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I need a Ruby program that, given a file as parameter, returns a hash or array that gives the number of characters for each line.
How can I do this elegantly in Ruby ?
File.open('file_name').map(&:length)
Check this:
File.open('file_name').inject([]) do |counts, line|
counts << line.size
end
Take a note that it will also count new line characters.
For file with content
aa
aaaa
a
the result will be
[3, 5, 1]
If you don't want to count them, check this method String#chomp
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I want to get two value in one line without split function. Help me to solving this problem. Thank you!
If you want to assign 2 variables in one line you can do
def multiple_values
return 1, 2
end
x, y = multiple_values
# x = 1
# y = 2
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I have the following string:
aaaaaa; bbbbbbbb
cccccc; cccccccc
dddddd; dddddddd
I need to take different action in respect to different lines.
More precisely, I must do something-1 with the first line, something-2 with all the other, and something-3 with the last one. Pseudo code:
out.each_line { |ln|
if ln first
do somenthing-1
end
if ln others
do somenthing-2
end
if ln last
do somenthing-3
end
}
I find this alternative a bit more readable:
first, *middle, last = out.lines
do_something_1(first)
middle.each{|line| do_something_2(line) }
do_something_3(last)
How about:
lines = out.lines
do_something_1(lines.first)
lines[1..-2].each do |line|
do_something_2(line)
end
do_something_3(lines.last)
This code will do some action on the first line, some other action on all lines except the first and the last, and a third action on the last line.
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I'm a total novice in ruby, i came across this code in an article about a bug in gmail:
(0..0xFFFFFFFFFF).each do |i|
puts "#{"%010X" % i}"
end
it is supposed to generate an dictionary, but i can't figure out how it works
Thank You all!
The code iterates and prints all values from 0 to 0xFFFFFFFFFF Similar to how
(1..10).each do |i|
puts i
end
iterates and prints all values from 1 to 10.
For each value between 0 and 0xFFFFFFFFFF it simply prints out its current hex value:
0000000000
...
0000005E6A
0000005E6B
0000005E6C
0000005E6D
0000005E6E
0000005E6F
...
FFFFFFFFFF
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I have a Ruby narray automatically generated, which has this form: [x,y], where x and y are integers.
I want to transform [x,y] into this type of string:
"p\.x\.y"
I haven't succeeded in transforming it using a regular expression.
Regex is used to match patterns, not to generate strings.
To accomplish what you want, just use the splat operator with sprintf:
array = [1,2]
puts sprintf("p\\.%d\\.%d", *array)
This will output "p\.1\.2"
Alternative way:
x = [1,2]
puts "p\\.#{x[0]}\\.#{x[1]}" #=> p\.1\2
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I am trying to find a regex that does the following. Let's say I have a string in this form
wordcount = "THE:12 IT:3 TO:3".
which is a word and its frequency. I need a regex that can find for example THe, followed by :, followed by a number.
If you want all matches use the scan method:
mystring.scan(/\w+:\d+/)
Bonus if you are planning to make a hash:
Hash[mystring.scan(/(\w+):(\d+)/)]
# or, if you prefer to not use regexp:
Hash[x.split.map{|y| y.split(':')}]
You can do as below :
s = "THE:12 IT:3 TO:3"
p s.scan(/\w+:\d+/)
# >> ["THE:12", "IT:3", "TO:3"]