Printf inside a string

ruby-talk
1

Hi,
This is a pretty simple question. I need to do a "printf" of some
numbers inside a string. I just can't figure out how to express a long
string that has that "printf" inside it, because the printf statement
itself has quotes, too. I just need the number to end up being
zero-padded to 3 characters. So, for "3," I want "003."

number = "3"

puts "stuff, printf "%.3d\n", #{number}"
      ...compile error...

Thanks,
Peter

···

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2

stuff, 003
=> nil

Hope that helps.

James Edward Gray II

···

On Mar 1, 2007, at 9:39 AM, Peter Bailey wrote:

Hi,
This is a pretty simple question. I need to do a "printf" of some
numbers inside a string. I just can't figure out how to express a long
string that has that "printf" inside it, because the printf statement
itself has quotes, too. I just need the number to end up being
zero-padded to 3 characters. So, for "3," I want "003."

number = "3"

puts "stuff, printf "%.3d\n", #{number}"

>> printf "stuff, %.3d\n", number

3

Peter Bailey wrote:

Hi,
This is a pretty simple question. I need to do a "printf" of some
numbers inside a string. I just can't figure out how to express a long
string that has that "printf" inside it, because the printf statement
itself has quotes, too. I just need the number to end up being
zero-padded to 3 characters. So, for "3," I want "003."

number = "3"

puts "stuff, printf "%.3d\n", #{number}"
      ...compile error...

Thanks,
Peter

Hi Peter,

I don't quite get what are you trying to do, but I advice to do that:

printf("stuff, %.3d\n",number)

That should be all.

Alin.

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4

I think what you were trying to do is:

  number = "3"
  puts "stuff, #{sprintf "%.3d", number}"

Note that sprintf(..) is like printf(..) but returns the result as a string
value, rather than sending it to stdout. Then #{} lets you insert an
arbitary expression inside another string.

But as pointed out by others, you can do this in one go as

  printf "stuff, %.3d\n", number

HTH,

Brian.

···

On Fri, Mar 02, 2007 at 12:39:13AM +0900, Peter Bailey wrote:

This is a pretty simple question. I need to do a "printf" of some
numbers inside a string. I just can't figure out how to express a long
string that has that "printf" inside it, because the printf statement
itself has quotes, too.

5

alternatively

puts "stuff, #{ '%.3d' % number }"

-a

···

On Fri, 2 Mar 2007, James Edward Gray II wrote:

On Mar 1, 2007, at 9:39 AM, Peter Bailey wrote:

Hi,
This is a pretty simple question. I need to do a "printf" of some
numbers inside a string. I just can't figure out how to express a long
string that has that "printf" inside it, because the printf statement
itself has quotes, too. I just need the number to end up being
zero-padded to 3 characters. So, for "3," I want "003."

number = "3"

puts "stuff, printf "%.3d\n", #{number}"

printf "stuff, %.3d\n", number

stuff, 003
=> nil

Hope that helps.

--
be kind whenever possible... it is always possible.
- the dalai lama

6

Brian Candler wrote:

···

On Fri, Mar 02, 2007 at 12:39:13AM +0900, Peter Bailey wrote:

This is a pretty simple question. I need to do a "printf" of some
numbers inside a string. I just can't figure out how to express a long
string that has that "printf" inside it, because the printf statement
itself has quotes, too.

I think what you were trying to do is:

  number = "3"
  puts "stuff, #{sprintf "%.3d", number}"

Note that sprintf(..) is like printf(..) but returns the result as a
string
value, rather than sending it to stdout. Then #{} lets you insert an
arbitary expression inside another string.

But as pointed out by others, you can do this in one go as

  printf "stuff, %.3d\n", number

HTH,

Brian.

Thanks to all you guys. I'll probably use sprintf, actually, now that
I'm clear about how it's used.

Cheers.

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