python错误for k,v in d: ValueError: too many values to unpack

John Fouhy john at fouhy.net
Tue May 22 00:50:14 CEST 2007

• Previous message: [Tutor] for k,v in d: ValueError: too many values to unpack
• Next message: [Tutor] MS SQL Connection
• Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]

---

On 22/05/07, John Washakie  wrote:> I have a Dictionary, that is made up of keys which are email> addresses, and values which are a list of firstname, lastnamet,> address, etc...>> If I run the following:>> last = {}[...]> for k,v in last:>         print "Email: %s , has the Last name: %s" % (k,v[0])>> I get the error indicated in the subject:> ValueError: too many values to unpackThe "implicit" iteration that dictionaries support only iterates over keys.i.e. you could have done this:for k in last:    print "Key is %s, value is %s" % (k, last[k])Alternatively, you can use the iteritems() method;for k, v in last.iteritems():    print "Key is %s, value is %s" % (k, v)See http://www.python.org/doc/current/lib/typesmapping.html for details.-- John.简单翻译一下，python只支持对于key的遍历，所以不能使用for k,v这种形式，这个时候会提示ValueError: too many values to unpack，使用粗体的形式代替。