CODEWITHSUNDEEP
rubyhashstrip
Jake Simms
Jake Simms

Reputation: 21

Remove leading white space in Ruby hash value

I'm working on an example problem from Chris Pine's Learn to Program book and I'm having an issue removing white space in my hash values.

I start with a txt file that contains names and birthday information, like so: 

Christopher Alexander,  Oct  4, 1936
Christopher Lambert,    Mar 29, 1957
Christopher Lee,        May 27, 1922
Christopher Lloyd,      Oct 22, 1938
Christopher Pine,       Aug  3, 1976

Then I go through each line, split at the first comma, and then try to go through each key,value to strip the white space. 

birth_dates = Hash.new {}

File.open 'birthdays.txt', 'r' do |f|
  f.read.each_line do |line|
  name, date = line.split(/,/, 2)
  birth_dates[name] = date
  birth_dates.each_key { |a| birth_dates[a].strip! }
end

But nothing is getting stripped. 

{"Christopher Alexander"=>"  Oct  4, 1936", "Christopher Lambert"=>"    Mar 29, 1957", "Christopher Lee"=>"        May 27, 1922", "Christopher Lloyd"=>"      Oct 22, 1938", "Christopher Pine"=>"       Aug  3, 1976", "Christopher Plummer"=>"    Dec 13, 1927", "Christopher Walken"=>"     Mar 31, 1943", "The King of Spain"=>"      Jan  5, 1938"}

I've seen a handful of solutions for Arrays using .map - but this was the only hash example I came across. Any idea why it may not be working for me?

UPDATE: removed the redundant chomp as per sawa's comment.

Upvotes: 2

Views: 1223

Answers (2)

peter
peter

Reputation: 42192

For parsing comma delimited files i use CSV like this

def parse_birthdays(file='birthdays.txt', hash={})
  CSV.foreach(file, :converters=> lambda {|f| f ? f.strip : nil}){|name, date, year|hash[name] = "#{year}-#{date.gsub(/ +/,'-')}" }
  hash
end
parse_birthdays
# {"Christopher Alexander"=>"1936-Oct-4", "Christopher Lambert"=>"1957-Mar-29", "Christopher Lee"=>"1922-May-27", "Christopher Lloyd"=>"1938-Oct-22", "Christopher Pine"=>"1976-Aug-3"}

of if you need real date's you can drop the lambda

def parse_birthdays(file='birthdays.txt', hash={})
  CSV.foreach(file){|name, date, year|hash[name] = Date.parse("#{year}-#{date}")}
  hash
end
parse_birthdays
# {"Christopher Alexander"=>#<Date: 2014-10-04 ((2456935j,0s,0n),+0s,2299161j)>, "Christopher Lambert"=>#<Date: 2014-03-29 ((2456746j,0s,0n),+0s,2299161j)>, "Christopher Lee"=>#<Date: 2014-05-27 ((2456805j,0s,0n),+0s,2299161j)>, "Christopher Lloyd"=>#<Date: 2014-10-22 ((2456953j,0s,0n),+0s,2299161j)>, "Christopher Pine"=>#<Date: 2014-08-03 ((2456873j,0s,0n),+0s,2299161j)>}

Upvotes: 2

bjhaid
bjhaid

Reputation: 9762

I would write this

File.open 'birthdays.txt', 'r' do |f|
  f.read.each_line do |line|
  name, date = line.split(/,/, 2)
  birth_dates[name] = date.chomp
  birth_dates.each_key { |a| birth_dates[a].strip! }
end

as below:

File.open 'birthdays.txt', 'r' do |f|
  f.read.each_line do |line|
    name, date = line.split(/,/, 2)
    birth_dates[name] = date.chomp.strip
  end
end

or 

birth_dates = File.readlines('birthdays.txt').with_object({}) do |line,hsh|
  name, date = line.split(/,/, 2)
  hsh[name] = date.chomp.strip
end

Upvotes: 0

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