# Concatenation of strings not working inside a function

**URL:** <https://discourse.julialang.org/t/concatenation-of-strings-not-working-inside-a-function/22250>\
**Category:** General Usage\
**Created:** [March 23, 2019, 3:33pm UTC](https://discourse.julialang.org/t/concatenation-of-strings-not-working-inside-a-function/22250 "2019-03-23T15:33:12Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![iamsuddhasattwa](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/iamsuddhasattwa/32/7441_2.png) [@iamsuddhasattwa](https://discourse.julialang.org/u/iamsuddhasattwa)\
**Post date:** [March 23, 2019, 3:33pm UTC](https://discourse.julialang.org/t/concatenation-of-strings-not-working-inside-a-function/22250/1 "2019-03-23T15:33:12Z")

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The simple function of concatenating strings does not seem to be working. I tried this simplest of codes on v1.1.0.

> function f(name::String) :: String  
> return String(name, “\_GaussKer”);  
> end  
> julia\> s = f(“test”)  
> ERROR: MethodError: no method matching String(::String, ::String)  
> Closest candidates are:

Do you know what is happening ?

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**Author:** ![stevengj](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/stevengj/32/71_2.png) [@stevengj](https://discourse.julialang.org/u/stevengj)\
**Post date:** [March 23, 2019, 3:55pm UTC](https://discourse.julialang.org/t/concatenation-of-strings-not-working-inside-a-function/22250/2 "2019-03-23T15:55:33Z")

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For concatenation, you want `string` (or the `*` operator), not `String`.

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**Author:** ![StevenSiew](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/stevensiew/32/218393_2.png) [@StevenSiew](https://discourse.julialang.org/u/StevenSiew)\
**Post date:** [March 23, 2019, 10:15pm UTC](https://discourse.julialang.org/t/concatenation-of-strings-not-working-inside-a-function/22250/3 "2019-03-23T22:15:01Z")

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string lowercase is a function (like println)  
String uppercase is a type (like Float64)

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**Author:** ![iamsuddhasattwa](https://sea2.discourse-cdn.com/julialang/user_avatar/discourse.julialang.org/iamsuddhasattwa/32/7441_2.png) [@iamsuddhasattwa](https://discourse.julialang.org/u/iamsuddhasattwa)\
**Post date:** [March 24, 2019, 2:00am UTC](https://discourse.julialang.org/t/concatenation-of-strings-not-working-inside-a-function/22250/4 "2019-03-24T02:00:57Z")

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Thank you for the clarification. It is really helpful.