Error changing data in table from char to double

2 次查看（过去 30 天）
Zac Lingen
Zac Lingen 2019-4-16
评论： Star Strider 2019-4-18
*See attached data set for reference
I am importing the data set and trying to change the variable type for the second column, "GROSS_QTY" from a char to a double. I am following the example Matlab published (Here - "Detect and Use Import Options for Text Files").
Here is the code:
opts = detectImportOptions('DateAndQuantity.csv');
getvaropts(opts,{'GROSS_QTY'});
opts = setvartype(opts,{'GROSS_QTY'},'double');
opts.SelectedVariableNames = {'GROSS_QTY'};
qntyTable = readtable('DateAndQuantity.csv');
summary(T)
The summary outputs the following:
Variables:
GROSS_QTY: 105x1 cell array of character vectors
Per the example provided by Matlab, that variable should be a double. Can anyone explain what is happening?

请先登录，再回答此问题。

采纳的回答

Star Strider
Star Strider 2019-4-16
编辑：Star Strider 2019-4-17
The ‘GROSS_QTY’ problem is relatively easy to solve:
[~,S] = xlsread('DateAndQuantity.csv');
G_Q = sscanf([S{2:end,2}],'%d;');
I cannot get any of the date functions to import the dates correctly. I suspect the problems are the duplicated single quotes and perhaps that the months are in all capitalis.
EDIT —
I was able to import all except the first and last dates to a datetime array with this code:
S_Dv = strrep([S{2:end,1}], '''''', ',');
S_Ds = strsplit(S_Dv, ',');
D_S = cellfun(@(x)datetime(x, 'Format','dd-MMM-yyyy'), S_Ds(2:end-1))';
You may have to do those two manually. (NOTE the transpose to get them as a column vector.)
  4 个评论
显示 2更早的评论
Zac Lingen
Zac Lingen 2019-4-18
At the moment, the output of this script will be somewhat simple. However, I will eventually integrating this script's output into other applications so I will handle that problem at a later date.
Thank you again for your help

请先登录，再进行评论。

更多回答（1 个）

A. Sawas
A. Sawas 2019-4-16
编辑：A. Sawas 2019-4-16
This is to explain what is happening when using the function detectImportOptions:
It seems the csv file format is inconsistent. Therefore, detectImportOptions is not able to guess the right format. The function only detects the comma ',' delimiter while the last column ends with semicolon ';' is not detected. To fix this issue, explicitly specify the delimiters.
However, this will cause the detectImportOptions to not correctly detect the columns names (because there is only a comma in the headers line) so you also need to specify them.
opts = detectImportOptions('DateAndQuantity.csv', 'Delimiter', {',', ';'});
opts.VariableNames(2) = {'GROSS_QTY'}; % specify the column name
opts.ExtraColumnsRule = 'ignore'; % do not add other columns than the selected one

类别

在 Help Center 和 File Exchange 中查找有关 Data Import from MATLAB 的更多信息

标签

产品


版本

R2019a

Community Treasure Hunt

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

Start Hunting!

Translated by