Search through a csv file

luislavena · November 15, 2011, 9:09am

i have a person details csv file. I am trying to write a code to search
for a particular person based on his first and last name. I wrote the
code to search for single value but i am not sure how to search through
a table with multiple keys. My code is:

def load_xvid_file(“person.csv”, “r”) do |csv|)
@firstnames = []
@lastnames = []
csv_file = CSV.read(person.csv)
csv_contents.shift
csv_contents.each do |row|
@firstnames << row[0]
end
csv_contents.each do |row|
@lastnames << row[1]
end
@firstnames.each { |f| f.downcase! }
@lastnames.each { |l| l.downcase! }
end

def search_for_person(fname,lname)
fname = fname.downcase
lname = lname.downcase
puts

if @firstnames.include?(fname)
if @lastnames.include?(lname)
puts “#{fname} #{lname} found!”
else
puts “#{fname} #{lname} not found!”
end
prompt
end

this code doesn’t work. can you help me debug this.

Thank you loads in advance.

Regards,
Akshath

akshathakshu · November 15, 2011, 10:10am

On Tue, Nov 15, 2011 at 3:09 AM, Aksh A. [email protected]
wrote:

csv_contents.shift
csv_contents.each do |row|
@firstnames << row[0]
end
csv_contents.each do |row|
@lastnames << row[1]
end
Where have you assigned csv_contents? I’m guessing that you want to
pass the name of the file to open with def load_xvid_file. If that is
the case you should be doing
def load_xvid_file(file_to_open)
#stuff
end

@firstnames.each { |f| f.downcase! }
@lastnames.each { |l| l.downcase! }
end

def search_for_person(fname,lname)
fname = fname.downcase
lname = lname.downcase
puts
What is the puts for?
if @firstnames.include?(fname)
if @lastnames.include?(lname)
You should take a look at Enumerable#select or Array#select if you use
1.9’s default CSV class you will get back an array of arrays or you
can just use an each block. Although I am sure there is a more
compact way of searching a nested array.
puts “#{fname} #{lname} found!”
else
puts “#{fname} #{lname} not found!”
end
prompt
end
Unless I am missing something you need one more end in search_for

What is the error message that you get? In the future always include
a bit about the error you get when you run into problems. Hope this
helps.

akshathakshu · November 15, 2011, 8:15pm

On Tue, Nov 15, 2011 at 05:09:46PM +0900, Aksh A. wrote:

i have a person details csv file. I am trying to write a code to search
for a particular person based on his first and last name. I wrote the
code to search for single value but i am not sure how to search through
a table with multiple keys. My code is:

The CSV library that ships with Ruby can help quite a bit with this.
I assume that you are on 1.9, or using FasterCSV with 1.8

https://gist.github.com/1367985

The meat of which is:

search_criteria =  { 'name' => 'Ruby', 'sex' => 'girl' }
options = { :headers => :first_row, :converters => [ :numeric ] }

CSV.open( csv_fname, "r", options ) do |csv|

  # Since CSV includes Enumerable we can use 'find_all'
  # which will return all the elements of the Enumerble for
  # which the block returns true

  matches = csv.find_all do |row|
    match = true
    search_criteria.keys.each do |key|
      match = match && ( row[key] == search_criteria[key] )
    end
    match
  end
end

enjoy,

-jeremy

akshathakshu · November 16, 2011, 7:02am

On Wed, Nov 16, 2011 at 06:15:33AM +0900, Yossef M. wrote:

search_criteria.all? { |k, v| row[k] == v }

I actually had to check out Hash#all? to see if it worked the way I
thought. I’ve never had a reason to use it before.

Ah, learning something new, loving it :-).

akshathakshu · November 15, 2011, 10:16pm

On Nov 15, 2:14pm, Jeremy H. [email protected] wrote:

matches = csv.find_all do |row|
match = true
search_criteria.keys.each do |key|
match = match && ( row[key] == search_criteria[key] )
end
match
end

search_criteria.all? { |k, v| row[k] == v }

I actually had to check out Hash#all? to see if it worked the way I
thought. I’ve never had a reason to use it before.

akshathakshu · December 29, 2011, 9:15am

-----Messaggio originale-----
Da: Jeremy H. [mailto:[email protected]]
Inviato: mercoled 16 novembre 2011 07:02
A: ruby-talk ML
Oggetto: Re: search through a csv file

On Wed, Nov 16, 2011 at 06:15:33AM +0900, Yossef M. wrote:

thought. I’ve never had a reason to use it before.
Ah, learning something new, loving it :-).

–

Jeremy H. [email protected]

–
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akshathakshu · December 29, 2011, 9:34am

-----Messaggio originale-----
Da: Aksh A. [mailto:[email protected]]
Inviato: marted 15 novembre 2011 09:10
A: ruby-talk ML
Oggetto: search through a csv file

i have a person details csv file. I am trying to write a code to search
for
a particular person based on his first and last name. I wrote the code
to
search for single value but i am not sure how to search through a table
with
multiple keys. My code is: