Some fast-food companies also cannibalised their own profits by trying to give customers better value.
这个句子中的by有哪些含义？该怎么样理解？
by 用于表示方法、方法，意思是“用，靠，通过，凭着”等，by doing sth 意思是“通过做某事”的方法（方法）。如：By using the Internet you can do your shopping from home. 用因特网你可以在家购物。（摘自《麦克米伦高阶英汉双解词典》）