Append to an array

Hi all,

I have a function called details, where the user enters his name, and the details are stored in the array, say "name". Each time a name is entered it should get appended to the array.

At any point, the user can cancel entering the details and do other computations. Then again the user can start entering the details. In this case, it should get appended to the "name" array that is already existing.

At the beginning of the session, the array "name" should be empty.

[Azzi Abdelmalek]

post your code

[Omar Ahmed]

Create a 3x3 matrix A in which all the elements are 1, and create a 2x2 matrix B in which all the elements are 5. Then, add elements to the matrix A by appending the matrix B such that A will be:

A = [ 1 1 1 0 0; 1 1 1 0 0; 1 1 1 0 0; 0 0 0 5 5; 0 0 0 5 5]

I need to slove it .

[Omar Ahmed]

Haw I can to my code ???

Answer 1

[Yatin]

Hi,

A possible solution to your problem could be something like this. Set the array as empty initially(beginning of the session).

nameArray = {};

You can then append the entries in the array as follows:

nameArray = [nameArray, 'Name you want to append'];

This uses the concept of cell array. You might want to refer to the documentation on cell arrays for more information. http://www.mathworks.com/help/matlab/cell-arrays.html

[Cooper Harris]

this is an awful answer. does not address how to iteratively update an array ("list" in python). this simply redefines the array and erases past values. the link you posted was helpful though!

[James Tursa]

"... this simply redefines the array and erases past values ..."

Really? Did you try it?

[Steven Lord]

If you run both commands over and over again, nameArray will keep only the last name entered.

If you run the first command once to initialize the variable then run only the second line repeatedly to append to the cell array, it will do what the original poster asked.

[Bill Tubbs]

Sad that this is the only solution since it's not efficient (reallocates memory each iteration) but what can you do... Thanks!

[bla bla]

@Bill Tubbs maybe try nameArray(end+1) = {'name to be appended'}; should be a more efficient way of doing it

[Xuzhaoqiu Zeng]

testFactor = 194225602
testStart = 3928
tic
mytest = [testStart];
for i = 1:100000
    mytest = [mytest, testStart];
end
toc

tic
mytest = [testStart];
for i = 1:100000
    mytest(end+1) = testStart;
end
toc

The result is :

2.024820

0.011121

list = [list, appendedNumber] is ridiculous.

Answer 2

[Vinaya Babu Yerneni]

Firstly you need to clarify whether you need to append strings or integer or string and integer

for only strings

name=input('What is your name? ', 's');

age=input('What is your age? ',"s");

hometown=input('What is your hometown? ', 's');

sport=input('What is your favorite sport? ', 's');

Temptex2=append(name,age,hometown,sport)