How to combine multiple try-except blocks?

Question

I have a bunch of statements I want to use try, except on. Yes bad practise.

There must be a more pythonic way to write the following?

try:
    E1=clean_html.find("span",{"class":"range-a"}).text
except AttributeError:
    E1=None

try:
    E2=clean_html.find("span",{"class":"range-b"}).text 
except AttributeError:
    E2=None

try:
    E3=clean_html.find("span",{"class":"range-c"}).text 
except AttributeError:
    E3=None

try:
    E4=clean_html.find("div",{"class":"Description"}).get_text(separator=" ").strip()
except AttributeError:
    E4=None

Because this code works fine for me, but it looks unefficient.

Answer 1

You can assign a default to the variables and then do the work. Since you want the default to be the immutable None , you can

E1 = E2 = E3 = E4 = None

try:
    E1=clean_html.find("span",{"class":"range-a"}).text
    E2=clean_html.find("span",{"class":"range-b"}).text 
    E3=clean_html.find("span",{"class":"range-c"}).text 
    E4=clean_html.find("div",{"class":"Description"}).get_text(separator=" ").strip()
except AttributeError:
    pass

The best way to handle exceptions depends on more context than we have here, but generally you want to write larger blocks that stay in a sane state on any "exceptional" operation.

Since exceptions take some processing power to setup and may be visually untidy, testing (especially when wrapped in its own function) can be a better way to go.

def get_elem_text(elem, default=None):
    if elem:
        return elem.text
    else:
        return default

E1=get_elem_text(clean_html.find("span",{"class":"range-a"}))
E2=get_elem_text(clean_html.find("span",{"class":"range-b"})) 
E3=get_elem_text(clean_html.find("span",{"class":"range-c"})) 
# I don't know what "get_text" is so can't abstract it
#E4=get_elem_text(clean_html.find("div",{"class":"Description"}), default="")).strip()

Answer 2

You can write a function that handles the try and except. You can pass the post_processing as a lambda if you want the function to handle the problem of None throwing errors when calling methods on it

def get_clean_text(tag, class_name, post_processor):
    try:
        return post_processor(clean_html.find(tag,{"class": class_name}))
    except AttributeError:
        return None

E1 = get_clean_text("span", "range-a", lambda o: o.text)
E4 = get_clean_text("div", "Description", lambda o: o.get_text(separator=" ").strip())