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  1. # your code goes here
  2. operators = ['-', '+', '*', '/']
  3.  
  4. def whitespace(s, pos):
  5. 	while s[pos] in [' ', '\n', '\t', '\r']:
  6. 		pos += 1
  7. 	return pos
  8.  
  9. def num(s, pos):
  10. 	buf = []
  11. 	while pos < len(s) and s[pos].isdigit():
  12. 		buf.append(s[pos])
  13. 		pos += 1
  14. 	return (''.join(buf), pos)
  15.  
  16. def flt(s, pos):
  17. 	n, pos = num(s, pos)
  18. 	if s[pos] == '.':
  19. 		pos += 1
  20. 		n2, pos = num(s, pos)
  21. 		return n + '.' + n2, pos
  22. 	return n, pos
  23.  
  24. def op(s, pos):
  25. 	if s[pos] in operators:
  26. 		pos += 1
  27. 	return pos
  28.  
  29. def parse(string):
  30. 	pos = whitespace(string, 0)
  31. 	num1, pos = flt(string, pos)
  32. 	pos = whitespace(string, pos)
  33. 	pos = op(string, pos)
  34. 	pos = whitespace(string, pos)
  35. 	num2, pos = flt(string, pos)
  36. 	return [num1, num2]
  37.  
  38. print parse("4.7 + 4.1")[1]
  39. print parse("4.7 - 4.2")[1]
  40. print parse("4.7 * 4.3")[1]
Success #stdin #stdout 0s 9024KB
comments (?)
stdin 
Standard input is empty
stdout 
4.1
4.2
4.3
https://ideone.com/HI0r5S
language:
Python (cpython 2.7.16)
created:
8 years ago
visibility:
secret

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