I am trying to parse multiple XML files then output them into CSV files to list out the proper rows and columns.
I was able to do so by processing one file at a time by defining the filename, and specifically output them into a defined output file name:
File.open('H:/output/xmloutput.csv','w')
I would like to write into multiple files and make their name the same as the XML filenames without hard coding it. I tried doing it multiple ways but have had no luck so far.
Sample XML:
<?xml version="1.0" encoding="UTF-8"?>
<record:root>
<record:Dataload_Request>
<record:name>Bob Chuck</record:name>
<record:Address_Data>
<record:Street_Address>123 Main St</record:Street_Address>
<record:Postal_Code>12345</record:Postal_Code>
</record:Address_Data>
<record:Age>45</record:Age>
</record:Dataload_Request>
</record:root>
Here is what I've tried:
require 'nokogiri'
require 'set'
files = ''
input_folder = "H:/input"
output_folder = "H:/output"
if input_folder[input_folder.length-1,1] == '/'
input_folder = input_folder[0,input_folder.length-1]
end
if output_folder[output_folder.length-1,1] != '/'
output_folder = output_folder + '/'
end
files = Dir[input_folder + '/*.xml'].sort_by{ |f| File.mtime(f)}
file = File.read(input_folder + '/' + files)
doc = Nokogiri::XML(file)
record = {} # hashes
keys = Set.new
records = [] # array
csv = ""
doc.traverse do |node|
value = node.text.gsub(/\n +/, '')
if node.name != "text" # skip these nodes: if class isnt text then skip
if value.length > 0 # skip empty nodes
key = node.name.gsub(/wd:/,'').to_sym
if key == :Dataload_Request && !record.empty?
records << record
record = {}
elsif key[/^root$|^document$/]
# neglect these keys
else
key = node.name.gsub(/wd:/,'').to_sym
# in case our value is html instead of text
record[key] = Nokogiri::HTML.parse(value).text
# add to our key set only if not already in the set
keys << key
end
end
end
end
# build our csv
File.open('H:/output/.*csv', 'w') do |file|
file.puts %Q{"#{keys.to_a.join('","')}"}
records.each do |record|
keys.each do |key|
file.write %Q{"#{record[key]}",}
end
file.write "\n"
end
print ''
print 'output files ready!'
print ''
end
I have been getting 'read memory': no implicit conversion of Array into String (TypeError) and other errors.
Here's a quick peer-review of your code, something like you'd get in a corporate environment...
Instead of writing:
input_folder = "H:/input"
input_folder[input_folder.length-1,1] == '/' # => false
Consider doing it using the -1 offset from the end of the string to access the character:
input_folder[-1] # => "t"
That simplifies your logic making it more readable because it's lacking unnecessary visual noise:
input_folder[-1] == '/' # => false
See [] and []= in the String documentation.
This looks like a bug to me:
files = Dir[input_folder + '/*.xml'].sort_by{ |f| File.mtime(f)}
file = File.read(input_folder + '/' + files)
files is an array of filenames. input_folder + '/' + files is appending an array to a string:
foo = ['1', '2'] # => ["1", "2"]
'/parent/' + foo # =>
# ~> -:9:in `+': no implicit conversion of Array into String (TypeError)
# ~> from -:9:in `<main>'
How you want to deal with that is left as an exercise for the programmer.
doc.traverse do |node|
is icky because it sidesteps the power of Nokogiri being able to search for a particular tag using accessors. Very rarely do we need to iterate over a document tag by tag, usually only when we're peeking at its structure and layout. traverse is slower so use it as a very last resort.
length is nice but isn't needed when checking whether a string has content:
value = 'foo'
value.length > 0 # => true
value > '' # => true
value = ''
value.length > 0 # => false
value > '' # => false
Programmers coming from Java like to use the accessors but I like being lazy, probably because of my C and Perl backgrounds.
Be careful with sub and gsub as they don't do what you're thinking they do. Both expect a regular expression, but will take a string which they do a escape on before beginning their scan.
