How can I print literal curly-brace characters in a 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

User · Answer

I recently ran into this  because I wanted to inject strings into preformatted JSON  My solution was to create a helper method  like this   def preformat msg           allow   key   to be used for formatting in text     that already uses curly braces   First switch this into     something else  replace curlies with double curlies  and then     switch back to regular braces             msg   msg replace         lt  lt  lt    replace         gt  gt  gt        msg   msg replace            replace                msg   msg replace   lt  lt  lt         replace   gt  gt  gt             return msg   You can then do something like   formatted   preformat                    foo      bar              format bar  gas     Gets the job done if performance is not an issue

User · Answer

You can do this by using raw string method by simply adding character  r  without quotes before the string     to print   I am inside braces   print r  I am inside braces

User · Answer

You can use a  quot quote wall quot  to separate the formatted string part from the regular string part  From  print f quot  Hello   42  quot    to print  quot  Hello  quot f quot   42  quot     A clearer example would be string   10 print f quot  string   word  quot    Output  NameError  name  word  is not defined  Now  add the quote wall like so  string   10 print f quot  string  quot  quot   word  quot    Output  10  word

User · Answer

You need to double the    and       gt  gt  gt  x        Hello     0     gt  gt  gt  print x format 42       Hello   42     Here s the relevant part of the Python documentation for format string syntax      Format strings contain    replacement fields    surrounded by curly braces     Anything that is not contained in braces is considered literal text  which is copied unchanged to the output  If you need to include a brace character in the literal text  it can be escaped by doubling     and

User · Answer

If you need to keep two curly braces in the string  you need 5 curly braces on each side of the variable    gt  gt  gt  myvar    test   gt  gt  gt        0       format myvar     test

User · Answer

If you are going to be doing this a lot  it might be good to define a utility function that will let you use arbitrary brace substitutes instead  like  def custom format string  brackets   args    kwargs       if len brackets     2          raise ValueError  Expected two brackets  Got      format len brackets        padded   string replace            replace                substituted   padded replace brackets 0        replace brackets 1            formatted   substituted format  args    kwargs      return formatted   gt  gt  gt  custom format     cmd   process 1    brackets       cmd  firefox exe      firefox exe  process 1     Note that this will work either with brackets being a string of length 2 or an iterable of two strings  for multi-character delimiters

User · Answer

When you re just trying to interpolate code strings I d suggest using jinja2 which is a full-featured template engine for Python  ie   from jinja2 import Template  foo   Template      include  lt stdio h gt   void main         printf  hello universe number   number              for i in range 2       print foo render number i     So you won t be enforced to duplicate curly braces as the whole bunch of other answers suggest

User · Answer

If you want to only print one curly brace  for example    you can use     and you can add more braces later in the string if you want   For example    gt  gt  gt  f    there is a curly brace on the left  Oh  and 1   1 is  1   1      there is a curly brace on the left  Oh  and 1   1 is 2

User · Answer

Try this   x       Hello     0

User · Answer

I stumbled upon this problem when trying to print text  which I can copy paste into a Latex document  I extend on this answer and make use of named replacement fields   Lets say you want to print out a product of mulitple variables with indices such as   which in Latex would be  A   0042   A   3141   A   2718   A   0042    The following code does the job with named fields so that for many indices it stays readable   idx mapping     i1  42   i2  3141   i3  2178   print   A     i1 04d       A     i2 04d       A     i3 04d       A     i1 04d       format   idx mapping

User · Answer

Python 3 6   2017   In the recent versions of Python one would use f-strings  see also PEP498    With f-strings one should use double    or     n   42   print f    Hello    n       produces the desired    Hello  42   If you need to resolve an expression in the brackets instead of using literal text you ll need three sets of brackets   hello    HELLO  print f    hello lower          produces   hello

User · Answer

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

User · Answer

Although not any better  just for the reference  you can also do this    gt  gt  gt  x      Hello        gt  gt  gt  print x format         42   Hello  42   It can be useful for example when someone wants to print  argument   It is maybe more readable than          format  argument    Note that you omit argument positions  e g     instead of  0   after Python 2 7

User · Answer

You escape it by doubling the braces   Eg   x       Hello     0   print x format 42

User · Answer

Try doing this   x        Hello     0    print x format 42

User · Answer

Reason is      is the syntax of  format   so in your case  format   doesn t recognize  Hello  so it threw an error   you can override it by using double curly braces          x        Hello     0      or   try  s for text formatting   x       Hello    s  print x  42

User · Answer

If you need curly braces within a f-string template that can be formatted  you need to output a string containing two curly braces within a set of curly braces for the f-string  css template   f quot   tag          margin  0  padding  0        quot  for p   css template format tag  quot p quot      p   margin  0  padding  0

User · Answer

I am ridiculously late to this party   I am having success placing the brackets in the replacement element  like this  print   0   1   format   hello      world      which prints  hello   world   Strictly speaking this is not what OP is asking  as s he wants the braces in the format string  but this may help someone

User · Answer

Use escape sequences to escape the curly braces in the f-string  Ex print f  a  1

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

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