Python：csv.writerow（）逐字符拆分关键字符？

Question

Given:

import csv
def writeToCsv(rows):
    with open('results.csv', 'w') as csvfile:
        fieldnames = ['Name', '#Reviews', 'Address', 'Phone']
        writer = csv.DictWriter(csvfile, fieldnames=fieldnames)

        writer.writeheader()
        for row in rows:
            writer.writerow(row)

When I attempt:

row = {
    'Name': self.validEntries.keys()[0],
    '#Reviews': self.validEntries.values()[0],
    'Address': (nap[0] + ', ' + nap[1]),
    'Phone': nap[2]
}
writeToCsv(row)

I get:

ValueError: dict contains field not in fieldnames: 'P', 'h', 'o', 'n', 'e'

Why is writerow splitting this field (I imagine it will do the same for each field) character by character?

Answer 1

You should pass the dictionary into the writer.writerow , instead of passing each key into the write rows seperately.

Also, if you want to write multiple rows (meaning list of multiple dictionaries) into the csv together, you can use - writer.writerows(rows) passing the list of diciontaries into it.

Example -

import csv
with open('results.csv', 'w') as csvfile:
    fieldnames = ['Name', '#Reviews', 'Address', 'Phone']
    writer = csv.DictWriter(csvfile, fieldnames=fieldnames)
    row = {'Name':'Blah','#Reviews':'Blah','Address':'Blah','Phone':'Blah'}
    writer.writeheader()
    writer.writerow(row)
    rows = [{'Name':'Blah2','#Reviews':'Blah2','Address':'Blah2','Phone':'Blah2'},{'Name':'Blah1','#Reviews':'Blah1','Address':'Blah1','Phone':'Blah1'}]
    writer.writerows(rows)

After this the results.csv looks like -

Name,#Reviews,Address,Phone
Blah,Blah,Blah,Blah
Blah2,Blah2,Blah2,Blah2
Blah1,Blah1,Blah1,Blah1

In your case you need to use writer.writerow(rows) without looping through the rows.

Or you can also send in a list of rows as writeToCsv([row]) , but then still you do not need to iterate over the rows, you should use writer.writerows() to write the rows into the dictionary. (notice the extra s )

Answer 2

I think you have to change the code to:

row = {'Name': self.validEntries.keys()[0], '#Reviews' : self.validEntries.values()[0], 'Address' : (nap[0] + ', ' + nap[1]), 'Phone': nap[2]}
writeToCsv([row])

Your writeToCsv expecting a list not a dict.