You're passing in a regular expression, which is OK in this case, but it could cause unexpected problems if you don't remember all the rules for pattern matching and that gsub scans until the end of the string:
foo = 'wd:barwd:' # => "wd:barwd:"
key = foo.gsub(/wd:/,'') # => "bar"
In general I recommend people think a couple times before using regular expressions. I've seen some gaping holes opened up in logic written by fairly advanced programmers because they didn't know what the engine was going to do. They're wonderfully powerful, but need to be used surgically, not as a universal solution.
The same thing happens with a string, because gsub doesn't know when to quit:
key = foo.gsub('wd:','') # => "bar"
So, if you're looking to change just the first instance use sub:
key = foo.sub('wd:','') # => "barwd:"
I'd do it a little differently though.
foo = 'wd:bar'
I can check to see what the first three characters are:
foo[0,3] # => "wd:"
Or I can replace them with something else using string indexing:
foo[0,3] = ''
foo # => "bar"
There's more but I think that's enough for now.
You should use Ruby's CSV class. Also, you don't need to do any string matching or regex stuff. Use Nokogiri to target elements. If you know the node names in the XML will be consistent it should be pretty simple. I'm not exactly sure if this is the output you want, but this should get you in the right direction:
require 'nokogiri'
require 'csv'
def xml_to_csv(filename)
xml_str = File.read(filename)
xml_str.gsub!('record:','') # remove the record: namespace
doc = Nokogiri::XML xml_str
csv_filename = filename.gsub('.xml', '.csv')
CSV.open(csv_filename, 'wb' ) do |row|
row << ['name', 'street_address', 'postal_code', 'age']
row << [
doc.xpath('//name').text,
doc.xpath('//Street_Address').text,
doc.xpath('//Postal_Code').text,
doc.xpath('//Age').text,
]
end
end
# iterate over all xml files
Dir.glob('*.xml').each { |filename| xml_to_csv(filename) }
I am trying to ngram my database file. It works when I ngram a parsed string, but I do not know how to do the same for my database file.
I have the following code so far:
(hopefully I am in the right track)
require 'ngram'
require 'sqlite3'
ngram = NGram.new({
:size => 2,
:word_separator => " ",
:padchar => "_"
})
p ngram.parse('something')
# => ["__", "_t", "te", "es", "st", "t_", "__"]
p ngram.parse('test phrase')
db = SQLite3::Database.new("sample.db") #opens db
#ngram sample.db
Help is very much appreciated!
From the github code of ngram gem's parse method:
def parse(phrase)
words = phrase.split(#separator)
if words.length == 1
process(phrase)
else
words.map { |w| process(w) }
end
end
So, it's expecting a string object so that it can call String#split on it. That's why it works with your first example where you pass a string as an argument to the ngram.parse method.
I am not exactly sure what you want to accomplish here, but as long as you pass a string to the ngram.parse method, it would work. Or, at least, pass an argument that responds to the split method.
I'm taking a file and reading in it's contents and creating a hash based on newlines. I've been able to make a hash based on the contents of each line, but how can I create a hash based on the content of everything before the next blank newline? Below is what I have so far.
Input:
Title 49th parallel
URL http://artsweb.bham.ac.uk/
Domain artsweb.bham.ac.uk
Title ABAA booknet
URL http://abaa.org/
Domain abaa.org
Code:
File.readlines('A.cfg').each do |line|
unless line.strip.empty?
hash = Hash[*line.strip.split("\t")]
puts hash
end
puts "\n" if line.strip.empty?
end
Outputs:
{"Title"=>"49th parallel"}
{"URL"=>"http://artsweb.bham.ac.uk/"}
{"Domain"=>"artsweb.bham.ac.uk"}
{"Title"=>"ABAA booknet"}
{"URL"=>"http://abaa.org/"}
{"Domain"=>"abaa.org"}
Desired Output:
{"Title"=>"49th parallel", "URL"=>"http://artsweb.bham.ac.uk/", "Domain"=>"artsweb.bham.ac.uk"}
{"Title"=>"ABAA booknet", "URL"=>"http://abaa.org/", "Domain"=>"abaa.org"}
Modifying your existing code, this does what you want:
hash = {}
File.readlines('A.cfg').each do |line|
if line.strip.empty?
