国产av日韩一区二区三区精品,成人性爱视频在线观看,国产,欧美,日韩,一区,www.成色av久久成人,2222eeee成人天堂

Table of Contents
How do I handle CSV file operations in Python?
Reading a CSV File
Writing a CSV File
Example: Reading and Writing a CSV File
Using Pandas for CSV Handling
Common CSV File Endings
Working with CSV Data
Alternatives to CSV
Home Backend Development Python Tutorial How to Efficiently Read and Write CSV Files in Python?

How to Efficiently Read and Write CSV Files in Python?

Dec 24, 2024 pm 07:00 PM

How to Efficiently Read and Write CSV Files in Python?

How do I handle CSV file operations in Python?

CSV (Comma Separated Values) files are a common method for storing tabular data in a text file. Python has a standard library that supports both reading and writing CSV files.

Reading a CSV File

To read a CSV file into a list of tuples, you can use the csv module as follows:

import csv

with open('myfile.csv', 'r') as f:
    reader = csv.reader(f)
    data = [row for row in reader]

Writing a CSV File

To write a list of tuples to a CSV file, you can use the csv module as follows:

import csv

with open('myfile.csv', 'w') as f:
    writer = csv.writer(f)
    writer.writerows(data)

Example: Reading and Writing a CSV File

Here is an example that shows how to read and write a CSV file:

import csv

# Define the CSV data
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)
]

# Write the data to a CSV file
with open('myfile.csv', 'w') as f:
    writer = csv.writer(f)
    writer.writerows(data)

# Read the data from the CSV file
with open('myfile.csv', 'r') as f:
    reader = csv.reader(f)
    data_read = [row for row in reader]

# Print the data
print(data_read)

Using Pandas for CSV Handling

Pandas is a popular Python library for data analysis that provides a convenient way to handle CSV files. You can use Pandas to read a CSV file into a DataFrame, which you can then manipulate and save as a CSV file.

import pandas as pd

# Read the CSV file into a DataFrame
df = pd.read_csv('myfile.csv', index_col=0)

# Make some changes to the DataFrame
df['Amount'] *= 2

# Write the DataFrame to a new CSV file
df.to_csv('new_myfile.csv')

Common CSV File Endings

The most common file ending for CSV files is .csv. Other less common endings include .txt and .dat.

Working with CSV Data

Once you have read a CSV file into a list of tuples, a list of dicts, or a Pandas DataFrame, you can work with the data using standard Python methods. For example, you can loop over the data, access individual values, or perform calculations on the data.

Alternatives to CSV

In addition to CSV, there are other data formats that you can use in Python. Some common alternatives include:

  • JSON: A popular format for storing data in a human-readable format.
  • YAML: A format that is similar to JSON but is more verbose and human-readable.
  • Pickle: A Python-specific format that can serialize any Python object.
  • MessagePack: A binary format that is more compact than JSON or YAML.

The above is the detailed content of How to Efficiently Read and Write CSV Files in Python?. For more information, please follow other related articles on the PHP Chinese website!

Statement of this Website
The content of this article is voluntarily contributed by netizens, and the copyright belongs to the original author. This site does not assume corresponding legal responsibility. If you find any content suspected of plagiarism or infringement, please contact admin@php.cn

Hot AI Tools

Undress AI Tool

Undress AI Tool

Undress images for free

Undresser.AI Undress

Undresser.AI Undress

AI-powered app for creating realistic nude photos

AI Clothes Remover

AI Clothes Remover

Online AI tool for removing clothes from photos.

ArtGPT

ArtGPT

AI image generator for creative art from text prompts.

Stock Market GPT

Stock Market GPT

AI powered investment research for smarter decisions

Hot Tools

Notepad++7.3.1

Notepad++7.3.1

Easy-to-use and free code editor

SublimeText3 Chinese version

SublimeText3 Chinese version

Chinese version, very easy to use

Zend Studio 13.0.1

Zend Studio 13.0.1

Powerful PHP integrated development environment

Dreamweaver CS6

Dreamweaver CS6

Visual web development tools

SublimeText3 Mac version

SublimeText3 Mac version

God-level code editing software (SublimeText3)

How to automate data entry from Excel to a web form with Python? How to automate data entry from Excel to a web form with Python? Aug 12, 2025 am 02:39 AM

The method of filling Excel data into web forms using Python is: first use pandas to read Excel data, and then use Selenium to control the browser to automatically fill and submit the form; the specific steps include installing pandas, openpyxl and Selenium libraries, downloading the corresponding browser driver, using pandas to read Name, Email, Phone and other fields in the data.xlsx file, launching the browser through Selenium to open the target web page, locate the form elements and fill in the data line by line, using WebDriverWait to process dynamic loading content, add exception processing and delay to ensure stability, and finally submit the form and process all data lines in a loop.

