How to extract strings from a table?

129 次查看（过去 30 天）
Alex Gimeno
Alex Gimeno 2019-10-2
评论： Simon Schmidt 2021-4-29
Hi all,
I know this is likely a very basic question, but I can't seem to figure it out. I want to extract strings from a table and put them in their own array. My code is here:
IDs=1718; %Define how many IDS there are in the total table; this was determined from the Excel sheet
masterCountSheet = readtable('Tasks_Count_060118 (streamlined).xlsx'); %Create table containing master count sheet data
IDDataArray=zeros(1,IDs)
for i=1:IDs
IDDataArray(i)=masterCountSheet(i,1)
end
However, whenever I reference a specific cell in the table, I get a cell array returned, not a string. Any ideas as to why and how to fix this?
  2 个评论
David K.
David K. 2019-10-2
If IDDaraArray at the end is a cell array of strings then you should be able to just do
output = string(IDDataArray)

请先登录，再进行评论。

请先登录，再回答此问题。

采纳的回答

Guillaume
Guillaume 2019-10-2
编辑：Guillaume 2019-10-2
Why is the size of the array hardcoded (which means the code will break if something change with the file) instead of just asking matlab for it?
In any case, the loop is completely unnecessary:
IDDataArray = masterCountSheet.(1);
%or
IDDataArray = masterCountSheet{:, 1};
%or
IDDataArray = masterCountSheet.NameOf1stVariableInTable;
Note that
masterCountSheet(i,1)
returns a table (not a cell array) which consist of just the ith row and first variable of masterCountSheet. To access the content of a table you use {} indexing or . indexing, not ().
Also note that if that first variable indeed contain strings, then initialising the array with zeros is an error. zeros creates a numerical array, not a string array.

更多回答（1 个）

Anthony Dave
Anthony Dave 2020-11-27
编辑：Anthony Dave 2020-11-27
@David K and @Walter Roberson's answers enlightened me. You can use the following code in this example.
IDDataArray = string(masterCountSheet{1:IDs,1});
If you just want to read data in all rows, try:
IDDataArray = string(masterCountSheet{:,1});
  1 个评论
Simon Schmidt
Simon Schmidt 2021-4-29
Hi! What if only want the first 3 characters (instead of the whole string) of every row?

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Numeric Types 的更多信息

标签

Community Treasure Hunt

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

Start Hunting!

Translated by