deleteat! where drop is a column (JuliaData#3304)

NEWS.md

@@ -16,6 +16,12 @@
 * `describe` now has `:sum` available as a descriptive statistic.
  ([#3303](https://github.com/JuliaData/DataFrames.jl/pull/3303))
 
+## Bug fixes
+
+* `deleteat!` correctly handles the situation when vector of rows to be dropped
+ from a data frame is its column or might alias with some of its columns
+ ([#3304](https://github.com/JuliaData/DataFrames.jl/pull/3304))
+
 # DataFrames.jl v1.5 Release Notes
 
 ## New functionalities

src/dataframe/dataframe.jl

@@ -904,6 +904,10 @@ function _deleteat!_helper(df::DataFrame, drop)
  return df
  end
 
+ if any(c -> c === drop || Base.mightalias(c, drop), cols)
+ drop = copy(drop)
+ end
+
  n = nrow(df)
  col1 = cols[1]
  deleteat!(col1, drop)

test/dataframe.jl

@@ -518,6 +518,13 @@ end
  df = DataFrame(a=1, b=3.0)
  @test isempty(deleteat!(df, true:true))
 
+ df = DataFrame(a=[false, true, true], b=1:3, c=4:6)
+ @test deleteat!(df, df.a) == DataFrame(a=false, b=1, c=4)
+ df = DataFrame(a=1:3, b=[false, true, true], c=4:6)
+ @test deleteat!(df, df.b) == DataFrame(a=1, b=false, c=4)
+ df = DataFrame(a=1:3, b=4:6, c=[false, true, true])
+ @test deleteat!(df, df.c) == DataFrame(a=1, b=4, c=false)
+
  Random.seed!(1234)
  for t in 0:0.005:1.0
  # two columns are needed as the second column is affected