What are class methods in Python What are class methods in Python Aug 21, 2025 am 04:12 AM

ClassmethodsinPythonareboundtotheclassandnottoinstances,allowingthemtobecalledwithoutcreatinganobject.1.Theyaredefinedusingthe@classmethoddecoratorandtakeclsasthefirstparameter,referringtotheclassitself.2.Theycanaccessclassvariablesandarecommonlyused

HDF5 Dataset Name Conflicts and Group Names: Solutions and Best Practices HDF5 Dataset Name Conflicts and Group Names: Solutions and Best Practices Aug 23, 2025 pm 01:15 PM

This article provides detailed solutions and best practices for the problem that dataset names conflict with group names when operating HDF5 files using the h5py library. The article will analyze the causes of conflicts in depth and provide code examples to show how to effectively avoid and resolve such problems to ensure proper reading and writing of HDF5 files. Through this article, readers will be able to better understand the HDF5 file structure and write more robust h5py code.

python asyncio queue example python asyncio queue example Aug 21, 2025 am 02:13 AM

asyncio.Queue is a queue tool for secure communication between asynchronous tasks. 1. The producer adds data through awaitqueue.put(item), and the consumer uses awaitqueue.get() to obtain data; 2. For each item you process, you need to call queue.task_done() to wait for queue.join() to complete all tasks; 3. Use None as the end signal to notify the consumer to stop; 4. When multiple consumers, multiple end signals need to be sent or all tasks have been processed before canceling the task; 5. The queue supports setting maxsize limit capacity, put and get operations automatically suspend and do not block the event loop, and the program finally passes Canc

How to handle large datasets in Python that don't fit into memory? How to handle large datasets in Python that don't fit into memory? Aug 14, 2025 pm 01:00 PM

When processing large data sets that exceed memory in Python, they cannot be loaded into RAM at one time. Instead, strategies such as chunking processing, disk storage or streaming should be adopted; CSV files can be read in chunks through Pandas' chunksize parameters and processed block by block. Dask can be used to realize parallelization and task scheduling similar to Pandas syntax to support large memory data operations. Write generator functions to read text files line by line to reduce memory usage. Use Parquet columnar storage format combined with PyArrow to efficiently read specific columns or row groups. Use NumPy's memmap to memory map large numerical arrays to access data fragments on demand, or store data in lightweight data such as SQLite or DuckDB.

How to use regular expressions with the re module in Python? How to use regular expressions with the re module in Python? Aug 22, 2025 am 07:07 AM

Regular expressions are implemented in Python through the re module for searching, matching and manipulating strings. 1. Use re.search() to find the first match in the entire string, re.match() only matches at the beginning of the string; 2. Use brackets() to capture the matching subgroups, which can be named to improve readability; 3. re.findall() returns all non-overlapping matches, and re.finditer() returns the iterator of the matching object; 4. re.sub() replaces the matching text and supports dynamic function replacement; 5. Common patterns include \d, \w, \s, etc., you can use re.IGNORECASE, re.MULTILINE, re.DOTALL, re

How to pass command-line arguments to a script in Python How to pass command-line arguments to a script in Python Aug 20, 2025 pm 01:50 PM

Usesys.argvforsimpleargumentaccess,whereargumentsaremanuallyhandledandnoautomaticvalidationorhelpisprovided.2.Useargparseforrobustinterfaces,asitsupportsautomatichelp,typechecking,optionalarguments,anddefaultvalues.3.argparseisrecommendedforcomplexsc

How to flatten a nested list or a list of lists in Python How to flatten a nested list or a list of lists in Python Aug 12, 2025 am 09:49 AM

FlatteninganestedlistinPythonconvertsalistwithsublistsintoasingleflatlist,andthebestmethoddependsonthenestingdepthanddatasize.Forone-levelnesting,uselistcomprehensionlike[itemforsublistinnested_listforiteminsublist]oritertools.chain.from_iterable(nes

See all articles