Question

我是一个非常新的Python用户（2.7）并且一直在学习Python的艰难之路课程，直到第37章，并决定阅读其他一些学习材料并再次阅读基础知识并进行练习那里。我一直在读这篇文章：

http://anh.cs.luc.edu/python/hands-on/3.1/handsonHtml/ifstatements.html

我刚刚这样做了：

3.1.4.1。研究生锻炼写一个程序，Graduate.py，提示学生他们有多少学分。打印他们是否有足够的学分来毕业。（在洛约拉大学芝加哥分校需要120学分。）

这是我的代码：

print "How many credits do you currently have: "
credits = raw_input("> ")
if credits >= 120:
   print "You have graduated!"
else:
   print "Sorry not enough credits"

但不管我输入的是什么号码只是每次给出“抱歉没有足够的积分”作为答案，为什么？我试过移动一些东西并制作它＆gt;而不是＆gt; =但没有任何效果。我确定这是一个非常简单的东西我想念但我无法弄明白。

我已经在LPTHW课程中完成了几个与此类似的声明练习并且从未遇到过问题。

Answer 1

raw_input()返回一个字符串：

>>> credits = raw_input("> ")
> 150
>>> type(credits)
<type 'str'>

您需要将其投射到int：

credits = int(raw_input("> "))

Answer 2

在您的代码中，您在if语句中将str类型与int类型进行比较。所以它没有像你所想的那样工作。将credit投射为int

print "How many credits do you currently have: "
credits = raw_input("> ")
credits = int(credits)
if credits >= 120:
   print "You have graduated!"
else:
   print "Sorry not enough credits"

Answer 3

我指的是安德鲁·哈灵顿（Andrew Harrington）博士的同一材料，并且我正在做同一程序，我的程序可能看起来很陈旧，因此，如果有人可以对其进行改进，我将不胜感激

def graduateEligibility(credits):
    if credits >= 120:
        print("Congratulations on successfully completing the course.....see you on graduation day!")
    else:
        print("Sorry! Your credits are below 120, please kindly retake the evaluaton tests")


def main():
    E = float(input("Enter your English marks:"))
    M = float(input("Enter your Mathematics marks:"))
    P = float(input("Enter your Physics marks:"))
    C = float(input("Enter your Chem marks:"))
    Cf = float(input("Enter your Comp.Fundamentals marks:"))
    Fin_Edu = float(input("Enter your finance marks:"))
    Const = float(input("Enter your Constitutional.Stds marks:"))
    R = float(input("Enter your Reasoning marks:"))
    TotalCredits = (E+M+P+C+Cf+Fin_Edu+Const+R)
    YourCredits = graduateEligibility(TotalCredits)
main()

为简单起见，我选了8个科目，每个科目有20个学分。

Answer 4

您需要为此接受整数输入，并且还需要处理非整数输入。

print "How many credits do you currently have: "
try:
    credits = int(raw_input("> "))
    if credits >= 120:
        print "You have graduated!"
    else:
        print "Sorry not enough credits"
except ValueError:
    print "Invalid input"

输出：

> 100
Sorry not enough credits

> 121
You have graduated!

> aaaa
Invalid input

Python if语句无法正常工作

4 个答案: