`readdlm` dictionary parsing default behavior

[jakebolewski]

julia> english = readdlm(IOBuffer(readstring("/usr/share/dict/words")),  ' ')
235886×1 Array{Any,2}:
 "A"
 "a"
 "aa"
 "aal"
 "aalii"
 "aam"
 "Aani"
 "aardvark"
 "aardwolf"
 "Aaron"
 "Aaronic"
 "Aaronical"
 "Aaronite"
 "Aaronitic"
 "Aaru"
 "Ab"
 "aba"
 "Ababdeh"
 "Ababua"
 "abac"
 "abaca"
 "abacate"
 "abacay"
 ⋮
 "zymoscope"
 "zymosimeter"
 "zymosis"
 "zymosterol"
 "zymosthenic"
 "zymotechnic"
 "zymotechnical"
 "zymotechnics"
 "zymotechny"
 "zymotic"
 "zymotically"
 "zymotize"
 "zymotoxic"
 "zymurgy"
 "Zyrenian"
 "Zyrian"
 "Zyryan"
 "zythem"
 "Zythia"
 "zythum"
 "Zyzomys"
 "Zyzzogeton"

julia> english_lower = map(lowercase, english);
ERROR: MethodError: no method matching lowercase(::Bool)
 in collect_to!(::Array{String,2}, ::Base.Generator{Array{Any,2},Base.#lowercase}, ::Int64, ::Int64) at ./array.jl:267
 in _collect(::Array{Any,2}, ::Base.Generator{Array{Any,2},Base.#lowercase}, ::Base.EltypeUnknown, ::Base.HasShape) at ./array.jl:249
 in map(::Function, ::Array{Any,2}) at ./abstractarray.jl:1131
 in eval(::Module, ::Any) at ./boot.jl:225
 in macro expansion at ./REPL.jl:92 [inlined]
 in (::Base.REPL.##1#2{Base.REPL.REPLBackend})() at ./event.jl:46

julia> Set(typeof(x) for x in english)
Set(Any[Bool,SubString{String},Float64])

julia> english_str = map(strip, split(readstring("/usr/share/dict/words")));

julia> foreach(english_str) do x
       try
       parse(Float64, x)
       println(x)
       end
       end
infinity
Nan
nan