How to rearrange categoricals to a specified sequence

Question

Xaiver Sim 2019-11-8

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/489934-how-to-rearrange-categoricals-to-a-specified-sequence

回答： Campion Loong 2019-11-15

Hi all,

I am a Earth and Environmental Science student trying to do his group project and failing miserably.

I am trying to plot the frequency of the number of storms per month for a year.

I used tabulate to get the total number of storms oer month and then plot them using bar.

However, the months that are tabulated are in a disorganised arrangement and i would like to plot them following the correct monthly order.

I have tried listing them out as per the matlab instructions however, it keeps returning me that it is not a permutation of the categorical.

the categorical gives me a 12x1 categorical and the names of the months are spelled correctly

I have also tried using the function perms to calculate all possible permutations of the 12 months, however , matlab does not let me as it is too big of an output (42.8GB)

Pls send help :)

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Campion Loong 2019-11-15

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/489934-how-to-rearrange-categoricals-to-a-specified-sequence#answer_401737

在 MATLAB Online 中打开

The categories of your categorical array is sorted in alphabetical order.

% 'c' is your categorical array
>> categories(c)
ans =
  12×1 cell array
    {'April'    }
    {'August'   }
    {'December' }
    {'February' }
    {'January'  }
    {'July'     }
    {'June'     }
    {'March'    }
    {'May'      }
    {'November' }
    {'October'  }
    {'September'}

Note that order of the categories is independent of the order of elements in the array itself:

>> c
ans = 
  12×1 categorical array
     January 
     February 
     March 
     April 
     May 
     June 
     July 
     August 
     September 
     October 
     November 
     December

In this state, when you call bar with the categorical array and a numeric vector (i.e. your monthly rainfall), the visualization looks out of order:

% A naive example of 1:12
>> bar(c, 1:12)

To get the bars in desired order, reorder the categorical array's categories before calling bar:

>> months_in_order = ["January" "February" "March" "April" "May" "June" "July" "August" "September" "October" "November" "December"];
>> c = reordercats(c, months_in_order);
>> bar(c, 1:12);