Multiply matrix column by an equation

I used A= readmatrix() to create a very large matrix from data in an excel file and now have:

[x1 z1

x2 z2

x3 z3 ] etc.

I'd like to take all the current "x" values in column 1 and apply the funtion y=ln(1+x) and create a new matrix with:

[y1 z1

y2 z2

y3 z3] etc.

I tried using a for loop, but didn't know how to input the existing x values into the function.

Any advice welcome, please let me know if you'd like more info.

Answer 1

[Fangjun Jiang]

A=[1:3;10:10:30]'
A(:,1)=log(A(:,1)+1)