puts hash if not hash.empty?
hash = {}
puts "\n"
else
hash.merge!(Hash[*line.strip.split("\t")])
end
end
puts hash
You can likely simplify that depending on what you're actually doing with the data.
open('A.cfg', &:read)
.strip.split(/#$/{2,}/)
.map{|s| Hash[s.scan(/^(\S+)\s+(\S+)/)]}
gives
[
{
"Title" => "49th",
"URL" => "http://artsweb.bham.ac.uk/",
"Domain" => "artsweb.bham.ac.uk"
},
{
"Title" => "ABAA",
"URL" => "http://abaa.org/",
"Domain" => "abaa.org"
}
]
read the whole content of the file using read:
contents = ""
File.open('A.cfg').do |file|
contents = file.read
end
And then split the contents on two newline characters:
contents.split("\n\n")
And lastly, create a function pretty similar to what you already have to parse those chunks.
Please note that if you are working on windows it may happen that you need to split on a different sequence because of the carriage return character.
I read the documentation of url_encode.
Is there a table that tells me exactly which character is encoded to what, using url_encode?
ERB's url_encode can be tweaked:
def url_encode(s)
s.to_s.dup.force_encoding("ASCII-8BIT").gsub(%r[^a-zA-Z0-9_\-.]/) {
sprintf("%%%02X", $&.unpack("C")[0])
}
end
to:
def url_encode(s, regex=%r[^a-zA-Z0-9_\-.]/)
s.to_s.dup.force_encoding("ASCII-8BIT").gsub(regex) {
sprintf("%%%02X", $&.unpack("C")[0])
}
end
url_encode('pop', /./)
=> "%70%6F%70"
In addition, Ruby's CGI and URI modules have the ability to encode URLs, converting restricted characters to entities, so don't overlook their offerings.
For instance, escaping characters for URL parameters:
CGI.escape('http://www.example.com')
=> "http%3A%2F%2Fwww.example.com"
CGI.escape('<body><p>foo</p></body>')
=> "%3Cbody%3E%3Cp%3Efoo%3C%2Fp%3E%3C%2Fbody%3E"
Ruby CGI's escape also uses a small regex to figure out which characters should be escaped in a URL. This is the method's definition from the documentation:
def CGI::escape(string)
string.gsub(%r([^ a-zA-Z0-9_.-]+)/) do
'%' + $1.unpack('H2' * $1.bytesize).join('%').upcase
end.tr(' ', '+')
end
You also override that and change the regex, or expose it for your own use inside your redefinition of the method:
def CGI::escape(string, escape_regex=%r([^ a-zA-Z0-9_.-]+)/)
string.gsub(escape_regex) do
'%' + $1.unpack('H2' * $1.bytesize).join('%').upcase
end.tr(' ', '+')
end
URI.encode_www_form_component also does a similar encoding, the only differences in characters are * and :
URI.encode_www_form_component('<p>foo</p>')
=> "%3Cp%3Efoo%3C%2Fp%3E"
And, similarly to overriding CGI::escape, you can override the regex in URI.encode_www_form_component:
def self.encode_www_form_component(str, regex=%r[^*\-.0-9A-Z_a-z]/)
str = str.to_s
if HTML5ASCIIINCOMPAT.include?(str.encoding)
str = str.encode(Encoding::UTF_8)
else
str = str.dup
end
str.force_encoding(Encoding::ASCII_8BIT)
str.gsub!(regex, TBLENCWWWCOMP_)
str.force_encoding(Encoding::US_ASCII)
end
I'm generating some CSV output using Ruby's built-in CSV. Everything works fine, but the customer wants the name field in the output to have wrapping double-quotes so the output looks like the input file. For instance, the input looks something like this:
1,1.1.1.1,"Firstname Lastname",more,fields
2,2.2.2.2,"Firstname Lastname, Jr.",more,fields
CSV's output, which is correct, looks like:
1,1.1.1.1,Firstname Lastname,more,fields
2,2.2.2.2,"Firstname Lastname, Jr.",more,fields
I know CSV is doing the right thing by not double-quoting the third field just because it has embedded blanks, and wrapping the field with double-quotes when it has the embedded comma. What I'd like to do, to help the customer feel warm and fuzzy, is tell CSV to always double-quote the third field.
