What is the difference between A={1 2} and A = { '1','2'} and how to convert one from other ?

What is the difference between A={1 2} and A = { '1','2'} and how to convert one from other ?

[Stephen23]

In addition to the comments below, it is also worth mentioning that unless you have a particular reason to store scalar numerics in a cell array, using a numeric array would be more efficient and likely make processing your data easier:

A = [1,2]

https://www.mathworks.com/help/matlabmobile/ug/creating-matrices-and-arrays.html

Answer 1

[Epsilon]

Hi Geethanjali,

A = {1 2} represents a 1x2 cell array with two double type numeric values, 1 and 2, while A = {'1', '2'} represents a 1x2 cell array with two char type charachter values '1' and '2'. To convert char to double, use the inbuilt function 'str2double', while the function 'num2str' can be used for the reverse conversion. Since MATLAB represents strings as arrays of characters, the above-mentioned functions have the term 'str'.

%To convert the cell arrays
A = {'1', '2'};
A = cellfun(@str2double, A, 'UniformOutput', false);
disp(A)

    {[1]}    {[2]}

B = {1 2};
B = cellfun(@num2str, B, 'UniformOutput', false);
disp(B)

    {'1'}    {'2'}

%Converting only one element
A='1'

A = '1'

A=str2double(A)

A = 1

B=1

B = 1

B=num2str(B)

B = '1'

[Geethanjali]

Worked. Thanks

[Stephen23]

"Since MATLAB represents strings as arrays of characters..."

or as string arrays:

https://www.mathworks.com/help/matlab/matlab_prog/create-string-arrays.html

https://www.mathworks.com/help/matlab/characters-and-strings.html

[Epsilon]

@Stephen23

Thank you for the clarification.

Answer 2

[John D'Errico]

Think of it like this:

1 is a "number" as stored in MATLAB, as is 2.

X = [1 2]

X = 1×2

1 2

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whos X

  Name      Size            Bytes  Class     Attributes

  X         1x2                16  double              

X is stored in double precision. We can add them, subtract them, etc.

But in character form, they are more like pictures of numbers. Text representations thereof. You cannot add them and get an expected result. You cannot do arithmetic on them, and have it do anything that will make sense.

Y = '1'

Y = '1'

whos Y

  Name      Size            Bytes  Class    Attributes

  Y         1x1                 2  char               

You can convert them to numbers, using as has been shown, str2double. But the two forms are stored completely differently.

In the end, both 1 and '1' are representations of the number we fondly think of as "one". What can matter is how it is stored, and how that representation can then be used. Is either truly the number 1? That is a rather philosophical question, about something that is best described as a mathematical concept used as a measure.