擅长:python、mysql、java
<p>我想这是你想要的:</p>
<pre><code>def func():
sum = 0
number = raw_input("7digit? ")
for i in range(len(number)):
if i%2 ==0:
sum += int(number[i]) * 3
else:
sum += int(number[i])
GTIN8 = int( round(sum, -1)- sum) % 10
return number+ str(GTIN8)
out = func()
print out
</code></pre>
<p>具体工作如下:</p>
^{pr2}$
<p>一般情况下:</p>
<p>如果要向字符串添加字母:只需使用<code>+</code>字符:</p>
<pre><code>>>> a = "1"
>>> b = "12345"
>>> a + b
'112345'
>>>
</code></pre>
<p>如果要将数字添加到左侧的数字:</p>
<pre><code>>>> b = 12345
>>> c = b*10 + a
>>> c
123451
>>>
</code></pre>
<p>如果要向列表中添加元素:</p>
<pre><code>>>> a = 1
>>> b = [1,2,3]
>>> b.append(a)
>>> b
[1, 2, 3, 1]
>>>
>>>
>>> a = "1"
>>> b = ["1", "2", "3"]
>>> b.append(a)
>>> b
['1', '2', '3', '1']
>>>
</code></pre>