How to update a value in a different location from a matrix after performing check at one location in MATLAB?

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KenL 2016-10-4

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评论： TallBrian 2016-10-4

I have a matrix as follow.

file={'No','Question','Length';'1','how are you?','';'2','What is your name?','';'3','Where do you stay?','';'4','How old are you?',''}

I want to figure out the length for all the text columns but the returned length is always 1. Please advise. TQ.

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Answer 1

TallBrian 2016-10-4

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在 MATLAB Online 中打开

What you have is a cell array. If you want to do a function on every element of a cell array you can use cellfun. Here if you would like to calculate the length of each element of the cell array you could try the following code:

my_lengths = cellfun(@(x) length(x), file)

Here, x is each element of file treated individually.

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KenL 2016-10-4

Can any help, pls?

TallBrian 2016-10-4

在 MATLAB Online 中打开

Ken, it looks like you have not entered the command correctly. You need to enter the command as I indicated in the original answer. The error you receive seems to indicate you are trying to run length on raw(b,2), I am not sure what this is. You need to run length on x which is what cellfun creates for each element of file.

>> file={'No','Question','Length';'1','how are you?','';'2','What is your name?','';'3','Where do you stay?','';'4','How old are you?',''}
file = 
      'No'    'Question'              'Length'
      '1'     'how are you?'          ''      
      '2'     'What is your name?'    ''      
      '3'     'Where do you stay?'    ''      
      '4'     'How old are you?'      ''      
>> cellfun(@(x) length(x), file)
ans =
       2     8     6
       1    12     0
       1    18     0
       1    18     0
       1    16     0