Unpacking list in Python - ValueError: not enough values to unpack-CodePudding

I test my script just printing return value of .split:

for f in os.listdir():
    f_name, f_ext = os.path.splitext(f)
    print(f_name.split('-'))

and it shows me what I'd like to see - lists with 3 strings in each.

['Earth ', ' Our Solar System ', ' #4']
['Saturn ', ' Our Solar System ', ' #7']
['The Sun ', ' Our Solar System ', ' #1']

However, when I'm trying to store it in 3 different variables:

for f in os.listdir():
    f_name, f_ext = os.path.splitext(f)
    f_title, f_course, f_num = f_name.split(' - ')

it gives me an error:

f_title, f_course, f_num = f_name.split('-')
    ^^^^^^^^^^^^^^^^^^^^^^^^
ValueError: not enough values to unpack (expected 3, got 1)

I'd appreciate any help on this! Thanks!

CodePudding user response：

What you are experiencing is the diffrence between unpacking three items and a list. What you are getting from f.split is a single item only which is a list of the 'words'

f_name = 'a-b-c'
f_name.split("-") -> [a,b,c] #But a list is a single entity

So consider :

[title,course,num]= f_name.split("-")

However this is not a very good way to do it. What happens if split returns 4 words in a list ? Although this solves your problem, I highly doubt you should be doing it in this way.

CodePudding user response：

It seems like there are unwanted spaces around the hyphen f_name.split(' - '). Remove them:

for f in os.listdir():
    f_name, f_ext = os.path.splitext(f)
    f_title, f_course, f_num = f_name.split('-')