Learn Ruby

Thursday, July 06, 2006

quick and dirty codes for my bio info program

class Gene
  def initialize(seq, info)
    @seq = seq
    @info = info
    @ei_marks = [0] + srch_ei_recursively(0)
  end
  
  def ex_N
    @ei_marks.size/2 + 1
  end
  
  def in_N
    @ei_makrs.size/2
  end
  
  def exon(index)
    if (index*2) < @ei_marks.size - 1
      @seq[@ei_marks[index*2]...@ei_marks[index*2 + 1]]      
    else
      @seq[@ei_marks[index*2]...@seq.size]
    end
  end
  
  def intron(index)
    @seq[(@ei_marks[index*2 + 1])...(@ei_marks[index*2 + 2])]
  end
  def test
    @ei_marks
  end
  private
  def srch_ei_recursively(beg)
    beg_value = @seq[beg].to_i
    inter_value = 96.5 # the value of 'Z' is 96
    for i in beg...@seq.size
      if (((beg_value - inter_value)*(@seq[i].to_i - inter_value)) < 0)
        return [i] + srch_ei_recursively(i)
      end
    end
    return []
  end  
  # end of private methods
  
end

posted by Larme # 6:58 PM 0 Comments

Wednesday, July 05, 2006

String#delete

这个method接受的参数多于一个时，只要有一个参数不存在于目标string里，任何动作就都不会执行。看例子比较容易明白。

irb(main):001:0> a = "he l lo  !"
=> "he l lo  !"
irb(main):002:0> a.delete!(" ", "a")
=> nil
irb(main):003:0> a
=> "he l lo  !"
irb(main):004:0> a.delete!(" ")
=> "hello!"
irb(main):005:0>

所以执行String#delete要么逐个删除，要么用String#include?检查一下。

另外'\n'与"\n"的区别在这里也有体现：

irb(main):001:0> "he ll o\n".delete('\n')
=> "he ll o\n"
irb(main):002:0> "he ll o\n".delete("\n")
=> "he ll o"
irb(main):003:0> printf('\n')
\n=> nil
irb(main):004:0> printf("\n")

=> nil
irb(main):005:0>

posted by Larme # 7:59 AM 0 Comments

Integer#chr

若是使用getc, readchar读取IO的字符，结果会是一个0~255的整数。若想将其转换成字符，可以用chr method.比如

irb(main):001:0> 98.chr
=> "b"

reference

posted by Larme # 4:32 AM 0 Comments

Tuesday, July 04, 2006

如何控制output的格式

最简单的是用 printf，格式使用起来跟C的语法一样
如下面的语句

testfile = File.new("testfile", "w")
a = 5
for i in 1..10 do
     testfile.printf("%0#{a}d \n", i)
     end

那么得到的结果就是

$cat testfile
00001
00002
00003
00004
00005
00006
00007
00008
00009
00010

注意设置宽度是用#{a}把变量a的值传递到字符串内

posted by Larme # 4:28 AM 0 Comments