How to divide a column in table to other variables?

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Behrooz Daneshian
Behrooz Daneshian 2023-1-12
编辑： Stephen23 2023-1-13
Hi all
I have a table called "TEMP" reporting daily minimum temprature(TMIN), daily maximum temprature(TMAX), and daily average temprature(TAVG) for a specific location in 2004. I want to devide the 'datatype' column into 3 columns of TMIN, TMAX, and TAVG. I will do it using the following code, but I would see 'NaN' values in the new table. Can anyone help me with this regard?
load ("TEMP1.mat");
unstackedTemp = unstack(TEMP,"value","datatype");

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Stephen23
Stephen23 2023-1-13
编辑：Stephen23 2023-1-13
Ran in:
You need to specify the "GROUPINGVARIABLE" option, otherwise "...unstack treats the remaining variables as grouping variables. Each unique combination of values in the grouping variables identifies a group of rows in S that is unstacked into a single row of U." So while you might think that every three lines of TAVG, TMAX, and TMIN form a "set" of values, take a look at the column/variable "attributes": are they the same for each set? (hint: no)
Solution: specify the grouping variable to specify which data get merged onto one line.
S = load('TEMP1.mat')
S = struct with fields:
TEMP: [891×5 table]
T = S.TEMP
T = 891×5 table
date datatype station attributes value _______________________ ________ _____________________ __________ _____ {'2004-02-28T00:00:00'} {'TAVG'} {'GHCND:USR0000ABAN'} {',,U,' } 47 {'2004-02-28T00:00:00'} {'TMAX'} {'GHCND:USR0000ABAN'} {'H,,U,'} 61 {'2004-02-28T00:00:00'} {'TMIN'} {'GHCND:USR0000ABAN'} {'H,,U,'} 31 {'2004-02-29T00:00:00'} {'TAVG'} {'GHCND:USR0000ABAN'} {',,U,' } 55 {'2004-02-29T00:00:00'} {'TMAX'} {'GHCND:USR0000ABAN'} {'H,,U,'} 66 {'2004-02-29T00:00:00'} {'TMIN'} {'GHCND:USR0000ABAN'} {'H,,U,'} 42 {'2004-03-01T00:00:00'} {'TAVG'} {'GHCND:USR0000ABAN'} {',,U,' } 63 {'2004-03-01T00:00:00'} {'TMAX'} {'GHCND:USR0000ABAN'} {'H,,U,'} 69 {'2004-03-01T00:00:00'} {'TMIN'} {'GHCND:USR0000ABAN'} {'H,,U,'} 57 {'2004-03-02T00:00:00'} {'TAVG'} {'GHCND:USR0000ABAN'} {',,U,' } 56 {'2004-03-02T00:00:00'} {'TMAX'} {'GHCND:USR0000ABAN'} {'H,,U,'} 63 {'2004-03-02T00:00:00'} {'TMIN'} {'GHCND:USR0000ABAN'} {'H,,U,'} 53 {'2004-03-03T00:00:00'} {'TAVG'} {'GHCND:USR0000ABAN'} {',,U,' } 63 {'2004-03-03T00:00:00'} {'TMAX'} {'GHCND:USR0000ABAN'} {'H,,U,'} 74 {'2004-03-03T00:00:00'} {'TMIN'} {'GHCND:USR0000ABAN'} {'H,,U,'} 55 {'2004-03-04T00:00:00'} {'TAVG'} {'GHCND:USR0000ABAN'} {',,U,' } 67
T = unstack(T,"value","datatype", "GroupingVariable","date")
T = 297×4 table
date TAVG TMAX TMIN _______________________ ____ ____ ____ {'2004-02-28T00:00:00'} 47 61 31 {'2004-02-29T00:00:00'} 55 66 42 {'2004-03-01T00:00:00'} 63 69 57 {'2004-03-02T00:00:00'} 56 63 53 {'2004-03-03T00:00:00'} 63 74 55 {'2004-03-04T00:00:00'} 67 77 57 {'2004-03-05T00:00:00'} 67 73 58 {'2004-03-06T00:00:00'} 60 71 50 {'2004-03-07T00:00:00'} 54 69 43 {'2004-03-08T00:00:00'} 48 58 41 {'2004-03-09T00:00:00'} 46 59 37 {'2004-03-10T00:00:00'} 43 57 30 {'2004-03-11T00:00:00'} 51 69 29 {'2004-03-12T00:00:00'} 50 62 40 {'2004-03-13T00:00:00'} 52 65 38 {'2004-03-14T00:00:00'} 58 71 49
As an aside, note that the "date" column/variable should probably be DATETIME, not text. This can be fixed using CONVERTVARS (even better: fix this when importing the data):
T = convertvars(T,'date','datetime')
T = 297×4 table
date TAVG TMAX TMIN ___________ ____ ____ ____ 28-Feb-2004 47 61 31 29-Feb-2004 55 66 42 01-Mar-2004 63 69 57 02-Mar-2004 56 63 53 03-Mar-2004 63 74 55 04-Mar-2004 67 77 57 05-Mar-2004 67 73 58 06-Mar-2004 60 71 50 07-Mar-2004 54 69 43 08-Mar-2004 48 58 41 09-Mar-2004 46 59 37 10-Mar-2004 43 57 30 11-Mar-2004 51 69 29 12-Mar-2004 50 62 40 13-Mar-2004 52 65 38 14-Mar-2004 58 71 49

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