I tried wrapping the field in double-quotes in my to_a method, which creates a "Firstname Lastname" field being passed to CSV, but CSV laughed at my puny-human attempt and output """Firstname Lastname""". That is the correct thing to do because it's escaping the double-quotes, so that didn't work.
Then I tried setting CSV's :force_quotes => true in the open method, which output double-quotes wrapping all fields as expected, but the customer didn't like that, which I expected also. So, that didn't work either.
I've looked through the Table and Row docs and nothing appeared to give me access to the "generate a String field" method, or a way to set a "for field n always use quoting" flag.
I'm about to dive into the source to see if there's some super-secret tweaks, or if there's a way to monkey-patch CSV and bend it to do my will, but wondered if anyone had some special knowledge or had run into this before.
And, yes, I know I could roll my own CSV output, but I prefer to not reinvent well-tested wheels. And, I'm also aware of FasterCSV; That's now part of Ruby 1.9.2, which I'm using, so explicitly using FasterCSV buys me nothing special. Also, I'm not using Rails and have no intention of rewriting it in Rails, so unless you have a cute way of implementing it using a small subset of Rails, don't bother. I'll downvote any recommendations to use any of those ways just because you didn't bother to read this far.
Well, there's a way to do it but it wasn't as clean as I'd hoped the CSV code could allow.
I had to subclass CSV, then override the CSV::Row.<<= method and add another method forced_quote_fields= to make it possible to define the fields I want to force-quoting on, plus pull two lambdas from other methods. At least it works for what I want:
require 'csv'
class MyCSV < CSV
def <<(row)
# make sure headers have been assigned
if header_row? and [Array, String].include? #use_headers.class
parse_headers # won't read data for Array or String
self << #headers if #write_headers
end
# handle CSV::Row objects and Hashes
row = case row
when self.class::Row then row.fields
when Hash then #headers.map { |header| row[header] }
else row
end
#headers = row if header_row?
#lineno += 1
#do_quote ||= lambda do |field|
field = String(field)
encoded_quote = #quote_char.encode(field.encoding)
encoded_quote +
field.gsub(encoded_quote, encoded_quote * 2) +
encoded_quote
end
#quotable_chars ||= encode_str("\r\n", #col_sep, #quote_char)
#forced_quote_fields ||= []
#my_quote_lambda ||= lambda do |field, index|
if field.nil? # represent +nil+ fields as empty unquoted fields
""
else
field = String(field) # Stringify fields
# represent empty fields as empty quoted fields
if (
field.empty? or
field.count(#quotable_chars).nonzero? or
#forced_quote_fields.include?(index)
)
#do_quote.call(field)
else
field # unquoted field
end
end
end
output = row.map.with_index(&#my_quote_lambda).join(#col_sep) + #row_sep # quote and separate
if (
#io.is_a?(StringIO) and
output.encoding != raw_encoding and
(compatible_encoding = Encoding.compatible?(#io.string, output))
)
#io = StringIO.new(#io.string.force_encoding(compatible_encoding))
#io.seek(0, IO::SEEK_END)
end
#io << output
self # for chaining
end
alias_method :add_row, :<<
alias_method :puts, :<<
def forced_quote_fields=(indexes=[])
#forced_quote_fields = indexes
end
end
That's the code. Calling it:
data = [
%w[1 2 3],
[ 2, 'two too', 3 ],
[ 3, 'two, too', 3 ]
]
quote_fields = [1]
puts "Ruby version: #{ RUBY_VERSION }"
puts "Quoting fields: #{ quote_fields.join(', ') }", "\n"
csv = MyCSV.generate do |_csv|
_csv.forced_quote_fields = quote_fields
data.each do |d|
_csv << d
end
end
puts csv
results in:
# >> Ruby version: 1.9.2
# >> Quoting fields: 1
# >>
# >> 1,"2",3
# >> 2,"two too",3
# >> 3,"two, too",3
This post is old, but I can't believe no one thought of this.
