change table var type

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LO
LO 2021-2-8
评论： Jeremy Hughes 2021-2-8
How can I change the variable type in a table from double to string ?
I found plenty of posts with the same issue but during import from excel. My table is already there and I need to change the var type of a column.
  2 个评论
KSSV
KSSV 2021-2-8
Read about num2str, sprintf.
LO
LO 2021-2-8
I resolved by creating a new 1column table of the right type and then concatenating it to the existing table (ugly but it works)

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采纳的回答

Steven Lord
Steven Lord 2021-2-8
Ran in:
A = array2table(magic(4))
A = 4x4 table
Var1 Var2 Var3 Var4 ____ ____ ____ ____ 16 2 3 13 5 11 10 8 9 7 6 12 4 14 15 1
A.Var1 = string(A.Var1)
A = 4x4 table
Var1 Var2 Var3 Var4 ____ ____ ____ ____ "16" 2 3 13 "5" 11 10 8 "9" 7 6 12 "4" 14 15 1
Though depending what you're trying to do, using discretize or categorical to create a categorical array might be a better option.
load patients
patients = table(LastName,Gender,Age,Height,Weight);
head(patients)
ans = 8x5 table
LastName Gender Age Height Weight ____________ __________ ___ ______ ______ {'Smith' } {'Male' } 38 71 176 {'Johnson' } {'Male' } 43 69 163 {'Williams'} {'Female'} 38 64 131 {'Jones' } {'Female'} 40 67 133 {'Brown' } {'Female'} 49 64 119 {'Davis' } {'Female'} 46 68 142 {'Miller' } {'Female'} 33 64 142 {'Wilson' } {'Male' } 40 68 180
patients.AgeCategory = discretize(patients.Age, 0:10:100, 'categorical');
patients.Gender = categorical(patients.Gender);
head(patients)
ans = 8x6 table
LastName Gender Age Height Weight AgeCategory ____________ ______ ___ ______ ______ ___________ {'Smith' } Male 38 71 176 [30, 40) {'Johnson' } Male 43 69 163 [40, 50) {'Williams'} Female 38 64 131 [30, 40) {'Jones' } Female 40 67 133 [40, 50) {'Brown' } Female 49 64 119 [40, 50) {'Davis' } Female 46 68 142 [40, 50) {'Miller' } Female 33 64 142 [30, 40) {'Wilson' } Male 40 68 180 [40, 50)

更多回答（1 个）

KALYAN ACHARJYA
KALYAN ACHARJYA 2021-2-8
编辑：KALYAN ACHARJYA 2021-2-8
"My table is already there and I need to change the var type of a column."
If the data is numeric, you can use num2str(variable_name) to convert numeric var to string data type.
Lets suppose you have table variable T and want to convert string of the particular column variable "col1", then
num2str(T.col1)
  2 个评论
LO
LO 2021-2-8
编辑：LO 2021-2-8
Thanks Kalyan, I am trying to input strings in a table column in a for loop cycle.
So the inputs are actually strings not numbers. when I try to put the strings into the table variable I just get NaNs (because the column type is double instead of string)
Jeremy Hughes
Jeremy Hughes 2021-2-8
I think you should share your code. Hard to tell what you really need to do.

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