String handling questions

I have 2 questions regarding about strings and I would like to get help. 1. How to handle the " ' " in Matlab? - The syntax set_param function is set_param('Model_Name/Block_Name', 'Value', 'data') and I would like to set multiple Block_Name's Value (Block_Name is named as K(i), where i = 1 to N - I tried set_param('Model_Name/K(' & num2str(i) & ')', 'Value', 'data') and set_param('Model_Name/K(' num2str(i) ')', 'Value', 'data') but both failed

2. I have a list of string like [1.21321421412421512312312521131232] and try to convert in to number using num2str() can only convert certain digit, I tried with format long and format longeng but they still cannot handle all of the digits. Is there anyway to handle this?

Answer 1

[Paulo Silva]

set_param(['Model_Name/K(' num2str(i) ')'], 'Value', 'data')

[Raymond Le]

Thank you very much for helping me out. If I have an array

a = [1 23 42 45 42 54 56 43 45] and I would like to set in to an attribute of a block let set Value which only take single value

I tried:

set_param(['Model_Name/K(' num2str(i) ')'], 'Value', a(i+1))

set_param(['Model_Name/K(' num2str(i) ')'], 'Value', 'a(i+1)')

set_param(['Model_Name/K(' num2str(i) ')'], 'Value', ['a(i+1)'])

but I only get for Value of K(0) = a( , instead of Value of K(0) = 1. Then the program errors out.

[Walter Roberson]

set_param(['Model_Name/K(' num2str(i) ')'], 'Value', num2str(a(i+1)) )

Or you might find you prefer the style

set_param( sprintf('Model_Name/K(%d)', i), 'Value', sprintf('%d', a(i+1)) )

Answer 2

[Walter Roberson]

The closest you can get to

1.21321421412421512312312521131232

in MATLAB is

1.21321421412421504015810569399036467075347900390625

which is accurate to within

0.0000000000000002220446049250313080847263336181640625

In order to represent 1.21321421412421512312312521131232 more accurately, you need to use the Symbolic Toolbox,

digits(35);
A = sym('1.21321421412421512312312521131232');

However, to use the number meaningfully you would pretty much need to convert the rest of your numbers to symbolic as well as otherwise intermediate calculations might not retain enough accuracy.

[Raymond Le]

Thank you very much.