# String operation **URL:** \ **Category:** New to Julia\ **Tags:** question, strings\ **Created:** [February 13, 2024, 10:14am UTC](https://discourse.julialang.org/t/string-operation/110140 "2024-02-13T10:14:51Z")\ **Posts on this page:** 8\ **Page:** 1

**Author:** ![madsnesse](https://avatars.discourse-cdn.com/v4/letter/m/59ef9b/32.png) [@madsnesse](https://discourse.julialang.org/u/madsnesse)\ **Post date:** [February 13, 2024, 10:14am UTC](https://discourse.julialang.org/t/string-operation/110140/1 "2024-02-13T10:14:52Z")

what does this do in julia? it does not give any ParseError, and when executed in REPL it just displays the name of the variable (a) ```julia a = "abc" "aa" a ``` OUTPUT: ```julia julia> "aa" a a ``` If I change the order like this it gives ParseError: ```julia a = "abc" a "aa" ``` and doing something similar with integers gives ParseError: ```julia b = 123 12 b ``` ---

**Author:** ![abraemer](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/abraemer/32/51403_2.png) [@abraemer](https://discourse.julialang.org/u/abraemer)\ **Post date:** [February 13, 2024, 10:20am UTC](https://discourse.julialang.org/t/string-operation/110140/2 "2024-02-13T10:20:28Z")

Welcome to the discourse! Well that indeed looks very odd and had me stumped for moment 😅 What happens is that this is the syntax for adding documentation to a symbol! So if you write: ```julia-repl julia> "My string" a a ``` Then this string is used as documentation for the symbol `a`. You can see for example that it appears in the help prompt: ```julia-repl help?> a search: a as any all abs ans Any axes atan asin asec any! all! acsc acot acos abs2 atanh atand asinh asind asech asecd ascii angle acsch acscd acoth acotd acosh acosd Array ARGS atomic My string ``` ---

**Author:** ![madsnesse](https://avatars.discourse-cdn.com/v4/letter/m/59ef9b/32.png) [@madsnesse](https://discourse.julialang.org/u/madsnesse)\ **Post date:** [February 13, 2024, 10:27am UTC](https://discourse.julialang.org/t/string-operation/110140/3 "2024-02-13T10:27:41Z")

Ahhh, thanks! ---

**Author:** ![Palli](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/palli/32/3380_2.png) [@Palli](https://discourse.julialang.org/u/Palli)\ **Post date:** [February 13, 2024, 10:47am UTC](https://discourse.julialang.org/t/string-operation/110140/4 "2024-02-13T10:47:43Z")

It’s meant for functions/methods (which ARE also symbols?!), if not arbitrary symbols. I’m not sure you would ever use this for variables, or rely on that possibility, should it then error? EDIT: I recalled `pi` is a constant (irrational) “variable”, so at least used for help strings of such. Out of curiosity, does Julia have any (non-constant) global variables? I was trying to think of some, and could only think of a seed for `rand`, and rand is global, maybe the seed, though it’s strictly thread-local (at least with the new rand). Anyway this at least needs to be a possibility, and I suppose for package code too, even though globals are in general bad, with few exceptions. The REPL could still warn about it in case wrong… ---

**Author:** ![abraemer](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/abraemer/32/51403_2.png) [@abraemer](https://discourse.julialang.org/u/abraemer)\ **Post date:** [February 13, 2024, 11:24am UTC](https://discourse.julialang.org/t/string-operation/110140/5 "2024-02-13T11:24:18Z")

> [@Palli](#): > > It’s meant for functions/methods (which ARE also symbols?!), if not arbitrary symbols. The [manual talks](https://docs.julialang.org/en/v1/manual/documentation/#Syntax-Guide) about adding documentation to many things and among them are also [global variables](https://docs.julialang.org/en/v1/manual/documentation/#Global-Variables) 🙂 So I was probably not fully correct above. The documentation is not really attached to the symbol (which I think is how Common Lisp does it) but to the global variable of that name. ---

**Author:** ![sijo](https://avatars.discourse-cdn.com/v4/letter/s/da6949/32.png) [@sijo](https://discourse.julialang.org/u/sijo)\ **Post date:** [February 13, 2024, 12:28pm UTC](https://discourse.julialang.org/t/string-operation/110140/6 "2024-02-13T12:28:02Z")

