使用 f 字符串格式化字符串

Question

I just want to do something for transformation my string into view like: (2 ** 5)(5)(7 ** 2)(11), but my code works wrong. tell me please, where are my mistakes?!

values = [(2, 5), (5, 1), (7, 2), (11, 1)]
result = str(f'({i[0]}**{i[1]})' for i in values if i[1] != 1 else f'({i[0]})')
print(result) # (2 ** 5)(5)(7 ** 2)(11)

Answer 1

this is a variant:

values = [(2, 5), (5, 1), (7, 2), (11, 1)]
result =  ''.join(f'({base} ** {exp})' if exp != 1 else f'({base})' 
                  for base, exp in values)
print(result) # (2 **  5)(5)(7 ** 2)(11)

where i use tuple unpacking to assign base and exp to the items of your list and then str.join (in the form ''.join(...) ) to join the individual terms.

so in the first iteration you get base=2, exp=5 which will be converted to the string '(2 ** 5)' ; on the second iteration you get base=5, exp=1 which will be converted to the string '(5)' (and so on); then these strings will be joined with '' (ie an empty string) in between.

Answer 2

Place your ternary operator before the list comprehension part:

result = "".join([
    f'({i[0]} ** {i[1]})' if i[1] != 1 else f'({i[0]})'
    for i in values 
])
print(result) # (2 ** 5)(5)(7 ** 2)(11)```

Answer 3

that is my decision. thank to all!

result =  ''.join('({} ** {})'.format(i[0], i[1]) if i[1] != 1 else '({})'.format(i[0]) for i in values)