Each number on telephone keypads, except 0 and 1, corresponds to a set of uppercase letters as shown in this list: 2 ABC, 3 DEF, 4 GHI, 5 JKL, 6 MNO, 7 PQRS, 8 TUV, 9 WXYZ Hence, a phone-number specification can include uppercase letters and digits.

I can not quite figure out why my code does not perform. I keep getting syntax errors that dont make sense to me. Such as "parse errors"

[Emma Sellers]

I realized I would need to change the up on line 11 to boolean

[Star Strider]

Please copy and paste your code from your Editor window to a Comment here.

Pictures of code are like pictures of food — enticing but not nourishing.

[Emma Sellers]

function [telephone] = dial(up)
characters = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ';
numbers = '012345678922233344455566677778889999';
[boolean,coords] = ismember(up,characters);
telephone = sscanf(numbers(coords), '%lu'); 
for i = 1 : sizeof(up) 
    if  boolean(i) = 0 
        telephone = [];
    end
end 
end

Answer 1

[Neil Sheridan]

Firstly sizeof isn't a function (on my MATLAB setup) so I changed to size. Also, use == to check equality of numbers.

for i = 1 : size(up)

if boolean(i) == 0

telephone = [];

end

end

[Emma Sellers]

Feedback: Your function performed correctly for argument(s) '1FUNDOG4YOU'

Feedback: Your function performed correctly for argument(s) '12AQZ2'

Feedback: Your function performed correctly for argument(s) '1234567890'

Feedback: Your function performed correctly for argument(s) 'ABCDEFGHIJKLMNOP'

Feedback: Your function performed correctly for argument(s) 'QRSTUVWXYZ'

Feedback: Your program made an error for argument(s) '[phone]'

Your solution is _not_ correct.

[Emma Sellers]

For some reason I am still getting an error on the one that does not contain valid inputs.

[Steven Lord]

What does your homework assignment state should happen if the input contains parentheses [(, )] or dashes [-]?

Should they be ignored, should your function return some sort of "sentinel" value (NaN or [], for example) indicating something unexpected / unsupported happened, or should they cause your function to throw an error?

[Emma Sellers]

The function should return 0.

this is my current code:

function [telephone] = dial(up)

characters = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ';

numbers = '012345678922233344455566677778889999';

[boolean,coords] = ismember(up,characters);

telephone = sscanf(numbers(coords), '%lu');

for i = 1 : size(up)

if boolean(i) == 0

telephone = 0;

end

end

end

[Emma Sellers]

It should work if I could do an If Else statement, but for some reason everytime I put in an If Else statement I get a bunch of syntax errors.. Maybe a while loop?

[Emma Sellers]

something like this?

function [telephone] = dial(up)


characters = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ';
numbers = '012345678922233344455566677778889999';
[boolean,coords] = ismember(up,characters);

while boolean ~= 0 
telephone = sscanf(numbers(coords), '%lu'); 
end 

    while boolean == 0 
        telephone = 0 ; 
    end 
    
end

[Neil Sheridan]

Try this one:

function [telephone] = dial(up)

characters = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ';

numbers = '012345678922233344455566677778889999';

[boolean,coords] = ismember(up,characters);

if any(boolean==0)

telephone = [];

else

telephone = sscanf(numbers(coords), '%lu');

end

end

[Steven Lord]

No need for a loop to detect an unsupported character.

Consider how you could use the any or all functions to distinguish the two boolean variables created by the code below.

characters = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ';
numbers = '012345678922233344455566677778889999';

% Contains only numbers
up = '8675309'
boolean = ismember(up,characters)

% Contains a non-letter, non-number character
up = '867-5309'
boolean = ismember(up,characters)

[Emma Sellers]

Still doesn't work :/ It makes perfect sense to me

this is even what I get when I run the code on the one it claims there is an error..

 up = '[phone]'

up =

[phone]

>> 
>> dial(up)

ans =

     []

[Emma Sellers]

You can assume that a phone number never starts with 0. If the input contains any illegal characters, the function returns 0. You are not allowed to use the built-in function strrep.

[Emma Sellers]

This answer gives them what they are asking for.. Thats why i'm confused.

function [telephone] = dial(up)
characters = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ';
numbers = '012345678922233344455566677778889999';
[boolean,coords] = ismember(up,characters);
if any(boolean==0)
    telephone = '0';
else
    telephone = sscanf(numbers(coords), '%lu'); 
end
end

[Steven Lord]

This answer gives them what they are asking for.. Thats why i'm confused.

Does it? There's a difference between '0' (a char array with one element) which is what your code returns and 0 (a double array with one element) which is what the text you quoted two comments above states. It sounds like the assignment requires you to specify 0 (the number) not '0' (the character) as a "sentinel" value.

[Emma Sellers]

I've tried: 0, '0', and []

[Emma Sellers]

Figured it out.. All i had to do was put uint64(0).

Answer 2

[Neil Sheridan]

When a character is not found in characters() then coords(i) will be 0. numbers(0) will return an error because there is no zeroth element.

Answer 3

[RAMAKANT SHAKYA]

function s2=dial(n)
p=[n];
s1='';
tx = ismember(p, ['A':'Z','0':'9']);%only digits and capital letters
tx1=sum(tx);
if length(p)<=16&& p(1,1)~='0'&& tx1==length(p) %finding letters
    for c=1:length(p)
        if p(c)=='A' || p(c)=='B' || p(c)=='C'
            s='2';
        elseif p(c)=='D' || p(c)=='E' || p(c)=='F'
            s='3';
        elseif p(c)=='G' || p(c)=='H' || p(c)=='I'
            s='4';
        elseif p(c)=='J' || p(c)=='K' || p(c)=='L'
            s='5';
        elseif p(c)=='M' || p(c)=='N' || p(c)=='O'
            s='6';
        elseif p(c)=='P' || p(c)=='Q' || p(c)=='R' || p(c)=='S'
            s='7';
        elseif p(c)=='T' || p(c)=='U' || p(c)=='V'
            s='8';
        elseif p(c)=='W' || p(c)=='X' || p(c)=='Y' || p(c)=='Z'
            s='9';
        else
            for r=0:9   %finding digit if present
                t=num2str(r);
                if p(c)==t
                    s=t;
                end
            end
        end
        s1=strcat(s1,s);    %adding string
        s2=str2num(s1);     %change into number
           
        s2=uint64(s2);  %changing class
        
    end
else
    s2=uint64(0);
end

end