CODEWITHSUNDEEP
ruby
furkan karaaslan
furkan karaaslan

Reputation: 23

How can i read lines in a textfile with RUBY

I am new in ruby programming. I am trying to read a textfile line by line.

Here is my sample textfile:

john
doe
john_d
somepassword

Here is my code:

f = File.open('input.txt', 'r')
a = f.readlines
n = a[0]
s = a[1]
u = a[2]
p = a[3]
str = "<user><name=\"#{n}\" surname=\"#{s}\" username=\"#{u}\" password=\"#{p}\"/></user>"
File.open('result.txt', 'w') { |file| file.print(str) }

The output should look like this:

<user><name="john" surname="doe" username="john_d" password="somepassword"/></user>

But the result.txt looks like this. It includes newline character for every line:

<user><name="john
" surname="doe
" username="john_d
" password="somepassword"/></user>

How can i correct this?

Upvotes: 2

Views: 187

Answers (4)

Cary Swoveland
Cary Swoveland

Reputation: 110665

FName = 'temp'

File.write FName, "john
doe
john_d
somepassword"
  #=> 28

Here are two ways.

s = "<user><name=\"%s\" surname=\"%s\" username=\"%s\" password=\"%s\"/></user>"

puts s % File.readlines(FName).map(&:chomp)
  # <user><name="john" surname="doe" username="john_d" password="somepassword"/></user>
puts s % File.read(FName).split("\n")
  # <user><name="john" surname="doe" username="john_d" password="somepassword"/></user>

See String#% and, as mentioned in that doc, Kernel#sprintf.

Upvotes: 0

Laszlo-JFLMTCO
Laszlo-JFLMTCO

Reputation: 13

As @iGian already mentioned, chomp is a good option to clean up your text. I am not sure which version of Ruby you are using, but here is the link to the official Ruby version 2.5 documentation on chomp just so you see how it is going to help you: https://ruby-doc.org/core-2.5.0/String.html#method-i-chomp

See the content of variable a after using chomp:

2.4.1 :001 > f = File.open('input.txt', 'r')
=> #<File:input.txt> 
2.4.1 :002 > a = f.readlines.map! {|line| line.chomp}
=> ["john", "doe", "john_d", "somepassword"]

Depending on how many other corner cases you expect to see from your input string, here is also another suggestion that can help you to clean up your strings: strip with link to its official documentation with examples: https://ruby-doc.org/core-2.5.0/String.html#method-i-strip

See the content of variable a after using strip:

2.4.1 :001 > f = File.open('input.txt', 'r')
=> #<File:input.txt> 
2.4.1 :002 > a = f.readlines.map! {|line| line.strip}
=> ["john", "doe", "john_d", "somepassword"]

Upvotes: 1

iGian
iGian

Reputation: 11183

As explained by spickermann, also just change line two into:

a = f.readlines.map! { |line| line.chomp }

Upvotes: 1

spickermann
spickermann

Reputation: 106792

It includes newline character for every line, because there is a newline character at the end of every line.

Just removed it when you don't need it:

n = a[0].gsub("\n", '')
s = a[1].gsub("\n", '')
# ...

Upvotes: 3

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