如何在Julia中搜索和处理稀疏矩阵

我有一个大的稀疏矩阵。我想做的是能够做两件事：

查找只有一个非零值的行。让我们调用它的行索引

idx

归零列

idx

，在1中找到。由于矩阵很大，我希望能有效地完成这项工作

---

我已经试过阅读，但我也看不出怎么做。

如果我理解正确，这应该可以：

julia> using SparseArrays

# Dummy data
julia> A = sparse([1, 1, 2, 2, 3, 3], [1, 2, 3, 1, 2, 3], [2, 3, 0, 0, 0, 5])
3×3 SparseMatrixCSC{Int64,Int64} with 6 stored entries:
  [1, 1]  =  2
  [2, 1]  =  0
  [1, 2]  =  3
  [3, 2]  =  0
  [2, 3]  =  0
  [3, 3]  =  5

# Count non-zero elements across rows
julia> using StatsBase

julia> valcounts = countmap(A.rowval[A.nzval .!= 0])
Dict{Int64,Int64} with 2 entries:
  3 => 1
  1 => 2

# Find the row(s) with only one non-zero element
julia> [k for k ∈ keys(valcounts) if valcounts[k] == 1]
1-element Array{Int64,1}:
 3

# Set the non-zero element in the third row to zero
julia> A[3, A[3, :] .> 0] .= 0
1-element view(::SparseMatrixCSC{Int64,Int64}, 3, [3]) with eltype Int64:
 0

julia> A
3×3 SparseMatrixCSC{Int64,Int64} with 6 stored entries:
  [1, 1]  =  2
  [2, 1]  =  0
  [1, 2]  =  3
  [3, 2]  =  0
  [2, 3]  =  0
  [3, 3]  =  0

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我认为这是第3行的零，但我想在本例中是第3列的零。啊，这很公平，读得不够仔细-你可能想在发生零的行和列之间交换。