How to Read and Write CSV Files in Python?

How to Read and Write CSV Files

Reading CSV Files

To read data from a CSV file, use the Python CSV library. Here's an example:

import csv

# Open the CSV file for reading
with open("test.csv", "rt") as f:
    # Create a CSV reader object
    reader = csv.reader(f, delimiter=",", quotechar='"')

    # Iterate over the rows in the CSV file
    for row in reader:
        print(row)

Writing CSV Files

To write data to a CSV file, also use the Python CSV library:

import csv

# Create a list of data to write to the CSV file
data = [
    (1, "A towel", 1.0),
    (42, " it says, ", 2.0),
    (1337, "is about the most ", -1),
    (0, "massively useful thing ", 123),
    (-2, "an interstellar hitchhiker can have.", 3),
]

# Open the CSV file for writing
with open("test.csv", "wt") as f:
    # Create a CSV writer object
    writer = csv.writer(f, delimiter=",", quotechar='"')

    # Write the data to the CSV file
    writer.writerows(data)

Considerations

When working with CSV files:

• Python reads CSV files only as strings. Convert to the desired column types manually.
• Use pandas for advanced data manipulation and visualization.
• Consider alternative data formats like JSON, YAML, or pickle.

Created CSV File

The following is the output of the example code:

1,"A towel,",1.0
42," it says, ",2.0
1337,is about the most ,-1
0,massively useful thing ,123
-2,an interstellar hitchhiker can have.,3

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