Map phase explained in Hadoop - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to define the map function that processes input key-value pairs.

Hadoop

def map([1], value):
    # process input key and value
    pass

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Arecord

Bkey

Cdata

Dinput

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'input' or 'data' instead of 'key' as the first parameter.

The map function takes a key and a value as input parameters. The first parameter is usually called key.

2fill in blank

medium

Complete the code to emit intermediate key-value pairs from the map function.

Hadoop

def map(key, value):
    words = value.split()
    for word in words:
        [1](word, 1)

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Aemit

Bprint

Creturn

Doutput

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'print' or 'return' instead of 'emit'.

In the map phase, the function emit is used to output intermediate key-value pairs.

3fill in blank

hard

Fix the error in the map function to correctly split the input value into words.

Hadoop

def map(key, value):
    words = value.[1]()
    for word in words:
        emit(word, 1)

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Areplace

Bjoin

Cstrip

Dsplit

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'join' which combines strings instead of splitting.

The split() method breaks a string into a list of words, which is needed here.

4fill in blank

hard

Fill both blanks to create a dictionary comprehension that counts word lengths greater than 3.

Hadoop

lengths = {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 '<' instead of '>' in the condition.

The dictionary comprehension maps each word to its length if the length is greater than 3.

5fill in blank

hard

Fill all three blanks to create a dictionary comprehension filtering words by length and mapping to uppercase keys.

Hadoop

result = { [1]: [2] for word in words if len(word) [3] 4 }

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Aword.upper()

Bword

C>

D<=

Attempts:

3 left

💡 Hint

Common Mistakes

Using '<=' instead of '>' in the condition.

The comprehension creates keys as uppercase words, values as the original words, filtering words longer than 4 characters.