Readtable and Readmatrix Ignore Specified Range and Produce Extra Variables

조회 수: 7 (최근 30일)
John
John 2025년 6월 20일
댓글: John 2025년 6월 20일
Ran in:
I have this very simple code:
type 2025-03-28_02-07_10-0.csv
Meas. ID, Time/Date, WV, Index, Sort #1, Sort #2, Sort #3, , 3/28/2025 2:21:22 PM, 632.8, 1.4753 , , , , , 3/28/2025 2:22:10 PM, 632.8, 1.4754 , , , , , 3/28/2025 2:22:58 PM, 632.8, 1.4754 , , , , , 3/28/2025 2:23:46 PM, 632.8, 1.4755 , , , , , 3/28/2025 2:24:34 PM, 632.8, 1.4752 , , , , , 3/28/2025 2:26:16 PM, 632.8, 1.4757 , , , , , 3/28/2025 2:27:04 PM, 632.8, 1.4757 , , , , , 3/28/2025 2:27:52 PM, 632.8, 1.4757 , , , , , 3/28/2025 2:28:40 PM, 632.8, 1.4755 , , , , , 3/28/2025 2:29:28 PM, 632.8, 1.4756 , , , , , 3/28/2025 2:31:29 PM, 632.8, 1.4756 , , , , , 3/28/2025 2:32:17 PM, 632.8, 1.4756 , , , , , 3/28/2025 2:33:05 PM, 632.8, 1.4754 , , , , , 3/28/2025 2:33:53 PM, 632.8, 1.4756 , , , , , 3/28/2025 2:34:41 PM, 632.8, 1.4754 , , , , , 3/28/2025 2:36:08 PM, 972.3, 1.4685 , , , , , 3/28/2025 2:36:56 PM, 972.3, 1.4683 , , , , , 3/28/2025 2:37:44 PM, 972.3, 1.4687 , , , , , 3/28/2025 2:38:32 PM, 972.3, 1.4687 , , , , , 3/28/2025 2:39:20 PM, 972.3, 1.4684 , , , , , 3/28/2025 2:40:44 PM, 972.3, 1.4813 , , , , , 3/28/2025 2:41:32 PM, 972.3, 1.4683 , , , , , 3/28/2025 2:42:20 PM, 972.3, 1.4684 , , , , , 3/28/2025 2:43:07 PM, 972.3, 1.4685 , , , , , 3/28/2025 2:43:55 PM, 972.3, 1.4685 , , , , , 3/28/2025 2:45:19 PM, 972.3, 1.4679 , , , , , 3/28/2025 2:46:07 PM, 972.3, 1.4696 , , , , , 3/28/2025 2:46:55 PM, 972.3, 1.4700 , , , , , 3/28/2025 2:47:43 PM, 972.3, 1.4697 , , , , , 3/28/2025 2:48:31 PM, 972.3, 1.4697 , , , , , 3/28/2025 2:50:53 PM, 403.2, 1.4929 , , , , , 3/28/2025 2:51:41 PM, 403.2, 1.4925 , , , , , 3/28/2025 2:52:29 PM, 403.2, 1.4926 , , , , , 3/28/2025 2:53:17 PM, 403.2, 1.4928 , , , , , 3/28/2025 2:54:05 PM, 403.2, 1.4925 , , , , , 3/28/2025 2:55:26 PM, 403.2, 1.4922 , , , , , 3/28/2025 2:56:14 PM, 403.2, 1.4923 , , , , , 3/28/2025 2:57:02 PM, 403.2, 1.4923 , , , , , 3/28/2025 2:57:50 PM, 403.2, 1.4926 , , , , , 3/28/2025 2:58:38 PM, 403.2, 1.4925 , , , , , 3/28/2025 3:00:32 PM, 403.2, 1.4928 , , , , , 3/28/2025 3:01:20 PM, 403.2, 1.4926 , , , , , 3/28/2025 3:02:07 PM, 403.2, 1.4928 , , , , , 3/28/2025 3:02:55 PM, 403.2, 1.4927 , , , , , 3/28/2025 3:03:43 PM, 403.2, 1.4924 , , , , Mean, , , 1.4792 , Std Dev, , , .0100 , % Std Dev, , , 0.68, Count, , , 45, Min, , , 1.4679 , Max, , , 1.4929 ,
in1 = readtable('2025-03-28_02-07_10-0.csv', 'ReadVariableNames', false, 'Range', 'C2:C3')
in1 = 2×5 table
Var1 ExtraVar1 ExtraVar2 ExtraVar3 Var5 _____ _________ _________ _________ _____ 632.8 {' '} {' '} {' '} {' '} 632.8 {' '} {' '} {' '} {' '}
in2 = readtable('2025-03-28_02-07_10-0.csv', 'ReadVariableNames', false, 'Range', 'C2:D3')
in2 = 2×6 table
Var1 Var2 ExtraVar1 ExtraVar2 Var5 Var6 _____ ______ _________ _________ _____ _____ 632.8 1.4753 {' '} {' '} {' '} {' '} 632.8 1.4754 {' '} {' '} {' '} {' '}
stupid_matlab = readtable('PATH', 'ReadVariableNames', false, 'Range', strcat('C2:D', string(ri_length)));
Unrecognized function or variable 'ri_length'.
However, it completely ignores the column portion of the range I give it. Changing the number part of the specified range changes the number of rows, but it always produces four extra columns. If I specify C2:C3, I get five columns. If I specify C2:D3, I get six columns. I have not idea where it is getting the extra columns from. I have also tried "readmatrix" and it does the exact same thing. I've attatched the .csv, but I've opened it directly and in excel and don't see anything wrong.

