String#pad ?

[Jani Monoses]

Hello

is there a nicer way of padding a string to a power of two length than for example

data = data.ljust((data.length+3) & ~3)

this looks too much like C


Jani

 

[Andreas Schwarz]

Hello

is there a nicer way of padding a string to a power of two length than
for example

data = data.ljust((data.length+3) & ~3)

this looks too much like C

At least a bit more readable:
data.ljust(data.size + data.size % 2)

 

[Martin DeMello]

Hello

is there a nicer way of padding a string to a power of two length than for example

data = data.ljust((data.length+3) & ~3)

this looks too much like C

And doesn't even work

class Fixnum
def lg
self.to_s(2).length - 1
end
end

class String
def ljust_pow2
self.ljust(2 ** (self.length.lg + 1))
end
end

p "hello world".ljust_pow2

martin

 

[Robert Klemme]

Hello

is there a nicer way of padding a string to a power of two length than

for example

Did you mean to say "multiple of two"? 'Cause that's what your code seems
to be doing.

data = data.ljust((data.length+3) & ~3)

this looks too much like C

Different story but not necessarily nicer:

data << (" " * (data.length % 2))
data << (" " * ((data.length + 1) % 2))

If you really meant "power of two" a somewhat weired version:

data.ljust( ( "1" + data.length.to_s(2).gsub(/1/, '0') ).to_i( 2 ) )



robert

 

[Jani Monoses]

And doesn't even work

It does work the power of two is 4.That's why I said for example
Ok my question meant a generic power of two but pasted the line from an actual program, my
bad.

class Fixnum
def lg
self.to_s(2).length - 1
end
end

class String
def ljust_pow2
self.ljust(2 ** (self.length.lg + 1))
end
end

p "hello world".ljust_pow2

This is even more work that the line above

Jani

 

[Jani Monoses]

Did you mean to say "multiple of two"? 'Cause that's what your code seems

to be doing.

definitely my bad wording since I mislead both of you

I just thought that something out of the box to do this would be nice

String#pad and String#pad!

data.pad!(n) #pad data to next 2^n boundary

or maybe powers of two are two restrictive than make n actually mean that make the strings
length a multiple of n.

Jani

 

[Robert Klemme]

definitely my bad wording since I mislead both of you

I just thought that something out of the box to do this would be nice

String#pad and String#pad!

data.pad!(n) #pad data to next 2^n boundary

or maybe powers of two are two restrictive than make n actually mean that make the strings
length a multiple of n.

IMHO this application is not general enough. Also, the name #pad does by
no means imply that the length will be n*m after invocation. For the
general case there is already #ljust and #rjust. I'd vote against having
these methods with the functionality you propose in the std lib.

Regards

robert