Python 用 header 将字典写入 csv

Question

I want to write a specific python dictionary to csv with header. I have looked at other questions but none of them have the similar dictionary structure as mine:

myDic = { "a" : 1, "b" : 2, "c" : 15}

header = ["word", "count"]

with open('myFile.csv', 'w', encoding='utf-8-sig') as f:
    w = csv.DictWriter(f, header)
    w.writeheader()
    w.writerow(myDic)

What I got is only word,count in my CSV file. I am using python 3.

Answer 1

You can't use DictWriter in that way, it is designed for key=column_header and value=[row_values] .

You can instead iterate your dictionary and use csv.writerow

import csv

myDic = { "a" : 1, "b" : 2, "c" : 15}

header = ["word", "count"]

with open('myFile.csv', 'w', encoding='utf-8-sig') as f:
    w.writerow(header)
    for k, v in myDic.items():
        w.writerow([k, v])

or as juanpa.arrivillaga pointed out you can writerows directly on the .items() .

with open('myFile.csv', 'w', encoding='utf-8-sig') as f:
    w.writerow(header)
    w.writerows(myDic.items())

However, storing your information for your csv in a dictionary in this way is very limiting since it can only ever be two columns so ensure that is an acceptable choice before continuing down this path.

Answer 2

You are trying to write the entire dictionary as a row. Instead, write each row separately.

Please see here for more details:

https://docs.python.org/3/library/csv.html#csv.DictWriter

As an example please see the following usage:

import csv

myDic = { "a" : 1, "b" : 2, "c" : 15}
with open('myFile.csv', 'w', newline='') as csvfile:
    fieldnames = ['word', 'count']
    writer = csv.DictWriter(csvfile, fieldnames=fieldnames)

    writer.writeheader()
    for key in myDic:
        writer.writerow({'word': key, 'count': myDic[key]})

Let me know if this helps. I didn't test the code... but I may before you see the answer.

Edit Yeah tested, seems to work fine. Best of luck!

Answer 3

This should work

import csv

myDic = { "a" : 1, "b" : 2, "c" : 15}

header = ["word", "count"]

with open('myFile.csv', 'w', encoding='utf-8-sig') as f:
    writer = csv.writer(f)
    writer.writerow(header) # write the header
    for k,v in myDic.items():
        writer.writerow([k,v])

Answer 4

I am a Pandas person so I will give the way of doing this using Pandas

import pandas as pd
myDic = { "a" : 1, "b" : 2, "c" : 15}
header = ["word", "count"]

df = pd.DataFrame.from_dict(myDic, orient='index').reset_index()
df.columns = header
df.to_csv('word_count.csv', index=False)