Add Unique Double Values to a Column in Mulitple Table

Question

Amadi Gabriel Udu 2021-3-23

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/781053-add-unique-double-values-to-a-column-in-mulitple-table

评论： Amadi Gabriel Udu 2021-3-23

采纳的回答： Walter Roberson

在 MATLAB Online 中打开

I have imported multiple tables into my matlab environment.

I have added a new column, 'PatientNumber' to the table

RIght now, they all have 'ones'.

How do I give each of my new column a unique identifier in each table?

For instance, PatientNumber column in Table 1 should have 'ones',

PatientNumber column in Table 2 should have 'twos'

Patient Number column in Table 3 should have '3' in all the rows and so on.

%enter the file names with wildcard * for all
filenames = 'Patient_Details*';
files = [pwd '\Data\' filenames '.csv']
%set up the data store
ds = datastore(files,'TreatAsMissing', 'NA', 'Delimiter',',',...
    'ReadVariableNames', true, 'ReadSize', 'file');
%read all the data from the datastore
dataAll = readall(ds);
nrow = size(dataAll,1);
dataAll.PatientNumber = ones(nrow, 1);
for i = dataAll.PatentNumber
    dataAll.PatientNumber=i.*ones(nrow,1)
    i+1
end

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

Walter Roberson 2021-3-23

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/781053-add-unique-double-values-to-a-column-in-mulitple-table#answer_656198

When you use readall() on a TabularText datastore (which is what is generated for .csv files by default), then all of the data is read into a single table() or timetable() object, with no boundaries between the entries.

You will need to switch from readall() to read(), but also configure the datastore with 'ReadSize', 'file' so that it reads a file at a time. You would then add the appropriate label information and store the content, combining all the content after you have reached the last file.