问题描述
我正在尝试按如下方式创建 DataFrame：
[root@srvr0 ~]# julia
_
_ _ _(_)_ | Documentation: https://docs.julialang.org
(_) | (_) (_) |
_ _ _| |_ __ _ | Type "?" for help,"]?" for Pkg help.
| | | | | | |/ _` | |
| | |_| | | | (_| | | Version 1.4.1 (2020-04-14)
_/ |\__'_|_|_|\__'_| | Official https://julialang.org/ release
|__/ |
julia> using DataFrames
julia> using DelimitedFiles
julia> P,H = readdlm("programminglanguages.csv",',';header=true);
julia> P
73×2 Array{Any,2}:
1951 "Regional Assembly Language"
1952 "Autocode"
1954 "IPL"
1955 "FLOW-MATIC"
1957 "FORTRAN"
1957 "COMTRAN"
1958 "LISP"
1958 "ALGOL 58"
1959 "FACT"
1959 "COBOL"
1959 "RPG"
1962 "APL"
1962 "Simula"
1962 "snobol"
1963 "CPL"
1964 "Speakeasy"
1964 "BASIC"
1964 "PL/I"
1966 "JOSS"
1967 "BCPL"
1968 "logo"
1969 "B"
1970 "Pascal"
1970 "Forth"
⋮
1995 "Ada 95"
1995 "Java"
1995 "Delphi "
1995 "JavaScript"
1995 "PHP"
1997 "Rebol"
2000 "ActionScript"
2001 "C#"
2001 "D"
2002 "Scratch"
2003 "Groovy"
2003 "Scala"
2005 "F#"
2006 "PowerShell"
2007 "Clojure"
2009 "Go"
2010 "Rust"
2011 "Dart"
2011 "Kotlin"
2011 "Red"
2011 "Elixir"
2012 "Julia"
2014 "Swift"
julia> H
1×2 Array{AbstractString,2}:
"year" "language"
julia> typeof(P)
Array{Any,2}
julia> typeof(H)
Array{AbstractString,2}
julia> vec(H)
2-element Array{AbstractString,1}:
"year"
"language"
julia> typeof(vec(H))
Array{AbstractString,1}
julia> DataFrame(P,H)
但我收到以下错误：
ERROR: MethodError: no method matching DataFrame(::Array{Any,2},::Array{AbstractString,2})
Closest candidates are:
DataFrame(::AbstractArray{T,2} where T) at /opt/julia/julia-1.4.1/share/julia/stdlib/v1.4/packages/DataFrames/yH0f6/src/dataframe/dataframe.jl:209
DataFrame(::AbstractArray{T,2} where T,::AbstractArray{Symbol,1}; makeunique) at /opt/julia/julia-1.4.1/share/julia/stdlib/v1.4/packages/DataFrames/yH0f6/src/dataframe/dataframe.jl:209
DataFrame(::T; copycols) where T at /opt/julia/julia-1.4.1/share/julia/stdlib/v1.4/packages/DataFrames/yH0f6/src/other/tables.jl:23
Stacktrace:
[1] top-level scope at REPL[10]:1
更新 1： 参考 Dr.Bogumils 解决方案：
julia> DataFrame(P,vec(H))
ERROR: MethodError: no method matching DataFrame(::Array{Any,1})
Closest candidates are:
DataFrame(::AbstractArray{T,1}; makeunique) at /opt/julia/julia-1.4.1/share/julia/stdlib/v1.4/packages/DataFrames/yH0f6/src/dataframe/dataframe.jl:209
DataFrame(::T; copycols) where T at /opt/julia/julia-1.4.1/share/julia/stdlib/v1.4/packages/DataFrames/yH0f6/src/other/tables.jl:23
Stacktrace:
[1] top-level scope at REPL[13]:1
julia>
请指导我使用 readdlm 对象的标头创建 Datafrome。
更新 2：
我是通过反复试验的方法得到的：
julia> df1=DataFrame(P,Symbol.(vec(H)))
73×2 DataFrame
│ Row │ year │ language │
│ │ Any │ Any │
├─────┼──────┼────────────────────────────┤
│ 1 │ 1951 │ Regional Assembly Language │
│ 2 │ 1952 │ Autocode │
│ 3 │ 1954 │ IPL │
│ 4 │ 1955 │ FLOW-MATIC │
│ 5 │ 1957 │ FORTRAN │
│ 6 │ 1957 │ COMTRAN │
│ 7 │ 1958 │ LISP │
│ 8 │ 1958 │ ALGOL 58 │
│ 9 │ 1959 │ FACT │
│ 10 │ 1959 │ COBOL │
│ 11 │ 1959 │ RPG │
│ 12 │ 1962 │ APL │
│ 13 │ 1962 │ Simula │
│ 14 │ 1962 │ snobol │
│ 15 │ 1963 │ CPL │
│ 16 │ 1964 │ Speakeasy │
│ 17 │ 1964 │ BASIC │
│ 18 │ 1964 │ PL/I │
│ 19 │ 1966 │ JOSS │
│ 20 │ 1967 │ BCPL │
│ 21 │ 1968 │ logo │
⋮
│ 52 │ 1995 │ Java │
│ 53 │ 1995 │ Delphi │
│ 54 │ 1995 │ JavaScript │
│ 55 │ 1995 │ PHP │
│ 56 │ 1997 │ Rebol │
│ 57 │ 2000 │ ActionScript │
│ 58 │ 2001 │ C# │
│ 59 │ 2001 │ D │
│ 60 │ 2002 │ Scratch │
│ 61 │ 2003 │ Groovy │
│ 62 │ 2003 │ Scala │
│ 63 │ 2005 │ F# │
│ 64 │ 2006 │ PowerShell │
│ 65 │ 2007 │ Clojure │
│ 66 │ 2009 │ Go │
│ 67 │ 2010 │ Rust │
│ 68 │ 2011 │ Dart │
│ 69 │ 2011 │ Kotlin │
│ 70 │ 2011 │ Red │
│ 71 │ 2011 │ Elixir │
│ 72 │ 2012 │ Julia │
│ 73 │ 2014 │ Swift │
解决方法
这很难准确回答，但错误只是告诉您不能将两个矩阵传递给 DataFrame 构造函数。
DataFrame 的可能构造函数可以在文档 here 中找到。看起来最接近您想要的东西的可能是
DataFrame(columns::AbstractVecOrMat,names::Union{AbstractVector,Symbol};
makeunique::Bool=false,copycols::Bool=true)
适应您的用例（我在这里创建了一个随机 P 和一个简单的向量 H，其中列名当然我没有您的数据）：
julia> P = Any[rand() for i ∈ 1:3,j ∈ 1:3]
3×3 Matrix{Any}:
0.0413352 0.41672 0.266163
0.487072 0.308392 0.810582
0.470833 0.459017 0.165082
julia> H = string.('a':'c')
3-element Vector{String}:
"a"
"b"
"c"
julia> DataFrame(P,H)
3×3 DataFrame
Row │ a b c
│ Any Any Any
─────┼───────────────────────────────
1 │ 0.0413352 0.41672 0.266163
2 │ 0.487072 0.308392 0.810582
3 │ 0.470833 0.459017 0.165082
编辑：我还应该推荐只使用优秀的 CSV 包 - 正如 Bogumil 在评论中指出的那样，您面临的问题是 readdlm 将标题放入矩阵中。使用 CSV，您本可以做到：
using CSV,DataFrames
df = CSV.read("programminglanguages.csv",DataFrame)