String searching (contains, strfind) in MATLAB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to check if the string 'hello' contains the substring 'll'.

MATLAB

result = [1]('hello', 'll');

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Aindex

Bstrfind

Cfindstr

Dcontains

Attempts:

3 left

💡 Hint

Common Mistakes

Using strfind returns indices, not a logical value.

The contains function returns true if the substring is found.

2fill in blank

medium

Complete the code to find the starting index of substring 'cat' in the string 'concatenate'.

MATLAB

index = [1]('concatenate', 'cat');

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Acontains

Bstrfind

Cfindstr

Dindex

Attempts:

3 left

💡 Hint

Common Mistakes

Using contains returns logical, not index.

The strfind function returns the starting index of the substring.

3fill in blank

hard

Fix the error in the code to correctly find if 'dog' is in 'hotdog'.

MATLAB

found = [1]('hotdog', 'dog');
if found
    disp('Found!')
end

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Afindstr

Bstrfind

Ccontains

Dindex

Attempts:

3 left

💡 Hint

Common Mistakes

Using strfind returns indices, not a logical value.

contains returns a logical value suitable for if conditions.

4fill in blank

hard

Fill both blanks to create a dictionary of words and their starting indices if the word length is greater than 3.

MATLAB

words = {'apple', 'bat', 'cat', 'doge'};
indices = containers.Map();
for i = 1:length(words)
    word = words{i};
    if length(word) [1] 3
        indices(word) = [2]('concatenate', word);
    end
end

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A>

Bstrfind

C<

Dcontains

Attempts:

3 left

💡 Hint

Common Mistakes

Using contains instead of strfind for index.

Use > to check length and strfind to find the index.

5fill in blank

hard

Fill all three blanks to create a map of uppercase words and their indices if the word contains 'at'.

MATLAB

words = {'cat', 'dog', 'bat', 'rat'};
indices = containers.Map();
for i = 1:length(words)
    word = words{i};
    if [1](word, 'at')
        indices([2]) = [3]('concatenate', word);
    end
end

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Acontains

Bword

Cstrfind

Dupper(word)

Attempts:

3 left

💡 Hint

Common Mistakes

Using word instead of upper(word) as key.

Use contains to check substring, upper(word) as key, and strfind for index.