邏輯
1.因為是兩個集合綜合比較,所以使用union

2.並且如果有重複的name並且不為0 就更新他的amount。

假如list_A amount 是 20,list_B amount是10情況下該如何選擇呢?
所以我這邊取其最大值為準,所以使用group by name + max(amount)

Code

void Main()
{
	List<Wallet> list_A = new List<Wallet>(){
		new Wallet(){ name = "A" , amount = 0},
		new Wallet(){ name = "B" , amount = 0},
		new Wallet(){ name = "C" , amount = 0}
	};

	List<Wallet> list_B = new List<Wallet>(){
		new Wallet(){ name = "A" , amount = 10}
	};

	var result = list_A.Union(list_B).GroupBy(g => g.name).Select(s => new Wallet() {name=s.Key,amount=s.Max(m=>m.amount)}).ToList();
}

public class Wallet
{
	public string name { get; set; }
	public decimal amount { get; set; }
}

結果:

name	amount
A	10
B	0
C	0