ReadTable Producing ExtraVar Headers
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Hi,
I am trying to import a *.CSV file with headers using readtable(). It works ok except that beyond the 6th column, it fails to recognize the header strings and just puts "ExtraVar[#]". I'm trying to figure out if there is something wrong with the CSV file I'm using or if I need to configure readtable differently.
opts = detectImportOptions(filename);
opts.VariableNamesLine = 1; % Look for headers in first line
opts.Delimiter = ',';
logData = readtable(filename,opts,'ReadVariableNames',true);
I've attached a truncated version of my CSV file. When I run the code on it above, it produces a table with 6 of the 8 headers correct but column 7 and 8 are called ExtraVar1 and ExtraVar2.
3 个评论
Jamie Moon
2021-5-24
I forgot to show the output but here is what the cmd line display looks like when showing the table:
Bonus question: Any tips on how to interpret columns as a certain data type? As you can see my numbers are strings but I will be needed them as doubles.
Siddharth Bhutiya
2021-5-24
What MATLAB version are you using?
Jamie Moon
2021-5-24
采纳的回答
Jeremy Hughes
2021-5-24
Main issue is that the sample code is a bad practice. Once created by detectImportOptions, the options don't get updated based on the file if you change a property. So if you're updating delimiter, you're still using all other detected parameters which were not based on that delimiter.
opts = detectImportOptions(filename); %<------ is probably detecting the wrong number of variables
opts.VariableNamesLine = 1; % Look for headers in first line
opts.Delimiter = ','; %<---- Changes the delimiter, but nothing else.
Try this instead of setting the delimiter after the fact.
opts = detectImportOptions(filename,'Delimiter',',');
detectImportOptions uses the parameters passed into it to do better detection. So instead of trying to guess the delimiter, it knows ',' is the anwser, so it detects the headerlines, variables, datatypes, etc. based on comma. It may also be faster.
更多回答（1 个）
Sulaymon Eshkabilov
2021-5-24
Hi,
One more step is needed to get the numbers in double.
filename='sample_log_temp.csv';
opts = detectImportOptions(filename);
opts.VariableNamesLine = 1; % Look for headers in first line
opts.Delimiter = ',';
logData = readtable(filename,opts,'ReadVariableNames',true);
TIME=str2double(logData.UnixTime);
A_F=str2double(logData.AccelerometerFailure);
1 个评论
Arshey Dhangekar
2021-6-16
filename='WT_201120.csv';
opts = detectImportOptions(filename);
opts.VariableNamesLine = 1; % Look for headers in first line
opts.Delimiter = ',';
logData = readtable(filename,opts,'ReadVariableNames',true);
Hello it did not show reuquired header (Row 38 header in csv file) in Matlab using above code. Desired headers store number,time...till end.
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