Python:浮点输入作为整数输出返回？

Question

我希望你们都度过了充实的一天。我正在学习 python，我写了这个小欧姆定律计算器作为学习练习。该程序运行良好，但即使我将用户输入转换为“ float ”，函数也只返回整数答案。 (例如，如果我选择电压并输入 0.7 安培，它会返回一个不正确的整数)这是我的代码:

# ohm's law calculator

# These functions perform the calculations, but the result currently only prints as an integer.
def voltage(i, r):
    return i * r



def current(r, v):
    return r / v


def resistance(i, v):
    return i / v




# First user interface menu    

print "What value would you like to solve for?"

print "1. Voltage"
print "2. Current"
print "3. Resistance"

choice = raw_input(">>> ")



#These are calling the functions.

#This gives values to "i" and "r" from user input as floating point numbers the print line calls the "voltage" function and prints out the results of its calculation using "%d"
if choice == "1":
    i=float(raw_input("Enter current:"))
    r=float(raw_input("Enter resistance:"))
    print "%d volts" % voltage(i, r)


elif choice == "2":
    r=float(raw_input("Enter resistance:"))
    v=float(raw_input("Enter voltage:"))
    print "%d amps" % current(r, v)



elif choice == "3":  
    i=float(raw_input("Enter current:"))
    v=float(raw_input("Enter voltage:"))
    print "%d ohms" % resistance(i, v)

#This line is here partly because its funny, and partly because I thought it would be cool to create my own error message   
else:
print "Invalid number. Your system will crash momentarily."   

如果有任何使此代码更简洁的提示，我也将不胜感激。我。 e.更具可读性或工作效率更高。谢谢。

Answer 1

不要使用 %d 输出 float ，使用 %f。

最好还是使用新的 format 函数，让 Python 选择最佳表示:

print "{0} volts".format(voltage(i, r))