如何从Excel电子表格中读取单个列？

I'm trying to read a single column from an Excel document. I'd like to read the entire column, but obviously only store the cells that have data. I also would like to try and handle the case, where a cell(s) in the column are empty, but it will read in later cell values if there's something farther down in the column. For example:I'm trying to read a single column from an Exce