Why not do:
csv = CSV.generate :quote_char => "\0" do |csv|
where \0 is a null character, then just add quotes to each field where they are needed:
csv << [product.upc, "\"" + product.name + "\"" # ...
Then at the end you can do a
csv.gsub!(/\0/, '')
I doubt if this will help the customer feeling warm and fuzzy after all this time, but this seems to work:
require 'csv'
#prepare a lambda which converts field with index 2
quote_col2 = lambda do |field, fieldinfo|
# fieldinfo has a line- ,header- and index-method
if fieldinfo.index == 2 && !field.start_with?('"') then
'"' + field + '"'
else
field
end
end
# specify above lambda as one of the converters
csv = CSV.read("test1.csv", :converters => [quote_col2])
p csv
# => [["aaa", "bbb", "\"ccc\"", "ddd"], ["fff", "ggg", "\"hhh\"", "iii"]]
File.open("test1.txt","w"){|out| csv.each{|line|out.puts line.join(",")}}
CSV has a force_quotes option that will force it to quote all fields (it may not have been there when you posted this originally). I realize this isn't exactly what you were proposing, but it's less monkey patching.
2.1.0 :008 > puts CSV.generate_line [1,'1.1.1.1','Firstname Lastname','more','fields']
1,1.1.1.1,Firstname Lastname,more,fields
2.1.0 :009 > puts CSV.generate_line [1,'1.1.1.1','Firstname Lastname','more','fields'], force_quotes: true
"1","1.1.1.1","Firstname Lastname","more","fields"
The drawback is that the first integer value ends up listed as a string, which changes things when you import into Excel.
It's been a long time, but since the CSV library has been patched, this might help someone if they're now facing this issue:
require 'csv'
# puts CSV::VERSION # this should be 3.1.9+
headers = ['id', 'ip', 'name', 'foo', 'bar']
data = [
[1, '1.1.1.1','Firstname Lastname','more','fields'],
[2, '2.2.2.2','Firstname Lastname, Jr.','more','fields']
]
quoter = Proc.new do |field, field_meta|
# the index starts at zero, that's why the third field would be 2:
field = '"' + field + '"' if field_meta.index == 2 && fields_meta.index > 1
field = '"' + field + '"' if field.is_a?(String) && field.include?(',')
# ^ CSV format needs to escape fields containing comma(s): ,
field
end
file = CSV.generate(headers: true, quote_char: '', write_converters: quoter) do |csv|
csv << headers
data.each { |row| csv << row }
end
puts file
the output would be:
id,ip,name,foo,bar
1,1.1.1.1,"Firstname Lastname",more,fields
2,2.2.2.2,"Firstname Lastname, Jr.",more,fields
It doesn't look like there's any way to do this with the existing CSV implementation short of monkey-patching/rewriting it.
However, assuming you have full control over the source data, you could do this:
Append a custom string including a comma (i.e. one that would never be naturally found in the data) to the end of the field in question for each row; maybe something like "FORCE_COMMAS,".
Generate the CSV output.
Now that you have CSV output with quotes on every row for your field, remove the custom string: csv.gsub!(/FORCE_COMMAS,/, "")
Customer feels warm and fuzzy.
