Python“添加”函数问题：为什么这不起作用？
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Python 'add' function issue: why won't this work?
提问by user2331291
I've just started studying Python, and I'm an absolute newbie.
我刚刚开始学习 Python，我是一个绝对的新手。
I'm starting to learn about functions, and I wrote this simple script:
我开始学习函数，我写了这个简单的脚本：
def add(a,b):
return a + b
print "The first number you want to add?"
a = raw_input("First no: ")
print "What's the second number you want to add?"
b = raw_input("Second no: ")
result = add(a, b)
print "The result is: %r." % result
The script runs OK, but the result won't be a sum. I.e: if I enter 5 for 'a', and 6 for 'b', the result will not be '11', but 56. As in:
脚本运行正常，但结果不会是总和。即：如果我为 'a' 输入 5，为 'b' 输入 6，结果将不是 '11'，而是 56。如：
The first number you want to add?
First no: 5
What's the second number you want to add?
Second no: 6
The result is: '56'.
Any help would be appreciated.
任何帮助，将不胜感激。
采纳答案by Kiro
raw_inputreturns string, you need to convert it to int
raw_input返回字符串，您需要将其转换为 int
def add(a,b):
return a + b
print "The first number you want to add?"
a = int(raw_input("First no: "))
print "What's the second number you want to add?"
b = int(raw_input("Second no: "))
result = add(a, b)
print "The result is: %r." % result
Output:
输出：
The first number you want to add?
First no: 5
What's the second number you want to add?
Second no: 6
The result is: 11.
回答by jamylak
You need to convert the strings to ints to add them, otherwise +will just perform string concatenation since raw_inputreturns rawinput (a string):
您需要将字符串转换为整数以添加它们，否则+将只执行字符串连接，因为raw_input返回原始输入（字符串）：
result = add(int(a), int(b))
回答by Sukrit Kalra
This is because raw_input()returns a string and +operator has been overloaded for strings to perform string concatenation. Try.
这是因为raw_input()返回一个字符串并且+操作符已被重载，以便字符串执行字符串连接。尝试。
def add(a,b):
return int(a) + int(b)
print "The first number you want to add?"
a = raw_input("First no: ")
print "What's the second number you want to add?"
b = raw_input("Second no: ")
result = add(a, b)
print "The result is: %r." % result
The resultant output is as follows.
结果输出如下。
>>>
The first number you want to add?
First no: 5
What's the second number you want to add?
Second no: 6
The result is: 11
Converting the string inputs to int, uses the +operator to add the results instead of concatenating them.
将字符串输入转换为int，使用+运算符来添加结果而不是连接它们。
.
.
回答by Jordan Jambazov
You need to cast aand bto integer.
你需要投a和b到整数。
def add(a, b):
return int(a) + int(b)
