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aasmpro/convert_to_int.py

Last active March 24, 2022 22:02
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Python script to convert string to int without using built-in functions, and return the value with 3 fixed decimal places
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convert_to_int.py
import re
digits_dict = {'0': 0, '1': 1, '2': 2, '3': 3, '4': 4, '5': 5, '6': 6, '7': 7, '8': 8, '9': 9}
regex = "\s*(\+|\-)?\s*((\d)*(\.)?(\d)*)"
value = input()
result = re.search(regex, value)
sign = result.group(1) == '-' and -1 or 1
digits = result.group(2)
integer_value = 0
fraction_value = 0
decimal = False
fraction_counter = 1
for digit in digits:
if digit == '.':
decimal = True
continue
if decimal:
fraction_value = (fraction_value * 10) + digits_dict[digit]
fraction_counter *= 10
else:
integer_value = integer_value * 10 + digits_dict[digit]
if decimal:
integer_value = integer_value + ( fraction_value / fraction_counter )
print("{:.3f}".format(integer_value * sign))
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