I have a matrix A=[1,2; 2,3; 3,4;1,2],

I wanted to return duplicated rows (here 1,2), no of repetitions (here 1) and the row index of the first occurrence (here 1st row)

I have tried many thing with unique, but nothing worked out

I have a matrix A=[1,2; 2,3; 3,4;1,2],

I wanted to return duplicated rows (here 1,2), no of repetitions (here 1) and the row index of the first occurrence (here 1st row)

I have tried many thing with unique, but nothing worked out

One small package for such things is:

```
julia> using GroupSlices
julia> A = [1 2; 2 3; 3 4; 1 2.0] # edited
4×2 Matrix{Float64}:
1.0 2.0
2.0 3.0
3.0 4.0
1.0 2.0
julia> groupslices(A, dims=1)
4-element Vector{Int64}:
1
2
3
1
julia> groupinds(ans)
3-element Vector{Vector{Int64}}:
[1, 4]
[2]
[3]
julia> filter(is -> length(is)>1, ans)
1-element Vector{Vector{Int64}}:
[1, 4]
```

1 Like

Thanks , is there any way to get the no of repetitions?

This one gives my the repeated numbers and the row value

“” countmap(collect(eachrow(A))) “”"

Extended example - what number do you want?

```
B = [1 2; 2 3; 3 4; 1 2.0; 2 3; 2 3]
y = countmap(collect(eachrow(B)))
sum(x -> x>1 ? x : 0, values(y)) # = 5 : total number of repeated rows
sum(>(1), values(y)) # = 2 : number of distinct rows repeated
```

```
A=[1 2; 2 3; 3 4; 1 2.0;1 2;1 3;3 4]
julia> function norepandfo(A)
grp=[findall(==(r),eachrow(A)) for r in unique(eachrow(A))]
collect(zip(length.(grp).-1, first.(grp)))
end
norepandfo (generic function with 1 method)
julia> norepandfo(A)
4-element Vector{Tuple{Int64, Int64}}:
(2, 1)
(0, 2)
(1, 3)
(0, 6)
```

This worked for me

Thanks all

this version of the function returns to a generator that can be collected or filtered:

```
function noofrepandfo(A)
grp=[findall(==(r),eachrow(A)) for r in unique(eachrow(A))]
zip(length.(grp).-1, first.(grp))
end
[t for t in noofrepandfo(A)]
[t for t in noofrepandfo(A) if first(t)!=0]
```

```
julia> [t for t in noofrepandfo(A) if first(t)!=0]
2-element Vector{Tuple{Int64, Int64}}:
(2, 1)
(1, 3)
julia> [t for t in noofrepandfo(A)]
4-element Vector{Tuple{Int64, Int64}}:
(2, 1)
(0, 2)
(1, 3)
(0, 6)
```