How can I print literal curly-brace characters in python string and also use .format on it?

Question

x = \" \\{ Hello \\} {0} \"
print(x.format(42))

gives me : Key Error: Hello\\\\

I want to print the output: {Hello} 42

Answer 1

The OP wrote this comment:

I was trying to format a small JSON for some purposes, like this: '{"all": false, "selected": "{}"}'.format(data) to get something like {"all": false, "selected": "1,2"}

It's pretty common that the "escaping braces" issue comes up when dealing with JSON.

I suggest doing this:

import json
data = "1,2"
mydict = {"all": "false", "selected": data}
json.dumps(mydict)

It's cleaner than the alternative, which is:

'{{"all": false, "selected": "{}"}}'.format(data)

Using the json library is definitely preferable when the JSON string gets more complicated than the example.