I have a string with some placeholder in it like:
url = "http://www.myserver.com/$abc/$foo_or_bar/$xy"
I cannot use Templates (http://is.gd/AKmGxa), because my placeholder-strings needs to be interpreted by some logic.
I need to iterate over all exisiting placeholders and replace them by a code-generated value.
How can I do this? TIA!
Using re.sub which can accept replacement function as a second argument;
>>> url = "http://www.myserver.com/$abc/$foo_or_bar/$xy"
>>>
>>> def some_logic(match):
... s = match.group() # to get matched string
... return str(len(s) - 1) # put any login you want here
...
>>> import re
>>> re.sub('\$\w+', some_logic, url)
'http://www.myserver.com/3/10/2'
BTW, string.Template also can be used if you pass custom mapping:
>>> class CustomMapping:
... def __getitem__(self, key):
... return str(len(key))
...
>>> import string
>>> url = "http://www.myserver.com/$abc/$foo_or_bar/$xy"
>>> string.Template(url).substitute(CustomMapping())
'http://www.myserver.com/3/10/2'