Read value in Python dict and checks if keys exists.

dict_read_value.py

def dict_read_value(src, path, default=None):                                  
    value = src                                                                

    keys = path.split('.')                                                     
    for key in keys:                                                           
        if isinstance(value, dict) and key in value:                                                       
            value = value[key]                                             
        else:                                                                  
            return default                                                     

    return value                                                               

# test
d = {'x': {'y': {'z': 1}}}                                                     

assert dict_read_value(d, 'x.y.z') == 1                                        
assert dict_read_value(d, 'x.x', -1) == -1                                     
assert dict_read_value(d, 'a.b.c', 0) == 0 

neni potreba pouzivat get() kdyz vis, ze tam ten klic je, pro genericke pripady (tebe se asi netyka) by mohlo byt fajn overit ze value je dict predtim nez do nej pristoupim (radek 6)

jinak ja to resim podobne (byt to mam trochu komplikovanejsi): https://github.com/elasticsearch/elasticsearch-py/blob/master/test_elasticsearch/test_server/test_common.py#L70-L81 pro testy ala https://github.com/elasticsearch/elasticsearch/blob/master/rest-api-spec/test/update/10_doc.yaml#L39

To dava zmysel, zmenil som to ...

neni potreba pouzivat get() kdyz vis, ze tam ten klic je, pro genericke pripady (tebe se asi netyka) by mohlo byt fajn overit ze value je dict predtim nez do nej pristoupim (radek 6)

jen detail - na kontrolu typu nepouzivej porovnani ale radsi isinstance

Zmenil som type(value) == dict -> isinstance(value, dict).

Tu je vysvetlene preco je lepsie pouzit isinstance: http://stackoverflow.com/questions/1549801/differences-between-isinstance-and-type-in-python .