リンクを新しいタブで開く
  1. 123

    Counting the number of lines in a file is a common task in Python. Below are multiple efficient methods to achieve this:

    1. Using sum() with a Generator

    This is the most memory-efficient method, especially for large files.

    with open("file.txt", "r") as file:
    line_count = sum(1 for _ in file)
    print(f"Total number of lines: {line_count}")
    コピーしました。

    • Explanation: The generator iterates over each line, adding 1 for every line encountered.

    2. Using readlines()

    This method reads all lines into memory, suitable for small files.

    with open("file.txt", "r") as file:
    lines = file.readlines()
    print(f"Total number of lines: {len(lines)}")
    コピーしました。

    • Explanation: readlines() loads all lines into a list, and len() calculates the total count.

    3. Using enumerate()

    Efficiently counts lines while iterating through the file.

    with open("file.txt", "r") as file:
    for count, _ in enumerate(file, 1):
    pass
    print(f"Total number of lines: {count}")
    コピーしました。

    • Explanation: enumerate() assigns an index to each line, starting from 1.

    4. Using a While Loop

    Manually reads each line and increments a counter.

    How to get the number of lines in a file in Python?

    The below example code demonstrates how to use the for loop to get the number of lines in a file in Python. total_lines = sum(1 for line in myfile) print(total_lines) The mmap.mmap(fileno, length) method maps length number of bytes from the file specified by the fileno and returns a mmap object.

    delftstack.com
    Stack Overflow
    https://stackoverflow.com/questions/19001402
    how to count the total number of lines in a text file using python
  1. GeeksForGeeks
    https://www.geeksforgeeks.org › python › count-number...この結果を翻訳する

    Count number of lines in a text file in Python

    2025年12月19日 · Given a text file, the task is to count the number of lines it contains. This is a common requirement in many applications such as processing logs, analyzing datasets, or validating user input.

    geeksforgeeks.org の検索結果のみを表示
  2. Stack Overflow
    https://stackoverflow.com › questionsこの結果を翻訳する

    how to count the total number of lines in a text file using python

    2013年9月25日 · For example if my text file is: blue green yellow black Here there are four lines and now I want to get the result as four. How can I do that?

  3. PYnative
    https://pynative.com › python-count-number-of-lines-in-fileこの結果を翻訳する

    Python Count Number of Lines in a File [5 Ways] – PYnative

    2021年7月2日 · The readlines() method reads all lines from a file and stores it in a list. