Question

I’ve got a question concerning the csv-module in python. I just can’t seem to write a list of dictionaries to a csv file. It would be fantastic if you could help me spot the mistake in here.

I get a TypeError: sequence item 0: expected str instance, dict found

f = open("datadump.csv", 'wt')
try:
    fieldnames = ['type', 'name', 'contact', 'address', 'tel', 'web', 'infos']
    writer = csv.DictWriter(f, fieldnames=fieldnames, delimiter=';', extrasaction='raise')
    writer.writerow(dict((fn,fn) for fn in fieldnames))
    for entry in listd:
        writer.writerow(entry)
finally:
    f.close()

listd is a list of dictionary objects, a typical one of which looks like this:

{'web': '', 'tel': 'Tel.: [phone]', 'name': ' Kinderkrippe Doppelchnopf', 'contact': '', 'address': 'Rütistrasse 37d, 8134 Adliswil', 'infos': '', 'type': 'kita'}

Answer 1

Your code basically unmodified works for me. I think maybe you have something strange with listd. Try the full code below.

import csv

fieldnames = ['type', 'name', 'contact', 'address', 'tel', 'web', 'infos']
data_item = {'web': '', 'tel': 'Tel.: [phone]', 'name': ' Kinderkrippe Doppelchnopf', 'contact': '', 'address': 'Rtistrasse 37d, 8134 Adliswil', 'infos': '', 'type': 'kita'}
listd = [data_item]*3
f = open("datadump.csv", 'wt')
writer = csv.DictWriter(f, fieldnames=fieldnames, delimiter=';', extrasaction='raise')
try:
    writer.writerow({fn:fn for fn in fieldnames})
    for entry in listd:
        writer.writerow(entry)
finally:
    f.close()