How to write this correctly?

Ruby
#1

Hi,

In python this is right:

“Hello, %s %s” %(“Matz!”,“again”)
‘Hello, Matz! again’

But in ruby it will get wrong:

“Hello, %s %s” %(“Matz!”,“again”)
SyntaxError: (irb):39: syntax error, unexpected ‘,’, expecting ‘)’
“Hello, %s %s” %(“Matz!”,“again”)
^
from /usr/bin/irb:12:in `’

So what’s the correct syntax for this case?
Thanks.

#2

Oh sorry I have found that.
need to convert the arguments to an array.

“Hello, %s %s” %([“Matz!”,“again”])
=> “Hello, Matz! again”

#3

Ruby N. wrote:

Hi,
SyntaxError: (irb):39: syntax error, unexpected ‘,’, expecting ‘)’
“Hello, %s %s” %(“Matz!”,“again”)
            ^
    from /usr/bin/irb:12:in `’

So what’s the correct syntax for this case?
Thanks.

“Hello, %s %s” % [“Matz!”, “again”]
==>“Hello, Matz! again”
“Hello, %s %s” % %w(Matz! again)
==>“Hello, Matz! again”

#4

Hi,

Am Montag, 14. Dez 2009, 16:05:54 +0900 schrieb Ruby N.:

Oh sorry I have found that.
need to convert the arguments to an array.

“Hello, %s %s” %([“Matz!”,“again”])
=> “Hello, Matz! again”

Be aware that % is interpreted as an operator because of the
string in front of it. There is also a shortcut

%(“Matz!”,“again”)

for

%Q(“Matz!”,“again”)

which would be a string.

What you do is applying the mod(%) operator to a string:

str % array
“%s %d %f” % [ “hi”, 33, 0.618] #=> “hi 33 0.618000”

Omit the parenthesis and write

“Hello, %s %s” % [“Matz!”,“again”]

or even

“Hello, %s %s” % %w(Matz! again)

Bertram

#5

“Hello, %s %s” % [“Matz!”, “again”]
==>“Hello, Matz! again”
“Hello, %s %s” % %w(Matz! again)
==>“Hello, Matz! again”

Or for those who prefer:

str = sprintf(“Hello, %s %s”, “Matz!”, “again”)

Or variations such as:

array = %w[Matz! again]
sprintf(“Hello, %s %s”, *array)

Or of course, printf will format and output as well:

printf(“Hello, %s %s”, “Matz!”, “again”)

Cheers,
Hal

#6

On Mon, Dec 14, 2009 at 4:59 AM, Bertram S.
[email protected] wrote:

string in front of it. There is also a shortcut

%(“Matz!”,“again”)

for

%Q(“Matz!”,“again”)

which would be a string.

Actually, I’m not sure how that % before the ( is being seen by the
parser.

By itself

%(“Matz!”,“again”)
=> ““Matz!”,“again””

For either Ruby 1.8.6 or 1.9.

%( should interpret everything up to the the matching ) as part of a
string including the "'s and the , I’m not sure why it doesn’t do the
same thing as:

“Hello, %s %s” % ““Matz!”,“again””
ArgumentError: too few arguments
from (irb):3:in `%’
from (irb):3

Since the format string needs two substitutions and we are only giving
it one.

Perhaps a subtle Ruby parsing/lexing bug.

What you do is applying the mod(%) operator to a string:

str % array
“%s %d %f” % [ “hi”, 33, 0.618] #=> “hi 33 0.618000”

No, this is sending the message % to the string. String#% is NOT mod,
the documentation (informally calls it format) and directs you to
Kernel#sprintf for further explanation.

Other that sharing the name :’&’ with the methods in the various
Numeric subclasses, there’s no meaning of mod.

–
Rick DeNatale

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