with open('document.csv','a') as fd:
    fd.write(myCsvRow)

Opening a file with the 'a' parameter allows you to append to the end of the file instead of simply overwriting the existing content. Try that.

Answer from brettkelly on Stack Overflow
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GeeksforGeeks
geeksforgeeks.org › python › how-to-append-a-new-row-to-an-existing-csv-file
How to append a new row to an existing csv file? - GeeksforGeeks
July 23, 2025 - From the NumPy library, savetxt() ... string data if formatted properly. To append a row, open the file in 'ab' (append binary) mode and write using savetxt() with fmt='%s'....
Discussions

How to append values to specific columns and rows in csv?
This is unclear. You say "How do I append?", then "Here's what I'm trying to do", followed only by a bunch of print statements which have nothing to do with appending to a file. So it's not really clear what your specific objectives are, what you've tried, and what exactly isn't working/how your end result differs from your target result. In short, you haven't provided enough info for anyone to meaningfully help you. You should show us the full code, or if it's punishingly long, at least all the parts that are relevant to your question. "Keeping things short" is not a virtue if it means excluding critical content. More on reddit.com
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August 20, 2021
python - Is there a way to append rows to an existing csv file while retaining the colors of rows? - Stack Overflow
Suppose I have a csv file and I've changed colors of some rows. Now I have a new csv file that I am downloading from the internet. It has some new rows and some old. I want to find the unique data ... More on stackoverflow.com
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python - How to add pandas data to an existing csv file? - Stack Overflow
The answer from @KCzar considers ... when the CSV is already there (so add just the data rows without headers). In any case it uses the "append" mode and a custom separator, along with checks on the number of columns. ... Save this answer. ... Show activity on this post. You can specify a python write mode ... More on stackoverflow.com
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python - Appending data to existing CSV file by columns/rows - Stack Overflow
I am trying to export data into csv. When I export it, it is exported as a singular row and each additional data is appended on the same row. The result is a very long row which is difficult to nav... More on stackoverflow.com
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Reddit
reddit.com › r/learnpython › appending data in csv file
r/learnpython on Reddit: appending data in csv file
September 8, 2021 -

hey, everyone good day! (I'm very new to this coding stuff)

I was writing a simple program and this program needs to append new data from users to the existing csv file so I wrote this function.

def append_list_as_row(file_name, list_of_elem):
    with open(file_name, 'a+', newline='') as write_obj:
        csv_writer = writer(write_obj)
        csv_writer.writerow(list_of_elem)

this just works fine until the last element from the csv file is 0.

let's say we have [Robert][19][male][173] this kind of data in excel. and this works just fine with the function. but when it's like [Robert][19][male][0], the next appended data will not generate a new row and will continue adding data in the current row and replacing 0 to the first data element from the user.

I hope you guys understand my English...welp, anyways I want this function to work seemly whether the last element is 0 or not. I've been searching the internet for quite a long but I was not able to find the answer. is there any kind soul who can help me?

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Quora
quora.com › In-Python-how-do-I-append-a-user-input-to-a-specific-row-within-an-existing-CSV-file
In Python, how do I append a user input to a specific row within an existing CSV file? - Quora
Quora is a place to gain and share knowledge. It's a platform to ask questions and connect with people who contribute unique insights and quality answers.
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Delft Stack
delftstack.com › home › howto › python › python append to csv
How to Append New Row to a CSV File in Python | Delft Stack
February 2, 2024 - In this case, before we append the new row into the old CSV file, we need to assign the row values to a list. ... Next, pass this data from the List as an argument to the CSV writer() object’s writerow() function.
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Finxter
blog.finxter.com › home › learn python blog › how to append a new row to a csv file in python?
How to Append a New Row to a CSV File in Python? - Be on the Right Side of Change
August 18, 2022 - Python Append Row to CSV To append a row (=dictionary) to an existing CSV, open the file object in append mode using open('my_file.csv', 'a', newline=''). Then create a csv.DictWriter() to append a dict row using DictWriter.writerow(my_dict).
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thisPointer
thispointer.com › home › filehandling › python: how to append a new row to an existing csv file?
Python: How to append a new row to an existing csv file? - thisPointer
September 19, 2020 - This function accepts 3 arguments i.e. a csv file name, dictionary of elements and fields names. Then appends the content of dictionary as a new row in the end of csv file. ... Id,Name,Course,City,Session 21,Mark,Python,London,Morning 22,John,Python,Tokyo,Evening 23,Sam,Python,Paris,Morning 32,Shaun,Java,Tokyo,Morning
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Data Science Parichay
datascienceparichay.com › home › blog › pandas – append dataframe to existing csv
Pandas - Append dataframe to existing CSV - Data Science Parichay
March 27, 2021 - In this tutorial, we’ll look at how to append a pandas dataframe to an existing CSV file. To append a dataframe row-wise to an existing CSV file, you can write the dataframe to the CSV file in append mode using the pandas to_csv() function.
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TutorialKart
tutorialkart.com › python › how-to-append-data-to-an-existing-csv-file-using-python
How to Append Data to an Existing CSV File using Python
February 17, 2025 - To append data to an existing CSV file in Python, we use the built-in csv module with the open() function in append mode ('a'). This allows us to add new rows to the file without overwriting the existing content.
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Statology
statology.org › home › pandas: how to append data to existing csv file
Pandas: How to Append Data to Existing CSV File
July 16, 2021 - ‘existing.csv’: The name of the existing CSV file. mode=’a’: Use the ‘append’ mode as opposed to ‘w’ – the default ‘write’ mode.
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Linux Hint
linuxhint.com › append-new-row-csv-python
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YouTube
youtube.com › codemint
python csv append row - YouTube
Instantly Download or Run the code at https://codegive.com in this tutorial, we'll cover how to append rows to an existing csv (comma separated values) file...
Published   March 30, 2024
Views   7
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Reddit
reddit.com › r/learnpython › how to append values to specific columns and rows in csv?
r/learnpython on Reddit: How to append values to specific columns and rows in csv?
August 20, 2021 -

