Note: This answer was written for the Python 3.6 alpha releases. A new opcode added to 3.6.0b1 improved f-string performance significantly. The f”…” syntax is effectively converted to a str.join() operation on the literal string parts around the {…} expressions, and the results of the expressions themselves passed through the object.__format__() method (passing any :.. … Read more
The new fstrings in Python interpret brackets in their own way. You can escape brackets you want to see in the output by doubling them: regex = fr'(\d{{1,2}})/(\d{{1,2}})/(\d{{4}}|\d{{2}})’
‘Hey {},’ is contained in your translation dictionary as is. If you use f’Hey {username},’, that creates another string, which won’t be translated. In that case, the format method remains the only one useable, but you could approach the f-string features by using named parameters _(‘Hey {username},’).format(username=username) or if you have a dictionary containing your … Read more
I think you have an old version of python. try upgrading to the latest version of python. F-string literals have been added to python since python 3.6. you can check more about it here
This is actually a brand-new feature as of Python 3.8. Added an = specifier to f-strings. An f-string such as f'{expr=}’ will expand to the text of the expression, an equal sign, then the representation of the evaluated expression. Essentially, it facilitates the frequent use-case of print-debugging, so, whereas we would normally have to write: … Read more
future-fstrings brings f-strings to Python 2.7 scripts. (And I assume 3.3-3.5 based on the documentation.) Once you pip install it via pip install future-fstrings, you have to place a special line at the top of your code. That line is: # -*- coding: future_fstrings -*- Then you can use formatted string literals (f-strings) within your … Read more
f”…” strings are great when interpolating expression results into a literal, but you don’t have a literal, you have a template string in a separate variable. You can use str.format() to apply values to that template: name=[“deep”,”mahesh”,”nirbhay”] user_input = “certi_{element}” # this string i ask from user for value in name: print(user_input.format(element=value)) String formatting placeholders … Read more
Just add a comma after the unpacked list. a = [1, 2, 3] print(f”Unpacked list: {*a,}”) # Unpacked list: (1, 2, 3) There is a longer explanation to this syntax in this thread.
See PEP 498 Literal String Interpolation: The expressions that are extracted from the string are evaluated in the context where the f-string appeared. This means the expression has full access to local and global variables. Any valid Python expression can be used, including function and method calls. So the expressions are evaluated as if they … Read more
From “Formatted string literals” in the Python reference: f-strings are invoke the “format protocol”, same as the format built-in function. It means that the __format__ magic method is called instead of __str__. class Foo: def __repr__(self): return “Foo()” def __str__(self): return “A wild Foo” def __format__(self, format_spec): if not format_spec: return “A formatted Foo” return … Read more