Hash table applications in Data Structures Theory - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a hash table that stores key-value pairs.

Data Structures Theory

hash_table = [1]()

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Adict

Bset

Clist

Dtuple

Attempts:

3 left

💡 Hint

Common Mistakes

Using list instead of dict, which does not support key-value pairs.

Using set, which stores only unique values without keys.

The dict type in Python is a built-in hash table that stores key-value pairs efficiently.

2fill in blank

medium

Complete the code to check if a key exists in a hash table.

Data Structures Theory

if [1] in hash_table:

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Aitem

Bindex

Ckey

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Checking for a value instead of a key.

Using an index which is not applicable in hash tables.

To check if a key exists in a hash table (dictionary), you use the key itself with the in keyword.

3fill in blank

hard

Fix the error in the code to add a key-value pair to the hash table.

Data Structures Theory

hash_table[[1]] = 'value'

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A'key'

Bkey

Cvalue

Ditem

Attempts:

3 left

💡 Hint

Common Mistakes

Using an unquoted key which causes a NameError.

Using a value as a key.

Keys in a hash table must be immutable and usually strings are used as keys. Here, the key should be a string literal, so it needs quotes.

4fill in blank

hard

Fill both blanks to create a hash table comprehension that maps words to their lengths for words longer than 3 characters.

Data Structures Theory

{word: [1] for word in words if len(word) [2] 3}

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Alen(word)

B<

C>

Dword

Attempts:

3 left

💡 Hint

Common Mistakes

Using the word itself instead of its length as the value.

Using the wrong comparison operator in the condition.

The comprehension maps each word to its length using len(word). The condition filters words longer than 3 characters using >.

5fill in blank

hard

Fill all three blanks to create a hash table that stores uppercase keys and their values only if the value is positive.

Data Structures Theory

{ [1]: [2] for [3], [2] in data.items() if [2] > 0 }

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Akey.upper()

Bvalue

Ckey

Ditem

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same variable name for key and value.

Not converting keys to uppercase.

Using incorrect variable names in the loop.

The comprehension uses key.upper() to make keys uppercase, value as the dictionary value, and iterates over key, value pairs from data.items(). The condition filters values greater than zero.