CSV has changed a bit in Ruby 2.1 as mentioned by #jwadsack, however here's an working version of #the-tin-man's MyCSV. Bit modified, you set the forced_quote_fields via options.
MyCSV.generate(forced_quote_fields: [1]) do |_csv|...
The modified code
require 'csv'
class MyCSV < CSV
def <<(row)
# make sure headers have been assigned
if header_row? and [Array, String].include? #use_headers.class
parse_headers # won't read data for Array or String
self << #headers if #write_headers
end
# handle CSV::Row objects and Hashes
row = case row
when self.class::Row then row.fields
when Hash then #headers.map { |header| row[header] }
else row
end
#headers = row if header_row?
#lineno += 1
output = row.map.with_index(&#quote).join(#col_sep) + #row_sep # quote and separate
if #io.is_a?(StringIO) and
output.encoding != (encoding = raw_encoding)
if #force_encoding
output = output.encode(encoding)
elsif (compatible_encoding = Encoding.compatible?(#io.string, output))
#io.set_encoding(compatible_encoding)
#io.seek(0, IO::SEEK_END)
end
end
#io << output
self # for chaining
end
def init_separators(options)
# store the selected separators
#col_sep = options.delete(:col_sep).to_s.encode(#encoding)
#row_sep = options.delete(:row_sep) # encode after resolving :auto
#quote_char = options.delete(:quote_char).to_s.encode(#encoding)
#forced_quote_fields = options.delete(:forced_quote_fields) || []
if #quote_char.length != 1
raise ArgumentError, ":quote_char has to be a single character String"
end
#
# automatically discover row separator when requested
# (not fully encoding safe)
#
if #row_sep == :auto
if [ARGF, STDIN, STDOUT, STDERR].include?(#io) or
(defined?(Zlib) and #io.class == Zlib::GzipWriter)
#row_sep = $INPUT_RECORD_SEPARATOR
else
begin
#
# remember where we were (pos() will raise an exception if #io is pipe
# or not opened for reading)
#
saved_pos = #io.pos
while #row_sep == :auto
#
# if we run out of data, it's probably a single line
# (ensure will set default value)
#
break unless sample = #io.gets(nil, 1024)
# extend sample if we're unsure of the line ending
if sample.end_with? encode_str("\r")
sample << (#io.gets(nil, 1) || "")
end
# try to find a standard separator
if sample =~ encode_re("\r\n?|\n")
#row_sep = $&
break
end
end
# tricky seek() clone to work around GzipReader's lack of seek()
#io.rewind
# reset back to the remembered position
while saved_pos > 1024 # avoid loading a lot of data into memory
#io.read(1024)
saved_pos -= 1024
end
#io.read(saved_pos) if saved_pos.nonzero?
rescue IOError # not opened for reading
# do nothing: ensure will set default
rescue NoMethodError # Zlib::GzipWriter doesn't have some IO methods
# do nothing: ensure will set default
rescue SystemCallError # pipe
# do nothing: ensure will set default
ensure
#
# set default if we failed to detect
# (stream not opened for reading, a pipe, or a single line of data)
#
#row_sep = $INPUT_RECORD_SEPARATOR if #row_sep == :auto
end
end
end
#row_sep = #row_sep.to_s.encode(#encoding)
# establish quoting rules
#force_quotes = options.delete(:force_quotes)
do_quote = lambda do |field|
field = String(field)
encoded_quote = #quote_char.encode(field.encoding)
encoded_quote +
field.gsub(encoded_quote, encoded_quote * 2) +
encoded_quote
end
quotable_chars = encode_str("\r\n", #col_sep, #quote_char)
#quote = if #force_quotes
do_quote
else
lambda do |field, index|
if field.nil? # represent +nil+ fields as empty unquoted fields
""
else
field = String(field) # Stringify fields
# represent empty fields as empty quoted fields
if field.empty? or
field.count(quotable_chars).nonzero? or
#forced_quote_fields.include?(index)
do_quote.call(field)
else
field # unquoted field
end
end
end
end
end
end