How to write this correctly?

R

Ruby Newbee

Hi,

In python this is right:
'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 `<main>'



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

Ruby Newbee

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

"Hello, %s %s" %(["Matz!","again"])
=3D> "Hello, Matz! again"
 
W

W. James

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

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



Hi,

In python this is right:

'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 `<main>'



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"

--
 
H

Hal Fulton

[Note: parts of this message were removed to make it a legal post.]
"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
 
B

Bertram Scharpf

Hi,

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

Rick DeNatale

Hi,

Am Montag, 14. Dez 2009, 16:05:54 +0900 schrieb Ruby Newbee:
Oh sorry I have found that.
need to convert the arguments to an array.

"Hello, %s %s" %(["Matz!","again"])
=3D> "Hello, Matz! again"

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

=A0%("Matz!","again")

for

=A0%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")
=3D> "\"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 o=
ne.

Perhaps a subtle Ruby parsing/lexing bug.
What you do is applying the mod(%) operator to a string:

=A0str % array
=A0"%s %d %f" % [ "hi", 33, 0.618] =A0 =A0 #=3D> "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.

--=20
Rick DeNatale

Blog: http://talklikeaduck.denhaven2.com/
Twitter: http://twitter.com/RickDeNatale
WWR: http://www.workingwithrails.com/person/9021-rick-denatale
LinkedIn: http://www.linkedin.com/in/rickdenatale
 

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