Writing Python Lists to Columns in Csv

Writing Python lists to columns in csv

Change them to rows:

rows = zip(list1, list2, list3, list4, list5)

Then just:

import csv

with open(newfilePath, "w") as f:
    writer = csv.writer(f)
    for row in rows:
        writer.writerow(row)

Writing a Python list into a single CSV column

With Python3, open the file in w mode:

with open('returns.csv', 'w') as f:
    writer = csv.writer(f)
    for val in daily_returns:
        writer.writerow([val])

With Python2.6+, open the file in wb mode:

with open('returns.csv', 'wb') as f:
    writer = csv.writer(f)
    for val in daily_returns:
        writer.writerow([val])

How to turn a list into a column in a csv?

To perform this task I would use pandas package as follows:

import pandas as pd
l=["a","b","c","d"]
df=pd.DataFrame(l,index=False,header=False)
df.to_csv("twitter3.csv")

pandas is also great to read csv and even work with Excel files.

Write a list of values as separate columns to a CSV file using Python

You are iterating over the list row and writing each element as a new row in your code when you do writer.writerow([item]).

Instead you want to write the entire row in one line using writer.writerow

import csv

row=['ABC','XYZ','','','ABCD','']  #my list looks like this every time

with open('some.csv', 'w') as writeFile:

    writer = csv.writer(writeFile, delimiter=',', quotechar='"')
    #Write the list in one row
    writer.writerow(row)

The file will look like

ABC,XYZ,,,ABCD,

Write list of lists to CSV file. Putting sub-lists into individual columns

Use following code snippet:

import pandas as pd
cols = ['a', 'b', 'c', 'd']
d = [dict(zip(cols, vals)) for vals in results]
pd.DataFrame(d).to_csv('C:\Users\out.csv')

In case you want to append to existing csv file, change last line to:

pd.DataFrame(d).to_csv('C:\Users\out.csv', mode='a', header=False)

This is how your dataframe looks:

    a   b   c          d
0  11  22  33  [1, 2, 3]
1  44  55  66  [4, 5, 6]

A Way To Store Unknown Amount Of Separate Lists As Columns In A csv File (Python)?

You could try something like:

Step 1: Create file csv file if not already exist
Step 2: Read the csv file to memory
Step 3: Get the user input and append to the data you read from the csv ( can be looped if there are multiple entries to be read)
Step 4: Write back the data (not append but as new file with the same name)

Implementation:

from pathlib import Path
import csv


def read_existing_data(filename):
    csv_file = Path(filename)
    csv_file.touch(exist_ok=True)
    input_data = [row for row in csv.DictReader(open(filename))]
    return input_data


def get_user_input():
    entry_list = list()
    entry = dict()
    true = 'yes'

    while true:
        user_entry = input("Do you want an entry? 'yes' to continue, ('no' to stop): ")
        if user_entry == 'no':
            break
        else:
            entry["full_name"] = input("Enter a full name: ")
            entry["first_time"] = float(input("Enter first time: "))
            entry["second_time"] = float(input("Enter second time: "))
            entry["third_time"] = float(input("Enter third time: "))
        entry_list.append(entry)
    return entry_list


def save_to_file(filename, csv_data):
    columns = csv_data[0].keys()
    try:
        with open(filename, 'w') as csvfile:
            writer = csv.DictWriter(csvfile, fieldnames=columns)
            writer.writeheader()
            for rows in csv_data:
                writer.writerow(rows)
    except IOError:
        print("I/O error")


file_name = "times.csv"
# Read Existing data
data = read_existing_data(file_name)
# Append new data
data.extend(get_user_input())
# Save to file
save_to_file(file_name, data)

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