为什么我得到错误不能将序列乘以'float'PYTHON类型的非int

Question

I wrote a simple program to calculate tax for some electrical parts, it goes like this:

print "How much does it cost?",    
price = raw_input()    
print "Tax: %s" % (price * 0.25)    
print "Price including tax: %s" % (price * 1.25)    
raw_input ("Press ENTER to exit")

And I keep getting this error:

Traceback (most recent call last):
  File "moms.py", line 3, in <module>
    print "Tax: %s" % (price * 0.25)
TypeError: can't multiply sequence by non-int of type 'float'

Answer 1

您需要先将raw_input()返回的字符串转换为float ：

price = float(raw_input("How much does it cost?")) # no need for extra print 

Answer 2

This means that price is not a number. In fact, it's a string, since that's what raw_input returns. You'll want to parse it using float , or use input instead of raw_input .

Answer 3

基本上你不能将一个字符串乘以浮点数，也许你想要的是

price = float(raw_input())

Answer 4

The price is a string. You need to create a float from the string you have input:

>>> price_str = raw_input()
123.234
>>> print type(price)
<type 'str'>
>>> price = float(price_str)
>>> print type(price)
<type 'float'>
>>> print "Tax: %s" % (price * 0.25)   
Tax: 30.8085
>>>