How to concatenate strings in django templates

Question

I want to concatenate a string in a Django template tag  like      extend shop shop name base html      Here shop name is my variable and I want to concatenate this with rest of path   Suppose I have shop name example com and I want result to extend shop example com base html

User · Answer

You can t do variable manipulation in django templates   You have two options  either write your own template tag or do this in view

User · Answer

You do not need to write a custom tag  Just evaluate the vars next to each other   quot    shop name      other path var   quot

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error s answer is fundamentally right  you should be using a template tag for this  However  I prefer a slightly more generic template tag that I can use to perform any kind of operations similar to this   from django import template register   template Library      register tag name  captureas   def do captureas parser  token               Capture content for re-use throughout a template      particularly handy for use within social meta fields      that are virtually identical               try          tag name  args   token contents split None  1      except ValueError          raise template TemplateSyntaxError   captureas  node requires a variable name        nodelist   parser parse   endcaptureas         parser delete first token       return CaptureasNode nodelist  args    class CaptureasNode template Node       def   init   self  nodelist  varname           self nodelist   nodelist         self varname   varname      def render self  context           output   self nodelist render context          context self varname    output         return      and then you can use it like this in your template      captureas template   shop    shop name    base html   endcaptureas       include template      As the comment mentions  this template tag is particularly useful for information that is repeatable throughout a template but requires logic and other things that will bung up your templates  or in instances where you want to re-use data passed between templates through blocks       captureas meta title      spaceless      block meta title           if self title      self title      endif           endblock      endspaceless    - DEFAULT WEBSITE NAME    endcaptureas      and then    lt title gt    meta title    lt  title gt   lt meta property  og title  content     meta title       gt   lt meta itemprop  name  content     meta title     gt   lt meta name  twitter title  content     meta title     gt    Credit for the captureas tag is due here  https   www djangosnippets org snippets 545

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From the docs   This tag can be used in two ways       extends  base html      with quotes  uses the literal value  base html  as the name of the parent template to extend     extends variable    uses the value of variable  If the variable evaluates to a string  Django will use that string as the name of the parent template  If the variable evaluates to a Template object  Django will use that object as the parent template    So seems like you can t use a filter to manipulate the argument  In the calling view you have to either instantiate the ancestor template or create an string variable with the correct path and pass it with the context

User · Answer

Have a look at the add filter   Edit  You can chain filters  so you could do  shop   add shop name add   base html   But that won t work because it is up to the template tag to evaluate filters in arguments  and extends doesn t   I guess you can t do this within templates

User · Answer

Don t use add for strings  you should define a custom tag like this   Create a file    lt appname gt  templatetags  lt appname gt  extras py from django import template  register   template Library     register filter def addstr arg1  arg2        quot  quot  quot concatenate arg1  amp  arg2 quot  quot  quot      return str arg1    str arg2   and then use it as  Steven says    load  lt appname gt  extras        with  quot shop  quot  addstr shop name addstr  quot  base html quot  as template           include template       endwith     Reason for avoiding add  According to the docs  This filter will first try to coerce both values to integers    Strings that can be coerced to integers will be summed  not concatenated     If both variables happen to be integers  the result would be unexpected

User · Answer

I have changed the folder hierarchy       shop shop name base html To  shop name shop base html   and then below would work      extends shop name add   shop base html       Now its able to extend the base html page

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Refer to Concatenating Strings in Django Templates    For earlier versions of Django       Mary had a little  stringformat  s lamb            Mary had a little lamb      Else       Mary had a little  add   lamb            Mary had a little lamb

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In my project I did it like this   register simple tag   def format string string  str   args  str  - gt  str       quot  quot  quot      Adds  args  values to  string      String format  string    quot Drew  s dad s  s dead  quot      Function call in template     format string string  quot Dodd s quot   quot dog s quot         Result   quot Drew Dodd s dad s dog s dead  quot       quot  quot  quot      return string   args  Here  the string you want concatenate and the args can come from the view  for example  In template and using your case     format string  shop  s base html  shop name as template       include template     The nice part is that format string can be reused for any type of string formatting in templates

User · Answer

Use with      with  shop   add shop name add   base html  as template       include template       endwith

User · Answer

extends has no facility for this  Either put the entire template path in a context variable and use that  or copy the exist template tag and modify it appropriately

User · Answer

And multiple concatenation   from django import template register   template Library      register simple tag def concat all  args          concatenate all args        return    join map str  args     And in Template      concat all  x   y  another var as string result    concatenated string     string result

User · Answer

I found working with the    with    tag to be quite a hassle  Instead I created the following template tag  which should work on strings and integers   from django import template  register   template Library      register filter def concat string value 1  value 2       return str value 1    str value 2    Then load the template tag in your template at the top using the following      load concat string      You can then use it the following way    lt a href     SOME DETAIL URL concat string object pk     target   blank  gt 123 lt  a gt    I personally found this to be a lot cleaner to work with

[django] How to concatenate strings in django templates?

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