# Parsing DateTimes in Julia 0.6

**URL:** <https://discourse.julialang.org/t/parsing-datetimes-in-julia-0-6/4397>\
**Category:** General Usage\
**Created:** [June 21, 2017, 8:45pm UTC](https://discourse.julialang.org/t/parsing-datetimes-in-julia-0-6/4397 "2017-06-21T20:45:55Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![evanfields](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/evanfields/32/1744_2.png) [@evanfields](https://discourse.julialang.org/u/evanfields)\
**Post date:** [June 21, 2017, 8:45pm UTC](https://discourse.julialang.org/t/parsing-datetimes-in-julia-0-6/4397/1 "2017-06-21T20:45:55Z")

</div>

Short version: what’s the Julia 0.6 way to parse a DateTime from a String when the String has extra non-date info at the end, e.g. `"2017-6-21 other text here"`?

Since upgrading to Julia 0.6, I’ve run into trouble with parsing DateTimes from strings. The strings look like `07-DEC-13 03.00.00.000000000 PM`. In Julia 0.5.2, I can parse these fine:

```julia
julia> s = "07-DEC-13 03.00.00.000000000 PM";

julia> tf = Dates.DateFormat("d-u-y H.M.S.");

julia> DateTime(s, tf)
0013-12-07T03:00:00

```

But in Julia 0.6, an error is thrown because the string has extra characters following the specified date format:

```julia
julia> s = "07-DEC-13 03.00.00.000000000 PM";

julia> tf = Dates.DateFormat("d-u-y H.M.S.");

julia> DateTime(s, tf)
ERROR: ArgumentError: Found extra characters at the end of date time string
Stacktrace:
 [1] macro expansion at .\dates\parse.jl:103 [inlined]
 [2] tryparsenext_core(::String, ::Int64, ::Int64, ::DateFormat{Symbol("d-u-y H.M.S."),Tuple{Base.Dates.DatePart{'d'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'u'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'y'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'H'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'M'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'S'},Base.Dates.Delim{Char,1}}}, ::Bool) at .\dates\parse.jl:39
 [3] macro expansion at .\dates\parse.jl:153 [inlined]
 [4] tryparsenext_internal(::Type{DateTime}, ::String, ::Int64, ::Int64, ::DateFormat{Symbol("d-u-y H.M.S."),Tuple{Base.Dates.DatePart{'d'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'u'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'y'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'H'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'M'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'S'},Base.Dates.Delim{Char,1}}}, ::Bool) at .\dates\parse.jl:129
 [5] parse(::Type{DateTime}, ::String, ::DateFormat{Symbol("d-u-y H.M.S."),Tuple{Base.Dates.DatePart{'d'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'u'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'y'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'H'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'M'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'S'},Base.Dates.Delim{Char,1}}}) at .\dates\parse.jl:270
 [6] DateTime(::String, ::DateFormat{Symbol("d-u-y H.M.S."),Tuple{Base.Dates.DatePart{'d'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'u'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'y'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'H'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'M'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'S'},Base.Dates.Delim{Char,1}}}) at .\dates\io.jl:422

```

Okay, so in this case I can just manually split each input string at the last `.`, parse the first part as a DateTime, check whether the second part has `AM` or `PM` in it, etc., but this feels suspiciously close to just parsing manually, which presumably is not the intended way to do this, especially given all the parsing mechanisms that do exist.

So I check the release notes which include the following: “Parsing string dates from a Dates.DateFormat object has been deprecated as part of a larger effort toward faster, more extensible date parsing (#20952).” But the [documentation](https://docs.julialang.org/en/stable/manual/dates/#Constructors-1) still suggests using a `DateFormat` object to parse the string, and the only deprecation I see in PR [20952](https://github.com/JuliaLang/julia/pull/20952) is for `Dates.parse`.

And in fact, `Dates.parse` does something quite unintuitive (to me) - not the parsing I’d expect:

```julia
julia> Dates.parse("2017-6-21", dateformat"y-m-d")
WARNING: `Dates.parse(x::AbstractString, df::DateFormat)` is deprecated, use `sort!(filter!(el -> isa(el, Dates.Period), Dates.parse_components(x, df), rev=true, lt=Dates.periodisless)` instead.
Stacktrace:
 [1] depwarn(::String, ::Symbol) at .\deprecated.jl:70
 [2] parse(::String, ::DateFormat{Symbol("y-m-d"),Tuple{Base.Dates.DatePart{'y'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'m'},Base.Dates.Delim{Char,1},Base.Dates.DatePart{'d'}}}) at .\deprecated.jl:1310
 [3] eval(::Module, ::Any) at .\boot.jl:235
 [4] eval_user_input(::Any, ::Base.REPL.REPLBackend) at .\REPL.jl:66
 [5] macro expansion at .\REPL.jl:97 [inlined]
 [6] (::Base.REPL.##1#2{Base.REPL.REPLBackend})() at .\event.jl:73
while loading no file, in expression starting on line 0
3-element Array{Any,1}:
 2017 years
 6 months
 21 days

```

i.e., `Dates.parse` is not parsing the string as a date according to the DateFormat anyway, and I have a very high prior that the suggested `sort!(filter!(...` is not intended to be the general purpose way to parse a DateTime from a string.

So two questions:

1. Is it a bug that the constructor `DateTime(String, DateFormat)` now fails on trailing characters not part of the specified DateFormat, and if not a bug, how should such strings generally be dealt with?
2. What is the proper way to parse a DateTime, and is it a documentation error that the update notes make a cryptic reference to using DateFormat being deprecated while the docs continue to suggest it?