Appending string to Matlab array

How do I append a string to a Matlab array column wise开发者_运维知识库?

Here is a small code snippet of what I am trying to do:

for_loop
  filename = 'string';
  name=[name; filename]
end

---

You need to use cell arrays. If the number of iterations are known beforehand, I suggest you preallocate:

N = 10;
names = cell(1,N);
for i=1:N
    names{i} = 'string';
end

otherwise you can do something like:

names = {};
for i=1:10
    names{end+1} = 'string';
end

---

As other answers have noted, using cell arrays is probably the most straightforward approach, which will result in your variable name being a cell array where each cell element contains a string.

However, there is another option using the function STRVCAT, which will vertically concatenate strings. Instead of creating a cell array, this will create a 2-D character matrix with each row containing one string. STRVCAT automatically pads the ends of the strings with spaces if necessary to correctly fill the rows of the matrix:

>> string1 = 'hi';
>> string2 = 'there';
>> S = strvcat(string1,string2)

S =

hi
there

---

As noted elsewhere, in MATLAB all strings in an array must be the same length. To have strings of different lengths, use a cell array:

name = {};
for i = somearray
  name = [name; {string}];
end

---

Use strcat function to append using one line code without using loop:

A={'food','banana','orange'}

A = 'food' 'banana' 'orange'

A = strcat(A,'s')

A = 'foods' 'bananas' 'oranges'

---

name=[];
for_loop
    filename = 'string';
    name=[name; {filename}];
end

---

For completeness, one should also mention the new string class introduced in MATLAB R2016b; a container for text data along with a set of functions for easy text manipulation.

To compare it against my other example, here is how to allocate a string array:

N = 10;
names = strings(1,N);
for i=1:N
    names(i) = 'string';
end

And here is how to dynamically expand the array without preallocation:

names = strings(0);
for i=1:10
    names(end+1) = 'string';
end

(Of course if the strings are all the same or form a sequence with a pattern, there are better ways to create the array without a loop. The above was just an example of filling the array one-by-one).

The string container can also convert to/from character arrays and cell arrays of chars.

---

If you are using two arrays like below (A and B) you can append them like what you do with other matrices.

A = {'a' ; 'b' ; 'c'};
B = {'1' ; '2' ; '3'};
Result = { A{:,1} ; B{:,1} }

Result = 

'a'    'b'    'c'
'1'    '2'    '3'

---

I know that this is an old thread, but it seems as if you don't even need a loop if this is all you are doing in the loop. Could you just use a vertical concatenation?

   mmm = {'str1'; 'str2'; 'str3'};
   temp = {'a'; 'b'; 'c'};

   mmm = [mmm; temp]

mmm = 

    'str1'
    'str2'
    'str3'
    'a'
    'b'
    'c'

---

You are going the right way. Use {} to build a cell array, like this

stringtable = 'a string';
for i = 1:3
    stringtable = {stringtable;new_string(i)}
end

should do what you want.