What I want to do is:
property = "name"
formatter = "my %s is %s" % property
print formatter % "wong2" // "my name is wong2"
but the first line gives "not enough arguments for format string" error.
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5 Answers
>>> property = "name"
>>> formatter = "my %s is %%s" % property
>>> print formatter % "wong2"
my name is wong2
Comments
A double-percent will create a single-percent sign after formatting:
formatter = "my %s is %%s"
Comments
You can escape a formatter by doubling it
formatter = "my %s is %%s" % property
You can also do all substitutions at the same time using by-name instead of positional formatting:
formatter = "my %(property)s is %(name)s"
print formatter % { "property": "name",
"name": "wong2" }
This forms allows for a variable number of substitutions (i.e. not all keys in the dictionary needs to be used and they may be used more than once). This is important if for example the format string is read from a configuration file.
Comments
Here's a fun way to do it with a helper class
>>> property = "name"
>>> class D(dict):
... def __missing__(self, key):
... return "%("+key+")s"
...
>>> formatter = "my %(property)s is %(value)s"%D(property=property)
>>> formatter%D(value="wong2")
'my name is wong2'
Comments
I personally don't like the % formatting syntax, so I'll suggest quite the same as previous answers but using the format syntax:
property = 'name'
formatter = "my {} is {{}}".format(property) #=> "my name is {}"
print formatter.format('wong')