The terminology is a bit confusing but I’d say it’s the other way: the documentation is attached to the binding (i.e. the symbol) and not the object. So you can have different docstrings for different aliases: ```julia julia> "The type for a vector" const Vec = Vector Vec help?> Vec search: Vec vec Vector VecOrMat VecElement eigvecs BitVector DenseVector DenseVecOrMat StridedVector StridedVecOrMat AbstractVector The type for a vector julia> "The type for a Point" const Point = Vector Point help?> Vec search: Vec vec Vector VecOrMat VecElement eigvecs BitVector DenseVector DenseVecOrMat StridedVector StridedVecOrMat AbstractVector The type for a vector help?> Point search: Point pointer pointer_from_objref codepoint unsafe_pointer_to_objref typejoin position ComposedFunction process_running The type for a Point ``` or for two bindings to the same array object: ```julia julia> "array A" A = [1, 2, 3] A julia> "array B" B = A B help?> A search: A as Any any all abs ARGS ans axes atan asin asec any! all! acsc acot acos abs2 Array atanh atand asinh asind asech asecd ascii angle array A help?> B search: B Bool big BLAS Base bind break begin bswap BitSet BigInt BitArray BigFloat binomial basename Broadcast BitVector BitMatrix bytes2hex array B ``` ---

**Author:** ![abraemer](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/abraemer/32/51403_2.png) [@abraemer](https://discourse.julialang.org/u/abraemer)\ **Post date:** [February 13, 2024, 12:40pm UTC](https://discourse.julialang.org/t/string-operation/110140/7 "2024-02-13T12:40:02Z")

> [@sijo](#): > > the documentation is attached to the binding (i.e. the symbol) and not the object. This seems not to seem to be true for functions: ```julia-repl julia> "foo docstring" function foo(x) return x end foo julia> const f = foo foo (generic function with 1 method) julia> "another alias for foo" const f2 = foo f2 help?> foo search: foo floor fourthroot pointer_from_objref OverflowError RoundFromZero unsafe_copyto! functionloc StackOverflowError @functionloc OutOfMemoryError UndefKeywordError foo docstring help?> f search: f fd for fma fld foo fld1 fill fdio frexp foldr foldl flush floor float first fill! fetch fldmod filter falses finally foreach fldmod1 findmin findmax findall filter! function foo docstring help?> f2 search: Float32 f2 Inf32 ComplexF32 another alias for foo ``` So function appear to know about “their” docstrings. Which makes sense I guess, since we can document methods individually. So the documentation needs to be attached to the actual function objects and not their names. But apart from that it is most likely the binding/name/symbol that is documented and not the object underneath. ---

**Author:** ![mnemnion](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/mnemnion/32/206596_2.png) [@mnemnion](https://discourse.julialang.org/u/mnemnion)\ **Post date:** [February 13, 2024, 5:32pm UTC](https://discourse.julialang.org/t/string-operation/110140/8 "2024-02-13T17:32:51Z")

> [@sijo](#): > > The terminology is a bit confusing but I’d say it’s the other way: the documentation is attached to the binding (i.e. the symbol) and not the object. So you can have different docstrings for different aliases: This isn’t entirely accurate, in that if you make an alias for a value (such as a function) but don’t attach documentation, Julia will still find the original documentation. If you document the alias, it won’t. ```julia julia> "a foo function" foo(a, b, c) = a * b * c foo help?> foo search: foo floor fourthroot pointer_from_objref OverflowError RoundFromZero unsafe_copyto! functionloc StackOverflowError @functionloc a foo function julia> bar = foo foo (generic function with 1 method) help?> bar search: bar baremodule SubArray GlobalRef clipboard BitArray backtrace BasicREPL BitMatrix catch_backtrace AbstractREPL AbstractRange AbstractArray a foo function julia> "a bar function" bar bar help?> bar search: bar baremodule SubArray GlobalRef clipboard BitArray backtrace BasicREPL BitMatrix catch_backtrace AbstractREPL AbstractRange AbstractArray a bar function ``` Note that this isn’t function-specific behavior, it generalizes: ```julia julia> "my struct" struct MyStruct end MyStruct help?> MyStruct search: MyStruct my struct julia> AnAlias = MyStruct MyStruct help?> AnAlias search: AnAlias rationalize CanonicalIndexError my struct julia> "with an alias" AnAlias AnAlias help?> AnAlias search: AnAlias rationalize CanonicalIndexError with an alias ```