# #<CSV::Row "Name":"baz" "Value":"2">,
# #<CSV::Row "Name":"foo" "Value":"0">,
# #<CSV::Row "Name":"baz" "Value":"2">]
#
# ---
#
# Returns columns data as row Arrays,
# each consisting of the specified columns data for that row:
# values = table.values_at('Name')
# values # => [["foo"], ["bar"], ["baz"]]
# values = table.values_at('Value', 'Name')
# values # => [["0", "foo"], ["1", "bar"], ["2", "baz"]]
def values_at(*indices_or_headers)
if @mode == :row or # by indices
( @mode == :col_or_row and indices_or_headers.all? do |index|
index.is_a?(Integer) or
( index.is_a?(Range) and
index.first.is_a?(Integer) and
index.last.is_a?(Integer) )
end )
@table.values_at(*indices_or_headers)
else # by headers
@table.map { |row| row.values_at(*indices_or_headers) }
end
end
# :call-seq:
# table << row_or_array -> self
#
# If +row_or_array+ is a \CSV::Row object,
# it is appended to the table:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table << CSV::Row.new(table.headers, ['bat', 3])
# table[3] # => #<CSV::Row "Name":"bat" "Value":3>
#
# If +row_or_array+ is an \Array, it is used to create a new
# \CSV::Row object which is then appended to the table:
# table << ['bam', 4]
# table[4] # => #<CSV::Row "Name":"bam" "Value":4>
def <<(row_or_array)
if row_or_array.is_a? Array # append Array
@table << Row.new(headers, row_or_array)
else # append Row
@table << row_or_array
end
self # for chaining
end
#
# :call-seq:
# table.push(*rows_or_arrays) -> self
#
# A shortcut for appending multiple rows. Equivalent to:
# rows.each {|row| self << row }
#
# Each argument may be either a \CSV::Row object or an \Array:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# rows = [
# CSV::Row.new(table.headers, ['bat', 3]),
# ['bam', 4]
# ]
# table.push(*rows)
# table[3..4] # => [#<CSV::Row "Name":"bat" "Value":3>, #<CSV::Row "Name":"bam" "Value":4>]
def push(*rows)
rows.each { |row| self << row }
self # for chaining
end
# :call-seq:
# table.delete(*indexes) -> deleted_values
# table.delete(*headers) -> deleted_values
#
# If the access mode is <tt>:row</tt> or <tt>:col_or_row</tt>,
# and each argument is either an \Integer or a \Range,
# returns deleted rows.
# Otherwise, returns deleted columns data.
#
# In either case, the returned values are in the order
# specified by the arguments. Arguments may be repeated.
#
# ---
#
# Returns rows as an \Array of \CSV::Row objects.
#
# One index:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# deleted_values = table.delete(0)
# deleted_values # => [#<CSV::Row "Name":"foo" "Value":"0">]
#
# Two indexes:
# table = CSV.parse(source, headers: true)
# deleted_values = table.delete(2, 0)
# deleted_values # => [#<CSV::Row "Name":"baz" "Value":"2">, #<CSV::Row "Name":"foo" "Value":"0">]
#
# ---
#
# Returns columns data as column Arrays.
#
# One header:
# table = CSV.parse(source, headers: true)
# deleted_values = table.delete('Name')
# deleted_values # => ["foo", "bar", "baz"]
#
# Two headers:
# table = CSV.parse(source, headers: true)
# deleted_values = table.delete('Value', 'Name')
# deleted_values # => [["0", "1", "2"], ["foo", "bar", "baz"]]
def delete(*indexes_or_headers)
if indexes_or_headers.empty?
raise ArgumentError, "wrong number of arguments (given 0, expected 1+)"
end
deleted_values = indexes_or_headers.map do |index_or_header|
if @mode == :row or # by index
(@mode == :col_or_row and index_or_header.is_a? Integer)
@table.delete_at(index_or_header)
else # by header
if index_or_header.is_a? Integer
@headers.delete_at(index_or_header)
else
@headers.delete(index_or_header)
end
@table.map { |row| row.delete(index_or_header).last }
end
end
if indexes_or_headers.size == 1
deleted_values[0]
else
deleted_values
end
end
# :call-seq:
# table.delete_if {|row_or_column| ... } -> self
#
# Removes rows or columns for which the block returns a truthy value;
# returns +self+.
#
# Removes rows when the access mode is <tt>:row</tt> or <tt>:col_or_row</tt>;
# calls the block with each \CSV::Row object:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.by_row! # => #<CSV::Table mode:row row_count:4>
# table.size # => 3
# table.delete_if {|row| row['Name'].start_with?('b') }
# table.size # => 1
#
# Removes columns when the access mode is <tt>:col</tt>;
# calls the block with each column as a 2-element array
# containing the header and an \Array of column fields:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.by_col! # => #<CSV::Table mode:col row_count:4>
# table.headers.size # => 2
# table.delete_if {|column_data| column_data[1].include?('2') }
# table.headers.size # => 1
#
# Returns a new \Enumerator if no block is given:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.delete_if # => #<Enumerator: #<CSV::Table mode:col_or_row row_count:4>:delete_if>
def delete_if(&block)
return enum_for(__method__) { @mode == :row or @mode == :col_or_row ? size : headers.size } unless block_given?
