Programming Forums > Script Programming > Python

kurt · Feb 28th, 2007, 11:20 AM

I'm having trouble printing out tuples.

Say, I have a function "joker":

def joker(*args):
print "%s" %args

and I call the function with:

(Toggle Plain Text)

joker("dad", "dasdsad", "dasdas")

I get:

(Toggle Plain Text)

ERROR: not all arguments converted during string formatting

Well, putting

(Toggle Plain Text)

print args

would print the whole tuple, but what i'm trying to acheive is printing the tuple without the parenthesis. I'm ok with the comma.

Can get this to work. Can you guys help?

Thanks in advance.

p/s: I'm also wondering what does the red part do?

(Toggle Plain Text)

command="dasdasd"
args = ("dasdas","dasdas")
print(command%args)

Arevos · Feb 28th, 2007, 12:53 PM

String formatting in Python either uses a single variable:

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"Hello %s" % "World"   =>   "Hello World"

Or a tuple of variables:

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"Name: %s, age: %d" % ("Frank", 27)    =>   "Name: Frank, age: 27"

This is why you can't print out the tuple directly.

The print command uses the repr function to show a human-readable representation of the data structure. So this:

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print (1, 2)

Is equivalent to:

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print "%s" % repr((1, 2))

In order to get some other representation of the tuple, such as without the brackets, you need to convert it into a string. The easiest way to do this is via the join method:

(Toggle Plain Text)

tup = ("Hello", "World")
print ":".join(tup)    =>    Hello:World

The only problem with this is that if your tuple contains non-strings, they won't join together. So you first have to convert them, either by a generator comprehension:

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tup = ("Hello", 1)
print ", ".join(str(x) for x in tup)    =>    Hello, 1

Or via map, which applies a function to each element:

(Toggle Plain Text)

tup = ("Hello", 1)
print ", ".join(map(str, tup))   =>    Hello, 1

If you want the representation of the object, use repr instead of str:

(Toggle Plain Text)

tup = ("Hello", 1)
print ", ".join(map(repr, tup))    =>    "Hello", 1

Dietrich · Mar 1st, 2007, 6:03 PM

How about something like this:

(Toggle Plain Text)

def joker(*args):
    for item in args:
        print "%s" % item,

joker("dad", "dasdsad", "dasdas")

Feb 28th, 2007, 11:20 AM	#1
kurt Programmer Join Date: Oct 2005 Posts: 65 Rep Power: 3	String formatting with tuples I'm having trouble printing out tuples. Say, I have a function "joker": (Toggle Plain Text) def joker(args): print "%s" %args def joker(args): print "%s" %args and I call the function with: (Toggle Plain Text) joker("dad", "dasdsad", "dasdas") joker("dad", "dasdsad", "dasdas") I get: (Toggle Plain Text) ERROR: not all arguments converted during string formatting ERROR: not all arguments converted during string formatting Well, putting (Toggle Plain Text) print args print args would print the whole tuple, but what i'm trying to acheive is printing the tuple without the parenthesis. I'm ok with the comma. Can get this to work. Can you guys help? Thanks in advance. p/s: I'm also wondering what does the red part do? (Toggle Plain Text) command="dasdasd" args = ("dasdas","dasdas") print(command%args) command="dasdasd" args = ("dasdas","dasdas") print(command%args) Last edited by kurt; Feb 28th, 2007 at 11:55 AM.

Feb 28th, 2007, 12:53 PM	#2
Arevos Programming Guru Join Date: Aug 2005 Location: England Posts: 1,499 Rep Power: 4	String formatting in Python either uses a single variable: (Toggle Plain Text) "Hello %s" % "World" => "Hello World" "Hello %s" % "World" => "Hello World" Or a tuple of variables: (Toggle Plain Text) "Name: %s, age: %d" % ("Frank", 27) => "Name: Frank, age: 27" "Name: %s, age: %d" % ("Frank", 27) => "Name: Frank, age: 27" This is why you can't print out the tuple directly. The print command uses the repr function to show a human-readable representation of the data structure. So this: (Toggle Plain Text) print (1, 2) print (1, 2) Is equivalent to: (Toggle Plain Text) print "%s" % repr((1, 2)) print "%s" % repr((1, 2)) In order to get some other representation of the tuple, such as without the brackets, you need to convert it into a string. The easiest way to do this is via the join method: (Toggle Plain Text) tup = ("Hello", "World") print ":".join(tup) => Hello:World tup = ("Hello", "World") print ":".join(tup) => Hello:World The only problem with this is that if your tuple contains non-strings, they won't join together. So you first have to convert them, either by a generator comprehension: (Toggle Plain Text) tup = ("Hello", 1) print ", ".join(str(x) for x in tup) => Hello, 1 tup = ("Hello", 1) print ", ".join(str(x) for x in tup) => Hello, 1 Or via map, which applies a function to each element: (Toggle Plain Text) tup = ("Hello", 1) print ", ".join(map(str, tup)) => Hello, 1 tup = ("Hello", 1) print ", ".join(map(str, tup)) => Hello, 1 If you want the representation of the object, use repr instead of str: (Toggle Plain Text) tup = ("Hello", 1) print ", ".join(map(repr, tup)) => "Hello", 1 tup = ("Hello", 1) print ", ".join(map(repr, tup)) => "Hello", 1

Mar 1st, 2007, 6:03 PM	#3
Dietrich Professional Programmer Join Date: Feb 2005 Posts: 434 Rep Power: 4	How about something like this: (Toggle Plain Text) def joker(args): for item in args: print "%s" % item, joker("dad", "dasdsad", "dasdas") def joker(args): for item in args: print "%s" % item, joker("dad", "dasdsad", "dasdas") __________________ I looked it up on the Intergnats!

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Programming Forums > Script Programming > Python

String formatting with tuples