[ Python 常見問題 ] range() for floats

Source From Here 
Question 
Is there a range() equivalent for floats in Python? 

>>> range(0.5, 5, 1.5) 
[0.5, 2, 3.5, ...]

How-To 
Writing one like this shouldn't be too complicated: 

view plaincopy to clipboardprint?

1. def frange(x, y, jump):  
2.   while x < y:  
3.     yield x  
4.     x += jump  

For example: 

>>> list(frange(0.5, 5, 1.5)) 
[0.5, 2.0, 3.5]

As the comments mention, this could produce unpredictable results like: 

>>> list(frange(0, 100, 0.1))[-1] 
99.9999999999986

You can use decimal.Decimal as the jump argument. Make sure to initialize it with a string rather than a float: 

>>> list(frange(0, 100, decimal.Decimal('0.1')))[-1] 
Decimal('99.9')

Or even: 

view plaincopy to clipboardprint?

1. import decimal  
2.   
3. def drange(x, y, jump):  
4.   while x < y:  
5.     yield float(x)  
6.     x += decimal.Decimal(jump)  

And then: 

>>> list(drange(0, 100, '0.1'))[-1] 
99.9