if @mode == :row or @mode == :col_or_row # by index
@table.delete_if(&block)
else # by header
headers.each do |header|
delete(header) if yield([header, self[header]])
end
end
self # for chaining
end
include Enumerable
# :call-seq:
# table.each {|row_or_column| ... ) -> self
#
# Calls the block with each row or column; returns +self+.
#
# When the access mode is <tt>:row</tt> or <tt>:col_or_row</tt>,
# calls the block with each \CSV::Row object:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.by_row! # => #<CSV::Table mode:row row_count:4>
# table.each {|row| p row }
# Output:
# #<CSV::Row "Name":"foo" "Value":"0">
# #<CSV::Row "Name":"bar" "Value":"1">
# #<CSV::Row "Name":"baz" "Value":"2">
#
# When the access mode is <tt>:col</tt>,
# calls the block with each column as a 2-element array
# containing the header and an \Array of column fields:
# table.by_col! # => #<CSV::Table mode:col row_count:4>
# table.each {|column_data| p column_data }
# Output:
# ["Name", ["foo", "bar", "baz"]]
# ["Value", ["0", "1", "2"]]
#
# Returns a new \Enumerator if no block is given:
# table.each # => #<Enumerator: #<CSV::Table mode:col row_count:4>:each>
def each(&block)
return enum_for(__method__) { @mode == :col ? headers.size : size } unless block_given?
if @mode == :col
headers.each.with_index do |header, i|
yield([header, @table.map {|row| row[header, i]}])
end
else
@table.each(&block)
end
self # for chaining
end
# :call-seq:
# table == other_table -> true or false
#
# Returns +true+ if all each row of +self+ <tt>==</tt>
# the corresponding row of +other_table+, otherwise, +false+.
#
# The access mode does no affect the result.
#
# Equal tables:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# other_table = CSV.parse(source, headers: true)
# table == other_table # => true
#
# Different row count:
# other_table.delete(2)
# table == other_table # => false
#
# Different last row:
# other_table << ['bat', 3]
# table == other_table # => false
def ==(other)
return @table == other.table if other.is_a? CSV::Table
@table == other
end
# :call-seq:
# table.to_a -> array_of_arrays
#
# Returns the table as an \Array of \Arrays;
# the headers are in the first row:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.to_a # => [["Name", "Value"], ["foo", "0"], ["bar", "1"], ["baz", "2"]]
def to_a
array = [headers]
@table.each do |row|
array.push(row.fields) unless row.header_row?
end
array
end
# :call-seq:
# table.to_csv(**options) -> csv_string
#
# Returns the table as \CSV string.
# See {Options for Generating}[../CSV.html#class-CSV-label-Options+for+Generating].
#
# Defaults option +write_headers+ to +true+:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.to_csv # => "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
#
# Omits the headers if option +write_headers+ is given as +false+
# (see {Option +write_headers+}[../CSV.html#class-CSV-label-Option+write_headers]):
# table.to_csv(write_headers: false) # => "foo,0\nbar,1\nbaz,2\n"
#
# Limit rows if option +limit+ is given like +2+:
# table.to_csv(limit: 2) # => "Name,Value\nfoo,0\nbar,1\n"
def to_csv(write_headers: true, limit: nil, **options)
array = write_headers ? [headers.to_csv(**options)] : []
limit ||= @table.size
limit = @table.size + 1 + limit if limit < 0
limit = 0 if limit < 0
@table.first(limit).each do |row|
array.push(row.fields.to_csv(**options)) unless row.header_row?
end
array.join("")
end
alias_method :to_s, :to_csv
#
# Extracts the nested value specified by the sequence of +index+ or +header+ objects by calling dig at each step,
# returning nil if any intermediate step is nil.
#
def dig(index_or_header, *index_or_headers)
value = self[index_or_header]
if value.nil?
nil
elsif index_or_headers.empty?
value
else
unless value.respond_to?(:dig)
raise TypeError, "#{value.class} does not have \#dig method"
end
value.dig(*index_or_headers)
end
end
# :call-seq:
# table.inspect => string
#
# Returns a <tt>US-ASCII</tt>-encoded \String showing table:
# - Class: <tt>CSV::Table</tt>.
# - Access mode: <tt>:row</tt>, <tt>:col</tt>, or <tt>:col_or_row</tt>.
# - Size: Row count, including the header row.
#
# Example:
# source = "Name,Value\nfoo,0\nbar,1\nbaz,2\n"
# table = CSV.parse(source, headers: true)
# table.inspect # => "#<CSV::Table mode:col_or_row row_count:4>\nName,Value\nfoo,0\nbar,1\nbaz,2\n"
#
def inspect
inspected = +"#<#{self.class} mode:#{@mode} row_count:#{to_a.size}>"
summary = to_csv(limit: 5)
inspected << "\n" << summary if summary.encoding.ascii_compatible?
inspected
end
end
end