ruby-examination

1. heredoc

use << as input redirection.

example

puts <<'EOF'  # EOF is a single word ,must same as the end singnal
hello,  
ruby  
EOF           # should same as the word after << ,any word is ok
here 

result

hello,/nruby/n

2. step, times, upto, downto methods

step

object.step(limit, stepon){ |x|
do something...
}
when loop (object + stepon * index) > limit ,exit the loop index from 0, add 1 step

1.2.step(4.8, 1.4){|x|    # 1
puts x
}

result

1.2
2.599999999996
4.0

times

TODO

3. Array product and transpose

example

[1,3,4].product([5,8])

result

[[1,5],[1,8],[3,5],[3,8],[4,5],[4,8]]

example

[[1,5],[1,8],[3,5],[3,8],[4,5],[4,8]].transpose

result

[[1,1,3,3,4,4],[5,8,5,8,5,8]]