Writing data from a python list to csv row-wise

Writing data from a python list to csv row-wise

You can write data from a Python list to a CSV file row-wise using the csv module in Python. Here's an example of how to do it:

import csv # Sample data as a list of lists (each sublist represents a row) data = [ ['Name', 'Age', 'City'], ['John', 30, 'New York'], ['Alice', 25, 'Los Angeles'], ['Bob', 35, 'Chicago'] ] # Define the CSV file name csv_file = 'output.csv' # Write the data to the CSV file row-wise with open(csv_file, 'w', newline='') as file: writer = csv.writer(file) # Loop through the data and write each row for row in data: writer.writerow(row) print(f'Data has been written to {csv_file}')

In this example:

  1. We import the csv module.

  2. We define the data as a list of lists (data), where each sublist represents a row of data, and the first sublist contains the column headers.

  3. We specify the name of the CSV file to write to (csv_file).

  4. We open the CSV file for writing using the open function with the mode 'w'. The newline='' argument is used to ensure that newline characters are handled correctly across different platforms.

  5. We create a csv.writer object (writer) to write data to the CSV file.

  6. We use a for loop to iterate through each row in the data list and write it to the CSV file using writer.writerow(row).

  7. Finally, we print a message confirming that the data has been written to the CSV file.

After running this code, you will have a CSV file named 'output.csv' containing the data from the Python list, with each sublist in the list representing a row in the CSV file.

Examples

  1. Writing a Simple List to CSV Row-wise

    • This query focuses on writing a simple list of values to a CSV file, with each element representing a row.
    import csv data = ['Apple', 'Banana', 'Cherry', 'Date', 'Elderberry'] with open('output.csv', 'w', newline='', encoding='utf-8') as csvfile: writer = csv.writer(csvfile) for item in data: writer.writerow([item]) # Write each element as a separate row

  2. Writing a List of Lists to CSV Row-wise

    • This query discusses writing a list of lists to a CSV file, with each inner list representing a row.
    import csv data = [ ['Name', 'Age', 'City'], ['Alice', 30, 'New York'], ['Bob', 25, 'Los Angeles'] ] with open('output.csv', 'w', newline='', encoding='utf-8') as csvfile: writer = csv.writer(csvfile) for row in data: writer.writerow(row) # Write each list as a row

  3. Appending Data from a List to an Existing CSV Row-wise

    • This query explores appending additional data from a list to an existing CSV file, row-wise.
    import csv new_data = ['Fig', 'Grape', 'Honeydew'] with open('output.csv', 'a', newline='', encoding='utf-8') as csvfile: writer = csv.writer(csvfile) for item in new_data: writer.writerow([item]) # Append each item as a new row

  4. Writing a List of Dictionaries to CSV Row-wise

    • This query demonstrates writing a list of dictionaries to a CSV file, with each dictionary representing a row.
    import csv data = [ {'Name': 'John', 'Age': 35, 'City': 'Boston'}, {'Name': 'Doe', 'Age': 28, 'City': 'Chicago'} ] with open('output.csv', 'w', newline='', encoding='utf-8') as csvfile: fieldnames = data[0].keys() # Get the keys for the headers writer = csv.DictWriter(csvfile, fieldnames=fieldnames) writer.writeheader() # Write the header for record in data: writer.writerow(record) # Write each dictionary as a row

  5. Writing a Nested List to CSV Row-wise

    • This query discusses handling nested lists and writing them to CSV row-wise.
    import csv data = [ ['Group1', ['John', 'Jane', 'Jim']], ['Group2', ['Alice', 'Bob', 'Charlie']] ] with open('output.csv', 'w', newline='', encoding='utf-8') as csvfile: writer = csv.writer(csvfile) for group in data: group_name, members = group for member in members: writer.writerow([group_name, member]) # Write group name and each member as a row

  6. Writing a Transposed List to CSV Row-wise

    • This query explores transposing a list before writing to CSV row-wise.
    import csv data = [ ['Name', 'Alice', 'Bob', 'Charlie'], ['Age', 30, 25, 35], ['City', 'New York', 'Los Angeles', 'Chicago'] ] transposed = list(zip(*data)) # Transpose the list with open('output.csv', 'w', newline='', encoding='utf-8') as csvfile: writer = csv.writer(csvfile) for row in transposed: writer.writerow(row) # Write the transposed rows to CSV

  7. Writing Data with Custom Delimiter to CSV Row-wise

    • This query describes writing a list to CSV row-wise with a custom delimiter, like a semicolon.
    import csv data = ['Apple', 'Banana', 'Cherry', 'Date', 'Elderberry'] with open('output_semicolon.csv', 'w', newline='', encoding='utf-8') as csvfile: writer = csv.writer(csvfile, delimiter=';') # Custom delimiter for item in data: writer.writerow([item]) # Write each item as a separate row

  8. Writing a Mixed Data List to CSV Row-wise

    • This query addresses writing a list with mixed data types to CSV row-wise.
    import csv data = ['Alice', 30, True, 3.14] with open('output.csv', 'w', newline='', encoding='utf-8') as csvfile: writer = csv.writer(csvfile) for item in data: writer.writerow([item]) # Write mixed data types to CSV row-wise

  9. Writing Large Lists to CSV Row-wise with Memory Optimization

    • This query focuses on handling large lists when writing to CSV row-wise with memory optimization.
    import csv # Simulate a large list with a generator to reduce memory usage data = (f"Item {i}" for i in range(10000)) # Generator to create a large list with open('large_output.csv', 'w', newline='', encoding='utf-8') as csvfile: writer = csv.writer(csvfile) for item in data: writer.writerow([item]) # Write large list to CSV row-wise

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