possible_ms1 = [i*.1 for i in range(-100, 101, 1)] #your list comprehension here
print(possible_ms1)
possible_ms2 = [i/10 for i in range(-100, 101, 1)] #your list comprehension here
print(possible_ms2)

Multiply by .1 gives dirty results.
Divide by 10 gives clean results.

Not a bug. 0.1 is a binary floating point value, please read the FAQs:

https://docs.python.org/3/faq/design.html#why-are-floating-point-calculations-so-inaccurate

1/10 = 0.1 in decimal cannot be represented *exactly* in binary floating point, so when you type 0.1 as a float, the actual value you get is the closest number you can get using 53 bits for the significant digits, 8 bits for the exponent and 1 bit for the sign (plus or minus). That is approximately 0.1000000000000000056 or so.

Unfortunately you cannot get any closer to 1/10 in binary floating point numbers, for the same reason you cannot get 1/3 exactly in decimal.

See also 

https://stackoverflow.com/questions/8215437/floating-point-accuracy-in-python

https://stackoverflow.com/questions/21895756/why-are-floating-point-numbers-inaccurate

https://stackoverflow.com/questions/1089018/why-cant-decimal-numbers-be-represented-exactly-in-binary?noredirect=1&lq=1

nosy: + steven.daprano
messages: + msg332975

resolution: not a bug
stage: resolved