Placeholders in strings

I want palceholders in strings.
Something like this: {{*}}
so basically a '{{*}}' == '{{name}} statement is True.
I also want to collect the value of *
so something like this:

string.replace('Hi *', 'Hello *!')

Repl Link:
(don’t ask why I thought of a lame name for my template engine)


contents = contents.replace('{{*}}', vars['*'])

in python? use an f-string

a = 1+2
print(f" My var: {a} is 3")
1 Like

no I meant the value of * can be anything

So, regex? I’m a bit confused.

in flask? or in normal python strings

so these statements are True:

('Hello *!' == 'Hello World!')
('* + *' == '243 + abc')

oh, well then you shouldn’t have them “equal”. they should be subsets

yes. (but the length of the * can be anything)

normal python

I also want to collect the value of *
so smth like this:

string.replace('Hi *', 'Hello *!')
import re

re.match('Hello .*!', 'Hello World!')
re.match('.* + .*', '243 + abc')

Matches everythin except newline characters

I tried re.match but it didn’t suit what I was doing.
This what I’m actually doing:

contents = contents.replace('{{*}}', vars['*'])

so basically something like Jinja2

import re

match = re.match('Hello (.*)!', 'Hello World!')
if match:
    print(  # Outputs: World

match = re.match('(.*) + (.*)', '243 + abc')
if match:
    print(  # Outputs: 243
    print(  # Outputs: abc

Didn’t you read:

re.match doesn’t help, and I’m not matching anything. I’m just replacing.

Ohh I’m dumb.

import re

# Replace 'World' with 'Python'
result = re.sub('Hello (.*)!', 'Hello Python!', 'Hello World!')
print(result)  # Outputs: Hello Python!

# Replace '243' with '123' and 'abc' with 'xyz'
result = re.sub('(.*) + (.*)', '123 + xyz', '243 + abc')
print(result)  # Outputs: 123 + xyz

how can I use that in this:

contents = contents.replace('{{*}}', variables['*'])

Also I want to replace anything inside {{ and }} with the value of the key that has the name of the value inside {{ and }} that is inside the variables dict.

You know what, scratch that, why not just use Jinja (lol)

from jinja2 import Template

contents = Template(contents).render(vars)

I’m making a template engine :man_facepalming:
If I use Jinja then I basically remake Jinja

LOLOL ok ok

You could always use .format, but ofc that only uses {} and not {{}}

# Replace the placeholders with the values
contents = contents.format(**vars)


so you could instead use

import re

def replace(match):
    key =
    return vars.get(key,

contents = re.sub('{{(.*)}}', replace, contents)


(note I haven’t actually tested that)

wait what is var? I thought it was a dictionary

wait never mind
but still… the variables need to be handed to the render function, not the replace function
so is there a way to do it with only one function?