考虑以下矩阵：
[,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9] [,10] [,11] [,12] [,13] [,14] [,15] [,16] [,17] [,18] [,19] [,20]
[1,] 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
[2,] 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
[3,] 2 4 2 2 2 2 2 2 4 8 6 6 4 4 6 4 4 2 2 2
[4,] 2 2 2 4 4 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
[5,] 4 4 4 4 6 6 6 6 6 2 2 0 0 0 0 0 0 0 0 0
[6,] 4 4 4 2 2 2 4 6 6 2 2 2 2 2 2 2 2 2 0 0
[7,] 4 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
[8,] 4 6 4 6 4 6 4 4 6 2 2 0 0 0 0 0 0 0 0 0
[9,] 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
[10,] 4 6 4 4 6 8 14 10 14 8 10 8 8 6 6 4 0 0 0 0
[11,] 2 2 2 2 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0
[12,] 2 2 4 4 2 2 2 2 0 0 0 0 0 0 0 0 0 0 0 0
[13,] 2 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
[14,] 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
[15,] 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
[16,] 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
[17,] 2 4 6 4 2 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0
[18,] 2 4 4 4 6 4 8 10 8 14 16 14 20 24 26 16 16 20 20 22
[19,] 2 4 2 2 4 4 4 2 4 2 2 2 2 2 2 2 0 0 0 0
[20,] 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
如何从每列中提取0的总数？
答案 0 :(得分：3)
将colSums(trial == 0)应用于矩阵可以很好地总结每列中的0总数