Question

I have a file that I’m reading in and splitting and pushing into a dictionary. I keep getting an error and I think its because the street addresses contain a comma (,).

Here is my file contents:

axe99:315 W. 115th Street, Apt. 11B:New York:NY:10027
jab44:23 Rivington Street, Apt. 3R:New York:NY:10002
ap172:19 Boxer Rd.:New York:NY:10005
jb23:115 Karas Dr.:Jersey City:NJ:07127
jb29:119 Xylon Dr.:Jersey City:NJ:07127
ak9:234 Main Street:Philadelphia:PA:08990

Here is my code:

f2data = open('ex1.txt')
for line in f2data:
    print line.strip().split(':')
    city_dict = dict(item.split(':') for item in line.strip('\n').split(','))
    print city_dict

It keeps throwing this error:

['jk43', '23 Marfield Lane', 'Plainview', 'NY', '10023']

city_dict = dict(item.split(':') for item in line.strip('\n').split(','))
ValueError: dictionary update sequence element #0 has length 5; 2 is required

---

I’m new to Python and really have no idea what this error means, any thoughts greatly appreciated!

Answer 1

You are getting the error because you are trying to push a list with 5 items into a dictionary constructor when it only takes two items (in the dict constructor python thinks you are using):

here is a list of possible constructors

dict(one=1, two=2)
dict({'one': 1, 'two': 2})
dict(zip(('one', 'two'), (1, 2)))
dict([['two', 2], ['one', 1]])

taken from python docs

you will need to split your string differently or find a better way of formatting your data.
If you are reading from a csv file, refer to Michael Hoffman’s answer, which is the correct way to read from a csv.

If not, please specify what you are doing and why.

---

EDIT: Goal added, answer updated

for input:

axe99:315 W. 115th Street, Apt. 11B:New York:NY:10027
jab44:23 Rivington Street, Apt. 3R:New York:NY:10002
ap172:19 Boxer Rd.:New York:NY:10005
jb23:115 Karas Dr.:Jersey City:NJ:07127
jb29:119 Xylon Dr.:Jersey City:NJ:07127
ak9:234 Main Street:Philadelphia:PA:08990

the code:

city_dict =  {}
for line in open('ex1.txt'):
    if item.split(':')[3] in city_dict:
        city_dict[item.split(':')[3]] += 1
    else:
        city_dict[item.split(':')[3]] = 1

print (city_dict)

will output what you desire:

{'NY': 3, 'NJ': 2, 'PA': 1}