Ruby

Front 1

How to print to screen?

Back 1

"puts "

"p " (also prints object type)

Front 2

How to output to screen without newline?

Back 2

print

Front 3

How to evaluate variable inside double quotes?

Back 3

use "test #{ variable}"

Front 4

How to open and close a file?

Back 4

aFile = File.new("filename", "mode")
# ... process the file
aFile.close

Front 5

How to read the first 20 characters in a file?

Back 5

sysread can be used to read the contents of a file

e.g. content = aFile.sysread(20)

Front 6

how to read the lines of a textfile?

Back 6

arr = IO.readlines("fileltest.txt")

Front 7

How to read lines with Ruby?

Back 7

File.open('test.txt').each_line{ |s|
puts s
}

or

File.foreach('test.txt') { |s|
puts s
}

close file

Front 8

What is the output?

def callBlock
yield
yield
end


callBlock { puts "In the block" }

Back 8

In the block
In the block

Front 9

What does this produce?

a = %w( ant bee cat dog elk ) # create an array
a.each { |animal| puts animal } # iterate over the contents

Back 9

ant
bee
cat
dog
elk

Front 10

What is the effect of this?

a = %w{ ant bee cat dog elk }

Back 10

an array of string with values e.g.

a[0] >> "ant"
a[3] >> "dog"