algorithm-python2/divide.py at master · yangjun616/algorithm-python2 · GitHub

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#! /usr/bin/env python

#coding:utf-8

def divide(numerator, denominator, detect_repetition=True, digit_limit=None):

# 如果是无限小数，必须输入限制的返回小数位数:digit_limit

# digit_limit = 5，表示小数位数5位，注意这里的小数位数是截取，不是四舍五入.

if not detect_repetition and digit_limit == None:

return None

decimal_found = False

v = numerator // denominator

numerator = 10 * (numerator - v * denominator)

answer = str(v)

if numerator == 0:

return answer

answer += '.'

# Maintain a list of all the intermediate numerators

# and the length of the output at the point where that

# numerator was encountered. If you encounter the same

# numerator again, then the decimal repeats itself from

# the last index that numerator was encountered at.

states = {}

while numerator > 0 and (digit_limit == None or digit_limit > 0):

if detect_repetition:

prev_state = states.get(numerator, None)

if prev_state != None:

start_repeat_index = prev_state

non_repeating = answer[:start_repeat_index]

repeating = answer[start_repeat_index:]

return non_repeating + '[' + repeating + ']'

states[numerator] = len(answer)

v = numerator // denominator

answer += str(v)

numerator -= v * denominator

numerator *= 10

if digit_limit != None:

digit_limit -= 1

if numerator > 0:

return answer + '...'

return answer

if __name__=="__main__":

print "5divide2",

print divide(5,2)

print "10divide3",

print divide(10,3)

print divide(10,3,5)

print "15divide7"

print divide(15,7)

print divide(15,7,True,3)

algorithm-python2/divide.py at master · yangjun616/algorithm-python2 · GitHub

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