How to Handle \'Too Many Values to Unpack\' Error When Iterating Over Dictionaries?

Unpacking Multiple Values: Resolving 'Too Many Values to Unpack' with Dictionaries

The 'too many values to unpack' error typically occurs when attempting to unpack more values than available in a given sequence. When iterating over a dictionary, specifically with a key-value pair format, a similar error can arise.

Consider the following code snippet:

<code class="python">first_names = ['foo', 'bar']
last_names = ['gravy', 'snowman']

fields = {
    'first_names': first_names,
    'last_name': last_names,
}

# error occurs on this line
for field, possible_values in fields:
    print(field, possible_values)</code>

When executing this code, Python will encounter the error, as it attempts to unpack two values (key and value) from the dictionary's key-value pair. To resolve this issue, the correct syntax should be utilized depending on the Python version:

Python 3

In Python 3, the items() method should be employed to iterate over the dictionary's items, which returns a list of tuples containing key-value pairs.

<code class="python">for field, possible_values in fields.items():
    print(field, possible_values)</code>

Python 2

For Python 2, the iteritems() method should be used instead, as items() does not exist in this version.

<code class="python">for field, possible_values in fields.iteritems():
    print(field, possible_values)</code>

By using the appropriate method, the code will iterate through the dictionary's key-value pairs successfully, printing the field and corresponding possible values.

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