Inserting NaN for unknown data

I have one array say from (1:10)'

I have a one more matrix [2, 100; 3, 450; 5, 500; 7, 800; 8, 850];

I want my final answer to be [1, NaN; 2, 100; 3, 450; 4, NaN; 5, 500; 6, NaN; 7, 800; 8, 850; 9, NaN; 10, NaN]

Answer 1

[KSSV]

clc; clear all ;
C = [1, NaN; 2, 100; 3, 450; 4, NaN; 5, 500; 6, NaN; 7, 800; 8, 850; 9, NaN; 10, NaN] ; 
A = (1:10)' ; 
B = [2, 100; 3, 450; 5, 500; 7, 800; 8, 850];

iwant = NaN(10,2) ; 
iwant(:,1) = A ; 
[c,ia] = ismember(A,B(:,1)) ; 
iwant(c,2) = B(:,2) ; 

[Debasish Jana]

Thanks. I thought it could be done in 1 or 2 lines of code