Importing a Table :: [Variables are been modified by Matlab]

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Hi I have recently started using matlab. I am trying to import a spreadsheet as a table and some of my variables [Colum Names] get modified when I look at them using T.Properties.Variablenames. So I checked the function genvalidnames which is apparently responsible for changing the "non-matlab" variable names to standard matlab variable names. My Column names in the Spreadsheet all start with a character, have only underscores and are not longer than nameslength which i checked is 63. Still I get the modified names. Any idea why this will be happening.
  5 Comments
Tejas Sonavane
Tejas Sonavane on 28 Apr 2016
Hi Guys,
Sorry I am fairly new to Matlab and the image I posted up only means that Matlab dosent have much space to show me the whole string and it is trying to show me that this is an array or characters by mentioning [1x28] . Thank you for all quick answers and prompts and help.

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Accepted Answer

Image Analyst
Image Analyst on 28 Apr 2016
I don't see how it's being changed. Here is my code:
t = readtable('VAT_Experiment_Sheet_Assign_Table_Structure_Units.xlsx')
fieldnames(t)
and here is what I see:
ans =
'DCDC_CurrentLimiting_Warning_BOOL'
'DCDC_CoolantOTP_Warning_BOOL'
'DCDC_Wakeup_Status_BOOL'
'DCDC_UnitEnabled_Status_BOOL'
'DCDC_StartUpInitDone_Status_BOOL'
'DCDC_RemoteShutdown_Status_BOOL'
'DCDC_LatchedFault_Status_BOOL'
'DCDC_InputOk_Status_BOOL'
'DCDC_HVIL_OK_Status_BOOL'
'DCDC_Status_Fault_BOOL'
'DCDC_Thermistor_Fault_BOOL'
'DCDC_ShortCircuit_Fault_BOOL'
'DCDC_OutputUV_Fault_BOOL'
'DCDC_OutputOV_Fault_BOOL'
'DCDC_OutputOC_Fault_BOOL'
'DCDC_OTP_Fault_BOOL'
'DCDC_InputUV_Fault_BOOL'
'DCDC_InputOV_Fault_BOOL'
'DCDC_I2C_FAULT_BOOL'
'DCDC_EEPROM_CRCfault_Fault_BOOL'
'DCDC_CANfault_Fault_BOOL'
'DCDCReversPolarity_Fault_BOOL'
'DCDC_ReversPolarity_Status_BOOL'
'DCDC_Coolant_Temprature_VALUE_DEGC'
'DCDC_Output_CURRENT_VALUE_AMP'
'DCDC_Input_Voltage_VALUE_VOLT'
'DCDC_Output_Voltage_VALUE_VOLT'
'DCDC_Output_voltage_UV_Fault_BOOL'
'DCDC_Output_voltage_OV_Fault_BOOL'
'DCDC_Output_limit_Current_VALUE_AMP'
'DCDCOutput_setpoint_Voltage_VALUE_VOLT'
'DCDCDcDc_Set_index_byte_Mplx'
'DCDC_RemoteEnable_Status_ENUM'
'DCDC_Temperature_coolant_Warning_VALUE_DEGC'
'DCDC_Temperature_Coolant_Fault_BOOL_DEGC'
'Properties'
Unless I'm overlooking something, like a double underline or something, the "DCDC_OutputOC_Fault_BOOL" looks the same in both Excel and MATLAB.
  4 Comments
Steven Lord
Steven Lord on 14 Dec 2020
As of release R2019b variable names in table arrays are allowed to contain spaces. They are no longer required to be valid variable names. [Note that in release R2020b which I am using the name of the option for readtable to preserve the variable names has changed, see the R2020b Release Notes by changing the release filter to see that note.] Cell E1 in scores.xlsx is "Winning Percentage" with a space.
>> t = readtable('c:\temp\scores.xlsx')
Warning: Column headers from the file were modified to make them valid MATLAB identifiers before
creating variable names for the table. The original column headers are saved in the
VariableDescriptions property.
Set 'VariableNamingRule' to 'preserve' to use the original column headers as table variable names.
t =
4×5 table
Team Wins Losses Ties WinningPercentage
____________ ____ ______ ____ _________________
{'Bills' } 10 3 0 0.769230769230769
{'Dolphins'} 8 5 0 0.615384615384615
{'Patriots'} 6 7 0 0.461538461538462
{'Jets' } 0 12 0 0
>> t2 = readtable('c:\temp\scores.xlsx', 'VariableNamingRule', 'preserve')
t2 =
4×5 table
Team Wins Losses Ties Winning percentage
____________ ____ ______ ____ __________________
{'Bills' } 10 3 0 0.769230769230769
{'Dolphins'} 8 5 0 0.615384615384615
{'Patriots'} 6 7 0 0.461538461538462
{'Jets' } 0 12 0 0
>> t2{2, "Winning percentage"}
ans =
0.615384615384615

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More Answers (1)

Bill Tubbs
Bill Tubbs on 12 Oct 2021
Edited: Bill Tubbs on 12 Oct 2021
The answer by Steven Lord didn't work for me. I got this error:
Error using readtable (line 198)
Unknown Parameter 'VariableNamingRule'.
But the following solution (as explained here) works for me in MATLAB R2020a:
readtable(filename,'PreserveVariableNames',true)
  3 Comments
Steven Lord
Steven Lord on 12 Oct 2021
You could future proof your code now while it's fresh in your mind. Use verLessThan to determine if the MATLAB installation is older than release R2020b. Use PreserveVariableNames if it is and VariableNamingRule if it is not.
if verLessThan('matlab', '9.9') % 20b
parametersToUse = {'PreserveVariableNames', true};
else
parametersToUse = {'VariableNamingRule', 'preserve'};
end
fprintf("The option is %s and the value you have selected is %s.\n", ...
string(parametersToUse))
The option is VariableNamingRule and the value you have selected is preserve.
You can use parametersToUse as a comma-separated list.
parametersToUse{:}
ans = 'VariableNamingRule'
ans = 'preserve'

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