Django template how to look up a dictionary value with a variable

Question

mydict     key1   value1    key2   value2     The regular way to lookup a dictionary value in a Django template is    mydict key1         mydict key2     What if the key is a loop variable  ie      for item in list      where item has an attribute NAME      mydict item NAME      I want to look up mydict item NAME     endfor      mydict item NAME fails  How to fix this

User · Answer

I had a similar situation  However I used a different solution   In my model I create a property that does the dictionary lookup  In the template I then use the property   In my model  -   property def state  self           Return the text of the state rather than an integer         return self STATE self state    In my template  -  The state is     item state

User · Answer

Environment  Django 2 2   Example code          from django template defaulttags import register       register filter name  lookup       def lookup value  arg           return value get arg     I put this code in a file named template filters py in my project folder named portfoliomgr   No matter where you put your filter code  make sure you have   init   py in that folder Add that file to libraries section in templates section in your projectfolder settings py file  For me  it is portfoliomgr settings py         TEMPLATES                            BACKEND    django template backends django DjangoTemplates                DIRS    os path join BASE DIR   templates                  APP DIRS   True               OPTIONS                      context processors                          django template context processors debug                        django template context processors request                        django contrib auth context processors auth                        django contrib messages context processors messages                                       libraries                         template filters    portfoliomgr template filters                                                         In your html code load the library      load template filters

User · Answer

Write a custom template filter  from django template defaulttags import register      register filter def get item dictionary  key       return dictionary get key    I use  get so that if the key is absent  it returns none  If you do dictionary key  it will raise a KeyError then   usage     mydict get item item NAME

User · Answer

env  django 2 1 7  view    dict objs query obj id      obj   query obj   tag   str tag  return render request   obj html     dict objs   dict objs     template       for obj id dict obj in dict objs items     lt td gt    dict obj obj obj name    lt  td gt   lt td style  display none  gt    obj id    lt  td gt   lt td gt    forloop counter    lt  td gt   lt td gt    dict obj obj update timestamp date  Y-m-d H i s    lt  td gt

User · Answer

You can t by default  The dot is the separator   trigger for attribute lookup   key lookup   slice      Dots have a special meaning in template rendering  A dot in a variable   name signifies a lookup  Specifically  when the template system   encounters a dot in a variable name  it tries the following lookups    in this order          Dictionary lookup  Example  foo  bar      Attribute lookup  Example  foo bar    List-index lookup  Example  foo bar       But you can make a filter which lets you pass in an argument   https   docs djangoproject com en dev howto custom-template-tags  writing-custom-template-filters   register filter name  lookup   def lookup value  arg       return value arg      mydict lookup item name

User · Answer

For me creating a python file named template filters py in my App with below content did the job    coding utf-8 from django template base import Library  register   Library      register filter def get item dictionary  key       return dictionary get key    usage is like what culebr  n said       mydict get item item NAME

User · Answer

Fetch both the key and the value from the dictionary in the loop      for key  value in mydict items           value       endfor      I find this easier to read and it avoids the need for special coding  I usually need the key and the value inside the loop anyway

User · Answer

Since I can t comment  let me do this in the form of an answer  to build on culebr  n s answer or Yuji  Tomita  Tomita s answer  the dictionary passed into the function is in the form of a string  so perhaps use ast literal eval to convert the string to a dictionary first  like in this example  With this edit  the code should look like this    code for custom template tag  register filter name  lookup   def lookup value  arg       value dict   ast literal eval value      return value dict get arg    lt  --template tag  in the template -- gt     mydict lookup item name

[python] Django template how to look up a dictionary value with a variable

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