In a function F(x,:), what does the colon represent?

I am new to Matlab.

I am trying to understand the following piece of code.

for g=1:GA.Ng    
    x(g,:)=GA.xmn(g)+(GA.xmx(g)-GA.xmn(g))*P(g,:);
end

what does the : indicate in x(g,:), P(g,:)? Thanks

Answer 1

[Star Strider]

‘... what does the : indicate in x(g,:), P(g,:)? ...’

In 2D arrays, it is necessary to address the row in the first element of the subscript reference, and the columns in the second. In both of the references you mention, the row is specified as whatever value ‘g’ is, and the isolated colon ‘:’ is shorthand indicating all the columns in the row designated by the value of ‘g’.

Answer 2

[Jan]

x(g,:) is an abbreviation for x(g, 1:end).

If X is an array with more than 2 dimensions, X(k, :) contains the values of the sub-array:

X = reshape([1,2,3,4, 11,12,13,14,  21,22,23,24], [2, 2, 3])
X(1, :)
X(2, :)

Please note, that these are Matlab basics and you can learn them efiiciently reading the "Getting Started" chapters of the documentation.