How to create csv file with dictionary key containing string as well dictionary key containing list?

Question

name = {} 

name["one"] = "onestring"
name["two"] = "twostring"
name["three"] = [1, 2, 3, 4]
name["four"] = ["string", "hello"]

Expected output should be like

one            two           three      four

onestring    twostring        1         string
                              2         hello
                              3
                              4

how to create a csv file with above format? Dictionary values has some normal string values and some has list values. How to create a csv with above format??

Do you have an error while creating a CSV? Maybe this can help:https://stackoverflow.com/questions/2084069/create-a-csv-file-with-values-from-a-python-list — AlexisG, Oct 06 '20 at 15:15
Expected output should be like one two three four onestring twostring 1 string 2 hello 3 4 — Sunny Reddy, Oct 06 '20 at 15:43
I think this [post](https://stackoverflow.com/questions/50144570/how-do-i-convert-a-dictionary-with-unequal-list-as-value-to-csv) answers your question. — Anurag Reddy, Oct 06 '20 at 16:00
Does this answer your question? [How do i convert a dictionary with unequal list as value to csv](https://stackoverflow.com/questions/50144570/how-do-i-convert-a-dictionary-with-unequal-list-as-value-to-csv) — Anurag Reddy, Oct 06 '20 at 16:00

Rivers · Answer 1 · 2020-10-06T17:12:24.857

You can do this :

import csv

name = {'one': 'onestring', 'two': 'twostring', 'three': [1, 2, 3, 4], 'four': ['string', 'hello']}

# Be sure types are str or list only
assert(all(type(x) in (str, list) for x in name.values()))

csv_filename = "names.csv"

# Get length of the biggest list
max_length = 0
for key in name:
    value = name[key]
    if type(value) is list:
        list_length = len(value)
        if list_length > max_length:
            max_length = list_length


# Replace strings and lists by only lists, of equal length
equal_lengths_dict = dict()
for key in name:
    value = name[key]
    if type(value) is str:
        replacement_list = [""] * max_length
        replacement_list[0] = value
        equal_lengths_dict[key] = replacement_list
    elif type(value) is list:
        value_length = len(value)
        if value_length < max_length:
            number_empty_strings_to_add = max_length - value_length
            empty_strings_to_add = [""] * number_empty_strings_to_add
            replacement_list = value + empty_strings_to_add
            equal_lengths_dict[key] = replacement_list
        elif value_length == max_length:
            equal_lengths_dict[key] = value
        else:
            print("error")
    else:
        print("error")


# Get field names (header row of csv)
fieldnames = list(name.keys())

# Get values that will be on the same rows
csv_rows = list()
# Csv header
csv_rows.append(fieldnames)
# Other rows
list_of_values = equal_lengths_dict.values()
for index in range(max_length):
        one_row = list()
        for value in list_of_values:
            one_row.append(value[index])
        csv_rows.append(one_row)


with open(csv_filename, "w", newline="") as f:
    writer = csv.writer(f, delimiter="\t")
    writer.writerows(csv_rows)

You will have to add some checkings and tests.

Perhaps you could rename the title of your question with someting like this : "Writing a dictionary to csv file with key/value pairs representing columns and with values of unequal length (strings and lists of variable lengths)".

Yes it does, the output of this code is what you wrote as the expected output. Could you provide more information than "No, it's not working " so I could help you ? — Rivers, Oct 06 '20 at 17:17
The good thing about continuing on stackoverflow is that it could help others. — Rivers, Oct 06 '20 at 17:23
the output of your code is onetwothreefour onestringtwostring1string 2hello 3 4 — Sunny Reddy, Oct 06 '20 at 17:33
Try to read what Pranav Hosangadi said in his comment. And if you want, post an expected output as comma separated csv in order to be clearer. — Rivers, Oct 06 '20 at 17:40

score 0 · Accepted Answer · answered Oct 06 '20 at 17:47

A short solution (mostly from here Creating dataframe from a dictionary where entries have different lengths (duplicate?)):

import pandas as pd

name = {}

name["one"] = "onestring"
name["two"] = "twostring"
name["three"] = [1, 2, 3, 4]
name["four"] = ["string", "hello"]

df = pd.DataFrame(dict([(k, pd.Series(v)) for k, v in name.items() ]))

df.to_csv("tmp.csv")

print(df)

output:

         one        two  three    four
0  onestring  twostring      1  string
1        NaN        NaN      2   hello
2        NaN        NaN      3     NaN
3        NaN        NaN      4     NaN

Yes this is working and another thing is we can do this pd.DataFrame.from_dict(name) and replace the duplicates with null values — Sunny Reddy, Oct 06 '20 at 18:01

How to create csv file with dictionary key containing string as well dictionary key containing list?

2 Answers2