How do I use Python to easily expand variables to strings?

Question

What\'s a nice idiom to do this:

Instead of: print \"%s is a %s %s that %s\" % (name, adjective, noun, verb)

I want to be able to do something to th

Answer 1

use string.Template

>>> from string import Template
>>> t = Template("$name is a $adjective $noun that $verb")
>>> t.substitute(name="Lionel", adjective="awesome", noun="dude", verb="snores")
'Lionel is a awesome dude that snores'

Answer 2

Since Python 3.6 you can now use this syntax, called f-strings, which is very similar to your suggestion 9 years ago

Answer 3

For python 2 do:

print name,'is a',adjective,noun,'that',verb

For python 3 add parens:

print(name,'is a',adjective,noun,'that',verb)

If you need to save it to a string, you'll have to concatenate with the + operator and you'll have to insert spaces. print inserts a space at all the , unless there is a trailing comma at the end of the parameters, in which case it forgoes the newline.

To save to string var:

result = name+' is a '+adjective+' '+noun+' that '+verb

Answer 4

"{name} is a {adjective} {noun} that {verb}".format(**locals())

• locals() gives a reference to the current namespace (as a dictionary).
• **locals() unpacks that dictionary into keyword arguments (f(**{'a': 0, 'b': 1}) is f(a=0, b=1)).
• .format() is "the new string formatting", which can by the way do a lot more (e.g. {0.name} for the name attribute of the first positional argument).

Alternatively, string.template (again, with locals if you want to avoid a redundant {'name': name, ...} dict literal).