Converting name of month to number

Question

Adrij Roy 2019-1-28

1
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/441927-converting-name-of-month-to-number

编辑： Adam Danz 2021-5-9

I have a cellmatrix where there are two columns wth name of months. I want to replace the name of months by serial numbers from 1 to 12.

How can I do it in matlab 2016a?I am new to matlab & I tried using strcmp, strrep & even with switch.

Please suggest.

1)

 if strcmp(z1(n,5),month(m,1))
             z1{n,5} = strrep(z1{n,5},'z1{n,5}','m')
             break;
         else z1{n,5} = z1{n,5};
 end

2)

str = z1{n,5};
switch (str)
case ('January')
z1{n,5} = 1;
.
.
.
case ('December')
z1{n,5} = 12;
end

None worked correctly.

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Walter Roberson 2019-1-29

Sarah Crimi: strcmp() can use cell array of character vectors without needing to pull the entries out.

>> strcmp({'hello', 'sam'}, {'goodbye', 'sam'})

ans =

1×2 logical array

0 1

Sarah Crimi 2019-2-1

Oh yes, you are right!

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Answer 1

Walter Roberson 2019-1-28

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/441927-converting-name-of-month-to-number#answer_358381

[tf, idx] = ismember(z1(:,5), {'January', 'February', 'March'})

now tf(nn) is true if z1{nn,5} is matched and idx(nn) is the month number if tf(nn) is true. No loop needed.

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Adrij Roy 2019-1-29

在 MATLAB Online 中打开

Sir this is showing error.

%% Converting Month into numbers from 1 to 12
month = {'January','February','March','April','May','June','July','August','September','October','November','December'}';
[tf,idx] = ismember(z1(:,5),{'January','February','March','April','May','June','July','August','September','October','November','December'});
%for n = 2:length(z1)
      %M = {month(z1(:,5))};
        %end
         %if strcmp(z1(n,5),month(m,1))
             %z1{n,5} = strrep(z1{n,5},'z1{n,5}','m')
             %break;
         %else z1{n,5} = z1{n,5};
         %end
    % C = z1{n,5};
     %ff = find(strcmp(month(:,1),C));
     %z1{n,5} = ff;
     
    
 
 %Jan = strrep(z1(:,5),'January','1');
   Error using cell/ismember (line 34)
Input A of class cell and input B of class cell must be cell arrays of strings, unless one is a
string.
Error in Precip_crop_yield (line 51)
[tf,idx] =
ismember(z1(:,5),{'January','February','March','April','May','June','July','August','September','October','November','December'}); 
>> 

Adrij Roy 2019-1-29

Sir I did with strcmp. The month names had a space at last so characters were not maching earlier.

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Answer 2

Adam Danz 2021-5-9

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/441927-converting-name-of-month-to-number#answer_695680

编辑：Adam Danz 2021-5-9

在 MATLAB Online 中打开

Another way to convert month names to numbers that is quite flexible in ignoring case and accpeting month appreviations. Requires Finance Toolbox

monthNames = {'jan','March','october','Nov'};  % accepts string arrays, too
monthNum = month(monthNames,"mmmm")
monthNum = 1×4
     1     3    10    11

Another option that does not require any toolbox but is not as quite as flexible since appreviated month names require a different format string.

% Full month names, not case senstive
monthNames = {'March','May','june'};
month(datetime(monthNames,'InputFormat','MMMM')) % 4 M's
ans = 1×3
     3     5     6
% Abbreviated month names (3 letters), not case sensitive
monthNamesAbrv = {'Jan','Oct','dec'};
month(datetime(monthNamesAbrv,'InputFormat','MMM')) % 3 M's
ans = 1×3
     1    10    12

A safer version of the example above in cases where abbreviations are longer than 3 letters (ie, "Sept")

monthNamesAbrv = {'sept','oct','June'};
monthNamesAbrvClean = cellfun(@(str){str(1:3)},cellstr(monthNamesAbrv));
month(datetime(monthNamesAbrvClean,'InputFormat','MMM')) % 3 M's
ans = 1×3
     9    10     6

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Walter Roberson 2021-5-9

This appears to use the Finance Toolbox

Adam Danz 2021-5-9

Thanks WR. I often overlook dependencies for some toolbox functions I bump into without ever looking them up. I'll update my answer because I just found another way worth sharing, too.

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