'ValueError: too many values to unpack (expected 10)'

Question

I am working on a self-learning project on AIS ship tracking, and the following line of code:

hi_boat1,hi_boat2,hi_boat3,hi_boat4,hi_boat5,hi_boat6,hi_boat7,hi_boat8,hi_boat9,hi_boat10 = [x for _, x in hi_eez.groupby(hi_eez['mmsi'])]

is giving me the following error:

ValueError: too many values to unpack (expected 10)

What should I do?

Please provide your code (or an example that produces the same error). — Crazy Engineer, Sep 02 '22 at 11:31
At first glance i'd guess that your list comprehension returns a list of length > 10. But yeah like @CrazyEngineer said a full example would help — Charles G, Sep 02 '22 at 11:37
Please provide enough code so others can better understand or reproduce the problem. — Community, Sep 02 '22 at 11:37

tom · Accepted Answer · 2022-09-02T11:54:53.277

the error says that the code on the right-hand side of the expression should return a list with 10 objects as you use ten variables on the left hand side for unpacking that list.

see "Too many values to unpack" Exception

e.g. a,b,c,d,e,f,g = [x for x in range(7)] works while a,b,c,d,e,f,g = [x for x in range(8)] throws ValueError: too many values to unpack (expected 7)

you should state what you are trying to achieve and maybe add the desired output. so, you could for example assign that list to a variable and then further process it.

my_list = [x for _, x in hi_eez.groupby(hi_eez['mmsi'])]

for elem in my_list:
    print(elem)

'ValueError: too many values to unpack (expected 10)'

1 Answers1