String comparison in MATLAB - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to compare two strings for equality.

MATLAB

result = strcmp(str1, [1]);

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Astr1

Bstr2

Cstring2

Dtext

Attempts:

3 left

💡 Hint

Common Mistakes

Using the same variable twice like strcmp(str1, str1) which always returns true.

Using a variable name that does not exist.

The strcmp function compares two strings and returns true if they are exactly the same. Here, str2 is the second string to compare with str1.

2fill in blank

medium

Complete the code to check if the variable inputStr matches the word 'hello'.

MATLAB

isMatch = strcmp([1], 'hello');

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AinputStr

Btext

Cgreeting

Dword

Attempts:

3 left

💡 Hint

Common Mistakes

Using a string literal instead of the variable.

Mixing up the order of arguments (though strcmp is symmetric).

The strcmp function compares inputStr to the string 'hello'. If they are the same, isMatch will be true.

3fill in blank

hard

Fix the error in the code to correctly compare two strings a and b.

MATLAB

if [1](a, b)
    disp('Strings are equal');
else
    disp('Strings are different');
end

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Astrcmp

Bstrcmps

Cisequal

Dstrcmpi

Attempts:

3 left

💡 Hint

Common Mistakes

Using a non-existent function like strcmps.

Using strcmpi when case sensitivity matters.

The correct function to compare two strings for exact equality in MATLAB is strcmp. The option strcmpi ignores case, isequal works for arrays but is not recommended for strings, and strcmps is not a valid function.

4fill in blank

hard

Fill both blanks to create a dictionary (containers.Map) that maps words to their lengths, but only include words longer than 3 characters.

MATLAB

words = {'apple', 'cat', 'banana', 'dog'};
lengths = containers.Map([1], [2]);

function keys = getKeys(words)
    keys = {};
    for i = 1:length(words)
        if length(words{i}) > 3
            keys{end+1} = words{i};
        end
    end
end

function values = getValues(words)
    values = [];
    for i = 1:length(words)
        if length(words{i}) > 3
            values(end+1) = length(words{i});
        end
    end
end

keys = getKeys(words);
values = getValues(words);

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Akeys

Bwords

Cvalues

Dlengths

Attempts:

3 left

💡 Hint

Common Mistakes

Using the original words list without filtering.

Swapping keys and values in the constructor.

The containers.Map constructor takes two cell arrays: one for keys and one for values. Here, keys holds the filtered words, and values holds their lengths.

5fill in blank

hard

Fill all three blanks to create a logical array that marks which strings in listStr start with the letter 'a' (case insensitive).

MATLAB

listStr = {'apple', 'Banana', 'avocado', 'Cherry'};
startsWithA = arrayfun(@(x) [1](x, '[3]', [2]), listStr);

Drag options to blanks, or click blank then click option'

Astrncmpi

B1

Ca

Dstrcmp

Attempts:

3 left

💡 Hint

Common Mistakes

Using strcmp which compares whole strings.

Using strncmp which is case sensitive.

The function strncmpi compares the first N characters of two strings ignoring case. Here, N is 1, and the character to compare is 'a'.