<p>您有一个有效、完整的Python行</p>
<pre><code> ostr = istr + ": Was issued by " + IssuerList[int(istr[1])] + " in 20"
</code></pre>
<p>然后,另一行以一元+开头,这不是应用于字符串的有效语句</p>
<pre><code> + istr[2:4] + ". The card expires on " + istr[4:6] + "/" + istr[6:8]
</code></pre>
<p>有关在多行上继续表达式的选项,请参见<a href="https://stackoverflow.com/questions/53162/how-can-i-do-a-line-break-line-continuation-in-python">How can I do a line continuation in Python</a></p>
<p>在<a href="https://www.python.org/dev/peps/pep-0008/#should-a-line-break-before-or-after-a-binary-operator" rel="nofollow noreferrer">style guide</a>中建议的做法是在运算符之前使用括号和break</p>
<pre><code>def Decode(iList):
IssuerList = ["Dummy","enRoute","JCB","Diner's Club","Visa"
,"Master Card","Union Pay","Petroleum"]
TypeList = ["Debit account", "Credit account"]
for istr in iList:
ostr = (istr + ": Was issued by " + IssuerList[int(istr[1])] + " in 20"
+ istr[2:4] + ". The card expires on " + istr[4:6] + "/" + istr[6:8]
+ ". The card is linked to a " + TypeList[int(istr[8])]
+ " with the account number: " + istr[8:])
WriteFile(ostr)
</code></pre>