Strings are converted to cells during readtable

I am incrementally saving data to a csv file which includes strings:

data = table("string1", "string2");
writetable(data, "data.csv");

Later on:

data_from_file = readtable('data.csv')

data_from_file =

1×2 table

Var1 Var2

___________ ___________

{'string1'} {'string2'}

Note that the data are now char arrays in cells.

This is causing lots of problems, for example when I try to join the old data with the new:

new_data = table("string1", "string2");
data = outerjoin(data_from_file, new_data, 'MergeKeys', true)

Error using tabular/outerjoin (line 152)

Left and right key variables 'Var1' and 'Var1' are not comparable because one is

a non-cell.

Is there a way to avoid this problem or convert the chars back to strings after readtable?

[KSSV]

Show us your new_data.

[Bill Tubbs]

E.g.

new_data = table("string1", "string2");

Answer 1

[Stephen23]

The simple solution is to specify the TEXTTYPE option when importing:

data = table("string1", "string2");
writetable(data, "data.csv");
data_from_file = readtable('data.csv', 'TextType','string')

data_from_file = 1×2 table
      Var1         Var2   
    _________    _________

    "string1"    "string2"

[Bill Tubbs]

Great. Thanks.

Answer 2

[KSSV]

You can convert cell into a string and then use join.

data = table("string1", "string2");
writetable(data, "data.csv");


data_from_file = readtable('data.csv') ;
for i = 1:width(data_from_file)
    data_from_file.(i) = string(data_from_file.(i)) ;
end

new_data = table("string3", "string4");
data = outerjoin(data_from_file, new_data, 'MergeKeys', true)