CODEWITHSUNDEEP
pythonstring-interpolationf-string
GGChe
GGChe

Reputation: 302

How to include a dict comprehension in an f-string?

Is there any way to use dict comprehension inside a fstring? THe case is the following:

a = ['a', 'b', 'c', 'd']
list_comprehension = [v for v in a]
my_f_string = f"dict comprehension {v:None for v in a}"

I do not wanna use format interpolation ("{}".format(dict_comprehension)). I want to use the most pythonic way to include that list comprehension inside the fstring to be used for logging data.

Upvotes: 3

Views: 2038

Answers (3)

haccks
haccks

Reputation: 106102

What you are trying to do can be simply done as

dict_comp = {v:None for v in a}
my_f_string = f"dict comprehension {dict_comp}"

Or if you really want to use a dict comprehension inside an f-string then you have to place {v:None for v in a} inside another curly braces with a space before and after {v:None for v in a}.

my_f_string = f"dict comprehension { {v:None for v in a} }"

Upvotes: 1

ruohola
ruohola

Reputation: 24107

Yes, of course there is. You simply need to wrap the comprehension in parenthesis ( ), since two consecutive {s are interpreted as a literal "{" string.

a = ['a', 'b', 'c', 'd']
list_comprehension = [v for v in a]

This works:

my_f_string = f"dict comprehension {({v:None for v in a})}"
print(my_f_string)

Output:

dict comprehension {'a': None, 'b': None, 'c': None, 'd': None}

But, this does not work (Stack Overflow's syntax highlighting also helpfully shows that):

my_f_string = f"dict comprehension {{v:None for v in a}}"
print(my_f_string)

Output:

dict comprehension {v:None for v in a}

Upvotes: 4

U13-Forward
U13-Forward

Reputation: 71610

In this case I prefer dict.fromkeys:

my_f_string = f"dict comprehension {dict.fromkeys(a)}"

Shorter and much more elegant :)

And now:

print(my_f_string)

Output:

dict comprehension {'a': None, 'b': None, 'c': None, 'd': None}

Upvotes: 1

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