How do I convert a column to numeric?

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jakobjakob 2018-6-6

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评论： jakobjakob 2018-6-6

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variables.txt

See the image

I want to count with the 1st column, but I always get the message "Undefined operator" - "for input arguments or type 'cell'." What can I do about it? I think the column is not numeric, but I am not sure. Who can help me?

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Stephen23 2018-6-6

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Stephen23 2018-6-6

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编辑：Stephen23 2018-6-6

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Where C is your cell array:

V = str2double(C(:,1))

This assumes that there is no header, and that each cell of the first column contains one number stored as a char (using a dot, not comma).

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Stephen23 2018-6-6

编辑：Stephen23 2018-6-6

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@jakobjakob: The concept for indexing cell arrays is simple:

{} curly braces access the data inside the cells.
() parentheses access the cells themselves.

Just think of cell arrays like boxes: do you want to pick up the box (the cell, ()), or whatever that is inside the box (the data, {}). Sometimes you want to pick up the box, and sometimes you want to get out whatever is inside... each of these can be useful.

Therefore to access the contents of one cell you just need to use curly braces:

alldata{1,1} - 10

jakobjakob 2018-6-6