How to iterate over nested dictionaries in django templates

Question

I'm not sure the most efficient way to iterate over my nested dictionaries to print a matrix of the total and good values for every fruit for each date. Take for instance the two lists and dictionary below:

fruits = ['apples','oranges','bananas'] harvest_dates = ['2011-07-23','2011-07-22','2011-07-21']  harvest_data = {   'apples': {     '2011-07-23': {       'total': 100,       'good': 80},      '2011-07-22': {        'total': 97,        'good': 92},      '2011-07-21': {        'total': 90,        'good': 85}   },   'oranges': {     '2011-07-23': {       'total': 86,       'good': 82},     '2011-07-22': {       'total': 90,        'good': 75},     '2011-07-21': {       'total': 92,       'good': 92}   },   'bananas': {     '2011-07-23': {       'total': 10,       'good': 9},     '2011-07-22': {       'total': 12,        'good': 11},     '2011-07-21': {       'total': 9,       'good': 9}   } } 

I can easily do this in python:

for fruit in fruits:   for day in harvest_dates:     print "harvest: %s" % harvest_data[fruit][day]['total']     print "good crop: %s" % harvest_data[fruit][day]['good'] 

But I don't know how to access this data in django templates. I had been trying something such as:

{% for fruit in fruits %}   ...   {% for day in harvest_dates %}     ...     {{ harvest_data.fruit.day.total }}     {{ harvest_data.fruit.day.good }}     ...   {% endfor %} {% endfor %} 

But it's simply not working.

{% for fruit in fruits %}   {{ harvest_data.fruit }}  <--- this does not exist   {{ harvest_data[fruit] }}  <--- this does not work {% endfor %} 

I'm a complete amateur and I'm probably going about this all wrong, but I've Google'd quite a bit and it's not clear to me what the best approach to getting the data I want is.

Answer 1

Since you're familiar with python, the following is logically how you would want to iterate through your dictionary in a Django template:

for key,value in harvest_data.items(): ...     print key ...     for key2,value2 in value.items(): ...         print key2 ...         for key3,value3 in value2.items(): ...             print "%s:%s"%(key3,value3) 

In your template, this translates as follows:

{% for key, value in harvest_data.items %}     {{ key }} <br>     {% for key2,value2 in value.items %}         {{ key2 }} <br>         {% for key3, value3 in value2.items %}             {{ key3 }}:{{ value3 }} <br>         {% endfor %}     {% endfor %} {% endfor %} 

The Django docs actually briefly include an example of how to iterate through dictionaries when describing how the for template tag works:

https://docs.djangoproject.com/en/dev/ref/templates/builtins/#for

Answer 2

as rolling stone says thats the way to iterate over dictionaries in templates, i would only change the key, value keywords for different keywords in every iteration like this:

{% for key, value in harvest_data.items %}     {{ key }} <br>     {% for key2,value2 in value.items %}         {{ key2 }} <br>         {% for key3, value3 in value2.items %}             {{ key3 }}:{{ value3 }} <br>         {% endfor %}     {% endfor %} {% endfor %} 

just for the sake of clarity :)

And if you want to line up your values i would suggest you use another data structure where you can sort by date, for example a something like this:

{ 'oranges' : [(date1, value1), (date2,value2)] ...} 

Try to do the least possible operations in your templates, so dont do a sort or nested if's if you dont have to