ExamAdept

How do you check if a key exists in a dictionary without raising an error if the key is not present?

A:

if dictionary.contains(key):

B:

if key.exists_in(dictionary):

C:

if key in dictionary:

D:

if dictionary.has_key(key):

Answer: C

The in keyword is used to check if a key exists in a dictionary.

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How do you create a dictionary with default values for keys?

A:

default_dict = dict.default(value)

B:

default_dict = dict.fromkeys(keys, value)

C:

default_dict = dict.create(keys, value)

D:

default_dict = dict(keys, value)

Answer: B

The fromkeys() method is used to create a dictionary with default values for specified keys.

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What is the purpose of the dictionary.popitem() method?

A:

Removes the last key-value pair from the dictionary.

B:

Removes a random key-value pair from the dictionary.

C:

Raises a KeyError.

D:

Adds a new key-value pair to the dictionary.

Answer: B

The popitem() method removes a random key-value pair from the dictionary.

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How do you check if a key exists in a dictionary and, if not, add a default value to it?

A:

if key not in dictionary: dictionary[key] = default_value

B:

dictionary.check_and_add(key, default_value)

C:

dictionary.ensure_key(key, default_value)

D:

dictionary.add_default(key, default_value)

Answer: A

The provided code checks if the key exists in the dictionary, and if not, adds the key with the specified default value.

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What is the result of the expression dictionary.get('key')?

A:

Returns the value for 'key' if present, otherwise returns None.

B:

Raises a KeyError if 'key' is not present.

C:

Returns True if 'key' is present, False otherwise.

D:

Returns a tuple containing 'key' and its value.

Answer: A

The get() method returns the value for 'key' if present, otherwise returns None.

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Questions for: Dictionaries