string % dictionary question

[Sam Sungshik Kong]

Hello, group!

di={}
di["test"]=None
s="%(test)s" % di
s

'None'
</code>

I want the result to be just empty string when the dictionary value is None.
Is there a good way?

TIA.
Sam

 

[Jorge Godoy]

Hello, group!

di={}
di["test"]=None
s="%(test)s" % di
s

'None'
</code>

I want the result to be just empty string when the dictionary value is None.
Is there a good way?

You can check it after the definition and make the necessary changes...

di={}
di["test"]=None
s="%(test)s" % di
if s == "None": s = "" ....
s ''
di["test"] = 1
s = "%(test)s" % di
if s == "None": s = "" ....
s '1'

Be seeing you,

 

[Sam Sungshik Kong]

Thanks for the reply.

What if the string is more complicated?
For example,

di = {}
di["name"] = "Sam"
di["age"] = None
s = "name: %(name)s, age: %(age)d" % di

Thanks.

Sam

Hello, group!

di={}
di["test"]=None
s="%(test)s" % di
s

'None'
</code>

I want the result to be just empty string when the dictionary value is None.
Is there a good way?

You can check it after the definition and make the necessary changes...

di={}
di["test"]=None
s="%(test)s" % di
if s == "None": s = "" ...
s ''
di["test"] = 1
s = "%(test)s" % di
if s == "None": s = "" ...
s '1'

Be seeing you,

 

[Bryan]

Thanks for the reply.

What if the string is more complicated?
For example,

di = {}
di["name"] = "Sam"
di["age"] = None
s = "name: %(name)s, age: %(age)d" % di

Thanks.

Sam

instead of setting di['age'] to None, set it to empty string. if you are setting di['age'] with a variable then you can
insure that you use an empty string for None by doing something like this:


di['age'] = somevar or ''



bryan

 

[Erik Max Francis]

I want the result to be just empty string when the dictionary value is
None.
Is there a good way?

Best way is either subclass dict or write a simple wrapper object which
returns "" instead of None. Or use EmPy .

 

[Alex Martelli]

Hello, group!

di={}
di["test"]=None
s="%(test)s" % di
s

'None'
</code>

I want the result to be just empty string when the dictionary value is None.
Is there a good way?

class Translator(object):
def __init__(self, d, t=''):
self.d = d
self.t = t
def __getitem__(self, n):
result = self.d.get(n)
if result is None: result = self.t
return result

s = 'before%(test)safter' % Translator({})

will leave 'beforeafter' in s, as the missing key gets treated just like
a None. If you want this to raise, and only explicit None values to get
translated, change the first line of __getitem__ into
'result=self.d[n]'.


Alex

 

[Larry Bates]

di={}
di["test"]=None
s="%s" % (di["test"] or "")
print "s='%s'" % s

works, but might be better to set values to empty strings
unless you want to test for the existence of None somewhere
else in your program.

Larry Bates

Hello, group!

di={}
di["test"]=None
s="%(test)s" % di
s

'None'
</code>

I want the result to be just empty string when the dictionary value is None.
Is there a good way?

TIA.
Sam

 

[Sam Sungshik Kong]

Thanks Larry!

What about numbers?

s="%d" % di["test"]

di["test"] could be a number or None.

What can I do with that?
"" is not appropriate, right?

Sam

di={}
di["test"]=None
s="%s" % (di["test"] or "")
print "s='%s'" % s

works, but might be better to set values to empty strings
unless you want to test for the existence of None somewhere
else in your program.

Larry Bates

Hello, group!

di={}
di["test"]=None
s="%(test)s" % di
s

'None'
</code>

I want the result to be just empty string when the dictionary value is None.
Is there a good way?

TIA.
Sam