How to save JSON string into CSV or TXT in Python?

Question

In Python how to save the following JSON string into CSV file?

{
'1.txt': [], 
'2.txt': [], 
'5.txt': [], 
'4.txt': ['3.txt','6.txt'],
'7.txt': ['8.txt']
}

The important thing is that I want to save only numbers of those entries that have children, i.e. for the above example the result would be:

This is what I prepared so far, but I don't know how to check for nested elements:

    x = json.loads(data)

    f = csv.writer(open("test.csv", "wb+"))

    # Write CSV Header
    f.writerow(["number"])

    for x in x:
            f.writerow([x[...]])

Your example code does not match the intended output. Your CSV declares two header fields but intended output is line-by-line. Please clarify. — dhke
– dhke, Commented Mar 9, 2015 at 11:04

Padraic Cunningham · Accepted Answer · 2015-03-09 12:00:14Z

1

Just check if the list is empty or not iterating of the items in the dict:

for k, v in d.items(): 
    if v: # will be False for any empty list
        print(k.split(".")[0])
        print([s.split(".")[0] for s in v])
7
['8']
4
['3', '6']

Depending on what output you want:

f = csv.writer(open("test.csv", "w")) 

# Write CSV Header
f.writerow(["name", "qty"])


for k, v in d.items(): # iteritems python2
    if v:
        f.writerow([k.split(".")[0]]+[s.split(".")[0] for s in v])

Which outputs:

name,qty
7,8
4,3,6

If you want all on separate lines:

with open("test.csv","w") as f:
    f.write("name\n")
    for k, v in d.items():
        if v:
            f.write("{}\n".format(k.split(".")[0]))
            f.write("\n".join([s.split(".")[0] for s in v])+"\n"

Output:

name
7
8
4
3
6

To use the csv module you would need to wrap the subelements in lists or some container:

with open("test.csv","w") as f:
    wr = csv.writer(f)
    wr.writerow(["name"])
    for k, v in d.items():
        if v:
            wr.writerow([k.split(".")[0]])
            wr.writerows([[s.split(".")[0]] for s in v])

edited Mar 9, 2015 at 12:00

answered Mar 9, 2015 at 11:17

Padraic Cunningham

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9 Comments

Klausos Klausos Over a year ago

Thanks. You are right. I just need 1 column with numbers.

Padraic Cunningham Over a year ago

@KlausosKlausos, no worries, the writerows will put on on their own line.

Klausos Klausos Over a year ago

After running your code, I received 3 columns with some strange numbers that do not coincide with my expectations. What might be the reason?

Padraic Cunningham Over a year ago

@KlausosKlausos, you know dicts have no order yes?

Klausos Klausos Over a year ago

For instance, first line in CSV file is "1, 8, 5", however it is not correct.

|

Eugene Soldatov · Accepted Answer · 2015-03-09 11:23:07Z

0

This should be working:

data = {
    '1.txt': [], 
    '2.txt': [], 
    '5.txt': [], 
    '4.txt': ['3.txt','6.txt'],
    '7.txt': ['8.txt']
}
f = csv.writer(open("test.csv", "wb+"))
f.writerow(["name", "qty"])
for key, value in data.iteritems():
    if len(value) > 0:
        f.writerow([key, len(value)])

answered Mar 9, 2015 at 11:23

Eugene Soldatov

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1 Comment

dhke Over a year ago

Side note: You can also use if not value, as bool([]) == False

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