Can I use a variable name to make logical comparison?
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month = input('Enter the month: ');
months = [January, February, March, April, May, June, July, August, September, October, November, December];
k = find(months==month)
I have created the above array, months, and assigned each month to the number of days in it. I have asked a user to enter a month(in words). Now i want to compare the month the user entered with any of the months in the months array by using the find function, but it always compares the values withing the various months and not the variable names. Is there a workaround for this?
Thank you
4 comentarios
Image Analyst
el 15 de Nov. de 2021
Variable names can contain letters and numbers. Use whatever letters and numbers make for a descriptive variable name. Single letters are usually not descriptive except for really simple cases like x and y and k for a loop iterator.
You never defined January in your code so it doesn't know what that is. You need to assign it to a string or number
January = 'January'; % Character array.
January = "January"; % String Variable.
January = 1; % Double/number.
You can use numbers instead of strings if you want -- your choice.
Respuestas (3)
Chunru
el 15 de Nov. de 2021
months = ["January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"];
%month = input('Enter the month: ');
month = "May"
k = find(months==month)
5 comentarios
Stephen23
el 15 de Nov. de 2021
Editada: Stephen23
el 15 de Nov. de 2021
@Snr Jhay: using lots of separate variables is entirely the wrong approach if you want to write simple, efficient code.
MATLAB is designed for efficient processing of data in arrays, and that is how you should store your data too.
Rik
el 15 de Nov. de 2021
You could use the string datatype (as Chunru suggested), or use a cellstr (a cell array of char vectors):
%month = input('Enter the month: ','s');
% ^^^^
% don't forget this
month='May';
months = {'January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'};
k = find(ismember(months,month))
3 comentarios
Rik
el 15 de Nov. de 2021
They will not, nor should they. You should separate data from metadata. What do these arrays store? If the store average temperature per day, wouldn't MeanTemp make more sense as a variable name than January?
Image Analyst
el 15 de Nov. de 2021
You don't need find().
Simply use ismember():
%month = input('Enter the month: ','s');
% ^^^^
% don't forget this
month='May';
months = {'January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December'};
[~, index] = ismember(month, months)
7 comentarios
Stephen23
el 19 de Nov. de 2021
"so the truth is I'm learning Matlab using Matlab For Engineers by Chapman"
Over the years I have read several books about "learning MATLAB" and without exception they contained outdated, incorrect or misleading advice, and used terminology inconsistent with the MATLAB documentation.
A much more reliable source is: https://www.mathworks.com/help/matlab/getting-started-with-matlab.html
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