이 질문에 답변하려면 로그인하십시오.

채택된 답변

Dyuman Joshi
Dyuman Joshi 2025년 6월 20일
Ran in:
From what I have understood of your query, you need to specify that you don't require Extra columns -
readtable adds variable by default (See here for documentation entry for the same)
in = readtable('2025-03-28_02-07_10-0.csv', 'ReadVariableNames', false)
in = 51×8 table
Var1 Var2 Var3 Var4 Var5 Var6 Var7 Var8 __________ ______________________ _____ ______ ____ ____ ____ _____ {0×0 char} 03/28/2025 02:21:22 PM 632.8 1.4753 NaN NaN NaN {' '} {0×0 char} 03/28/2025 02:22:10 PM 632.8 1.4754 NaN NaN NaN {' '} {0×0 char} 03/28/2025 02:22:58 PM 632.8 1.4754 NaN NaN NaN {' '} {0×0 char} 03/28/2025 02:23:46 PM 632.8 1.4755 NaN NaN NaN {' '} {0×0 char} 03/28/2025 02:24:34 PM 632.8 1.4752 NaN NaN NaN {' '} {0×0 char} 03/28/2025 02:26:16 PM 632.8 1.4757 NaN NaN NaN {' '} {0×0 char} 03/28/2025 02:27:04 PM 632.8 1.4757 NaN NaN NaN {' '} {0×0 char} 03/28/2025 02:27:52 PM 632.8 1.4757 NaN NaN NaN {' '} {0×0 char} 03/28/2025 02:28:40 PM 632.8 1.4755 NaN NaN NaN {' '} {0×0 char} 03/28/2025 02:29:28 PM 632.8 1.4756 NaN NaN NaN {' '} {0×0 char} 03/28/2025 02:31:29 PM 632.8 1.4756 NaN NaN NaN {' '} {0×0 char} 03/28/2025 02:32:17 PM 632.8 1.4756 NaN NaN NaN {' '} {0×0 char} 03/28/2025 02:33:05 PM 632.8 1.4754 NaN NaN NaN {' '} {0×0 char} 03/28/2025 02:33:53 PM 632.8 1.4756 NaN NaN NaN {' '} {0×0 char} 03/28/2025 02:34:41 PM 632.8 1.4754 NaN NaN NaN {' '} {0×0 char} 03/28/2025 02:36:08 PM 972.3 1.4685 NaN NaN NaN {' '}
%Specifying a range
in = readtable('2025-03-28_02-07_10-0.csv', 'ReadVariableNames', false, 'Range', 'B1:H5')
in = 4×7 table
Var1 Var2 Var3 Var4 Var5 Var6 ExtraVar1 ______________________ _____ ______ ____ ____ ____ _________ 03/28/2025 02:21:22 PM 632.8 1.4753 NaN NaN NaN {' '} 03/28/2025 02:22:10 PM 632.8 1.4754 NaN NaN NaN {' '} 03/28/2025 02:22:58 PM 632.8 1.4754 NaN NaN NaN {' '} 03/28/2025 02:23:46 PM 632.8 1.4755 NaN NaN NaN {' '}
%Specifying a range with no extra variable creation
in = readtable('2025-03-28_02-07_10-0.csv', 'ReadVariableNames', false, 'Range', 'B1:H5', ...
'ExtraColumnsRule', 'ignore')
in = 4×6 table
Var1 Var2 Var3 Var4 Var5 Var6 ______________________ _____ ______ ____ ____ ____ 03/28/2025 02:21:22 PM 632.8 1.4753 NaN NaN NaN 03/28/2025 02:22:10 PM 632.8 1.4754 NaN NaN NaN 03/28/2025 02:22:58 PM 632.8 1.4754 NaN NaN NaN 03/28/2025 02:23:46 PM 632.8 1.4755 NaN NaN NaN

추가 답변 (2개)

dpb
dpb 2025년 6월 20일
Ran in:
d=dir('*.csv');
opt=detectImportOptions(d.name);
tin=readtable(d.name,'Range','C2:C3','ExtraColumnsRule','ignore')
tin = 2×1 table
Var1 _____ 632.8 632.8
I don't know if Mathworks would classify the behavior as a bug or not, but is unexpected, granted. Probably worth submitting a report as a quality of implementation issue. It's complicated, so not terribly surprising there are still some warts hanging about.
You can give it a little extra help as above to avoid the issue...
Matt J
Matt J 2025년 6월 20일
편집: Matt J 2025년 6월 20일
Ran in:
When I save as .xlsx, it seems to work okay,
in1 = readtable('2025-03-28_02-07_10-0.xlsx', 'ReadVariableNames', false, 'Range', 'C2:C3')
in1 = 2×1 table
Var1 _____ 632.8 632.8

카테고리

Help Center 및 File Exchange에서 Graphics Object Programming에 대해 자세히 알아보기

태그

제품


릴리스

R2025a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by