from django import template

register = template.Library()

# Utility used like {{ dict|getval:key_name }} to return value even when using variables in dictionary key
@register.filter(name='getval')
def getval(tupdict, key_name):
    """Use this in a template as follows:
    
    To retrieve the value of a dict:
    {{ crime_rates_dict|getval:"Chicago" }} <-- will return value of crime_rates_dict["Chicago"]

    To retrieve the human-readable value from a choices tuple:
    {{ country.COUNTRIES|getval:"US" }} <-- will return "United States" in COUNTRIES = (("US", "United States"),)
    """
    value = ''
    if type(tupdict) == type(()):
        # Assume this is likely a "choices" list, and the friendly value should be returned
        try:
            value = [choice[1] for choice in tupdict if key_name in choice]
            value = value.pop()
        except:
            value = ''
    elif type(tupdict) == type({}):
        # This is a regular dictionary, and the requested value should be returned
        value = tupdict.get(key_name, '')

    return value