ValueError: 不支持的格式字符 'p' (0x70) 在索引 7

Question

I am trying to format the string file name by using a loop here is my code

for i in range(1, 16):
    bgImageFile = ("bg_%01.png" %i)

Answer 1

The syntax requires %d (or %s ), not just % :

for i in range(1, 4):
    bgImageFile = 'bg_%s01.png'%i
    print(bgImageFile)

bg_101.png
bg_201.png
bg_301.png

With Python 3.6+, you can use f-strings ( PEP498 ):

for i in range(1, 4):
    bgImageFile = f'bg_{i}01.png'

Some specifiers you should know ( source ):

%s - String (or any object with a string representation, like numbers)

%d - Integers

%f - Floating point numbers

%.<number of digits>f - Floating point with fixed amount of digits to the right of the dot.

%x/%X - Integers in hex representation (lowercase/uppercase)