實現range()和xrange()

 

請實現range和xrange。

 

我的解答如下：

 

def range(start, stop = 0, step = 1):
	val = []
	# when stop and step are not provided 
	if stop == 0:
		i = 0
		while(i < start):
			val.append(i )
			i += 1
	# when stop is provided , step is 
	elif step > 0 and stop > start:
		while(start < stop):
			val.append(start)
			start += step
	elif step < 0 and stop < start:
		while(start > stop):
			val.append(start)
			start += step																																																									
	return val

print 'test 1 :', range(4)
print  'test 2', range(3,10,2)
print 'test 3', range(-3,-20, -2)
print 'test 4',range(0)
print 'test 4',range(1,11)
print 'test 4',range(0,30,5)
print range(0, -10, -1)
	


# def xrange(start, stop = 0, step = 1):
# 	# val = []
# 	# when stop and step are not provided 
# 	if stop == 0:
# 		i = 0
# 		while(i < start):
# 			# val.append(i )
# 			yield i
# 			i += 1
# 	# when stop is provided , step is 
# 	elif step > 0 and stop > start:
# 		while(start < stop):
# 			yield start
# 			start += step
# 	elif step < 0 and stop < start:
# 		while(start > stop):
# 			yield start
# 			start += step																																																									
	


# print 'test 1-1:', xrange(4)
# print 'test 1-2:', [i for i in xrange(10)]
# print  'test 2:', [i for i in xrange(3,10,2)]
# print 'test 3:', [i for i in xrange(-3,-20, -2)]