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 个评论
Steven Lord
2016-4-28
What specific names were modified?
Were any of the names in your spreadsheet duplicates?
Were any of the names that were modified MATLAB keywords (as listed by the iskeyword function?)
Tejas Sonavane
2016-4-28
编辑：Image Analyst
2016-4-28
Walter Roberson
2016-4-28
Would it be practical to post the spreadsheet, or at least an initial portion of it?
Tejas Sonavane
2016-4-28
编辑：Tejas Sonavane
2016-4-28
Tejas Sonavane
2016-4-28
采纳的回答
Image Analyst
2016-4-28
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 个评论
Tejas Sonavane
2016-4-28
Image Analyst
2016-4-29
No. ans is just the fieldnames that get spit out. and is not an object or class so it won't have any properties or methods at all. You can do this with t though:
t = readtable('VAT_Experiment_Sheet_Assign_Table_Structure_Units.xlsx')
fieldnames(t) % Show column headers
methods(t) % Show functions t can do.
t.Properties.VariableNames
Again, I don't see any problems.
Raed Bourisli
2020-12-14
Variable names in the spreadsheet cannot have spaces.
Steven Lord
2020-12-14
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
更多回答（1 个）
Bill Tubbs
2021-10-12
编辑：Bill Tubbs
2021-10-12
The answer by Steven Lord didn't work for me. I got this error:
Error using readtable (line 198)
Unknown Parameter 'VariableNamingRule'.
readtable(filename,'PreserveVariableNames',true)
3 个评论
Steven Lord
2021-10-12
The PreserveVariableNames property (which could only take on values true and false) was replaced in release R2020b with the "VariableNamingRule" name-value pair (which had 'preserve' and 'modify' as valid values) as stated in the Release Notes. That's the change I mentioned in square brackets in my comment on Image Analyst's accepted answer.
Bill Tubbs
2021-10-12
Ah, sorry I missed that. Thanks. I guess I will have to update my code next year when I upgrade MATLAB...
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))
You can use parametersToUse as a comma-separated list.
parametersToUse{:}
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