使用python将带逗号的文本写入CSV文件中的单元格

Question

I want to write text with comma into a cell in CSV file.

Input

'1,2,3,Hello'

Output in CSV should be

'1,2,3','Hello'

Answer 1

Use the proper CSV writers :

>>> import csv
>>> spamWriter = csv.writer(open('eggs.csv', 'wb'))
>>> spamWriter.writerow(['Spam', 'Lovely, Spam'])

Outputs:

Spam,"Lovely, Spam"

Answer 2

This is not Python specific, but is to do with the CSV "standard" .

If you want to write a control character as part of your value, you'll need to escape the value by surrounding it in double-quotes:

f.write('1,2,3,45,"The Next comma I want to write and not separate to another cell, so this sentence will be whole",6,7,8')

Edit: Although in practice, it will be a better idea to use the CSV writer interfaces as suggested by others. It's never a good idea to embroil yourself in the implementation details when there's a ready-rolled library that abstracts this away for you.

Answer 3

Each line of the file is a data record. Each record consists of one or more fields, separated by commas.

The basic idea of separating fields with a comma is clear, but that idea gets complicated when the field data may also contain commas or even embedded line-breaks.

CSV implementations may not handle such field data, or they may use quotation marks to surround the field. -- From https://en.wikipedia.org/wiki/Comma-separated_values

So you can use quotation marks to surround the each field text.

Suppose the input is ['1,2,3', 'Hello'] , the output to CSV should be "1,2,3", "Hello" , you can use codes below to achieve this.

>>> ",".join('"{0}"'.format(s) for s in ['1,2,3', 'Hello'])
'"1,2,3","Hello"'

But you will encounter problems when there are some special symbols such as " , \n and etc in text.

The python csv library has handled all the edge cases for you.

Write to file

Can use @Dominic Rodger answer.

>>> import csv
>>> spamWriter = csv.writer(open('eggs.csv', 'wb'))
>>> spamWriter.writerow(['Spam', 'Lovely, Spam'])

Write to string

From https://stackoverflow.com/a/9157370/5238892 .

In Python 3:

>>> import io
>>> import csv
>>> output = io.StringIO()
>>> csvdata = [1,2,'a','He said "what do you mean?"',"Whoa!\nNewlines!"]
>>> writer = csv.writer(output, quoting=csv.QUOTE_NONNUMERIC)
>>> writer.writerow(csvdata)
59
>>> output.getvalue()
'1,2,"a","He said ""what do you mean?""","Whoa!\nNewlines!"\r\n'

Some details need to be changed a bit for Python 2:

>>> output = io.BytesIO()
>>> writer = csv.writer(output)
>>> writer.writerow(csvdata)
57L
>>> output.getvalue()
'1,2,a,"He said ""what do you mean?""","Whoa!\nNewlines!"\r\n'