Hello, so I am rather confused with how to take some values that are produced by a python script and then append them to a specific location in a csv file. I initially thought this would be a really simple task with plenty of tutorials online, but most examples I have found seem to overcomplicate things with fancy shortcuts and workarounds, which have just left me confused. Here is what I am trying to do:

I have this .csv file that looks like this containing just this one row intended to be the headers:

Parameter_1   Parameter_2   Parameter_3   Value_1   Value_2

I then have the following python code:

parameters = ['p1_5_p2_4_p3_2', 'p1_3_p2_8_p3_3', 'p1_4_p2_3_p3_6']
Blue = [5, 4, 3]

for parameter in parameters:
    for x in Blue:
        y = x + 1
        z = x + 2
            
        print(parameter)
        print(y)
        print(z)
        print('')     

And then I am returned the following (sorry this goes on for so long!):

p1_5_p2_4_p3_2
6
7

p1_5_p2_4_p3_2
5
6

p1_5_p2_4_p3_2
4
5

p1_3_p2_8_p3_3
6
7

p1_3_p2_8_p3_3
5
6

p1_3_p2_8_p3_3
4
5

p1_4_p2_3_p3_6
6
7

p1_4_p2_3_p3_6
5
6

p1_4_p2_3_p3_6
4
5

where "p" refers to "parameter", and so "p1_5" means "parameter value of 5", etc.

And so I want to append these results to my csv file, so that it looks like this:

Parameter_1   Parameter_2   Parameter_3   Value_1   Value_2
          5             4             2         6         7  
          5             4             2         5         6
          5             4             2         4         5
          3             8             3         6         7
          3             8             3         5         6
          3             8             3         4         5
          4             3             6         6         7
          4             3             6         5         6
          4             3             6         4         5

Is there a simple way to do this in python? I am very confused about how to transpose the results as a row, and then make sure they are sorted under the correct column. I would appreciate any guidance on this! Thank you!

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sqlpey
sqlpey.com › python › top-6-ways-to-append-to-csv
Top 6 Ways to Append a New Row to an Existing CSV File in Python
December 5, 2024 - import csv rows = [['row1_col1', 'row1_col2'], ['row2_col1', 'row2_col2']] with open('existing_file.csv', 'a', newline='') as file: writer = csv.writer(file) writer.writerows(rows) A: The ‘a’ mode opens a file for appending, meaning new data will be added at the end of the file without deleting existing content. In contrast, ‘w’ mode opens a file for writing and will erase any existing content in that file. I welcome any feedback or comments regarding these methods or any additional tips you may have for working with CSV files in Python!
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GitHub
gist.github.com › Nyahua › 7db3056ce2ba6df9ec84dd362eabe686
append new row to old csv file python · GitHub
The key point is using 'a' for appending when you open the file. import csv fields=['first','second','third'] with open(r'name', 'a') as f: writer = csv.writer(f) writer.writerow(fields) You may experience superfluous new lines in Windows.
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GeeksforGeeks
geeksforgeeks.org › python › how-to-append-pandas-dataframe-to-existing-csv-file
How to Append Pandas DataFrame to Existing CSV File? - GeeksforGeeks
July 23, 2025 - To achieve this, we can utilize the to_csv() function in Pandas with the 'a' parameter to write the DataFrame to the CSV file in append mode. ... index: False means do not include an index column when appending the new data.
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Sololearn
sololearn.com › en › Discuss › 2672086 › python-how-can-i-append-data-to-a-csv-file-without-overwriting-other-colums
Python how can I append data to a csv file without over-writing other colums? | Sololearn: Learn to code for FREE!
This is what I mean: open("myfile.csv", "a") The "a" lets you add new rows at the end of the file without overwriting existing rows. Also if the file does net yet exist, then it creates the file for you and lets you write to it. So I had in mind that you wanted to add more rows.