get remaing characters in a string

[Claus Guttesen]

Hi.

I need to get the last three characters in a string. I couldn't find a
function in the String class so I came up with this:

class Remainder

attr_writer :n

def initialize(t = "", n = 0)
@t = t.to_s
@n = n.to_i
end

def get
get_remaining_letters
end

private
def get_remaining_letters
s = @t.size
if s < @n
r = 0
else
r = s - @n
end

ft = @t.slice(r, @n)
end

end


t = Remainder.new("Guttesen", 5)
puts t.get
tesen
t.n = 4
puts t.get
esen

Did I reinvent the wheel or does it make sense to add it to String?

regards
Claus

 

[Daniel Finnie]

You can use String#[] with a Range instead:

"asdfhsdfabc"[-3..-1]

=> "abc"

or you can specify the length:

"asdfhsdfabc"[-3, 3]

=> "abc"

Negative numbers count from the end of the string. So basically the
strings length plus your negative number is the position from the start
of the string.

Dan

 

[dblack]

Hi.

I need to get the last three characters in a string. I couldn't find a
function in the String class so I came up with this:

class Remainder

attr_writer :n

def initialize(t = "", n = 0)
@t = t.to_s
@n = n.to_i
end

def get
get_remaining_letters
end

private
def get_remaining_letters
s = @t.size
if s < @n
r = 0
else
r = s - @n
end

ft = @t.slice(r, @n)
end

end


t = Remainder.new("Guttesen", 5)
puts t.get
tesen
t.n = 4
puts t.get
esen

Did I reinvent the wheel or does it make sense to add it to String?

You can index strings from the right with negative numbers:

"abcdef"[-3..-1] => "def"

I think that might be all you need.


David

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A. RUBY FOR RAILS by David A. Black (http://www.manning.com/black)
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A. Ruby Power and Light, LLC (http://www.rubypal.com)

 

[Claus Guttesen]

I need to get the last three characters in a string. I couldn't find a

function in the String class so I came up with this:

You can index strings from the right with negative numbers:

"abcdef"[-3..-1] => "def"

I think that might be all you need.

I see. Thank you very much for all the replies.

regards
Claus

 

[William James]

Hi.

I need to get the last three characters in a string. I couldn't find a
function in the String class so I came up with this:

class Remainder

attr_writer :n

def initialize(t = "", n = 0)
@t = t.to_s
@n = n.to_i
end

def get
get_remaining_letters
end

private
def get_remaining_letters
s = @t.size
if s < @n
r = 0
else
r = s - @n
end

ft = @t.slice(r, @n)
end

end


t = Remainder.new("Guttesen", 5)
puts t.get
tesen
t.n = 4
puts t.get
esen

Did I reinvent the wheel or does it make sense to add it to String?

regards
Claus

If the length of the string is less than 3,
the entire string will be returned.

s = "ab"
s[ /.{0,3}$/ ]
s[-3,3] || s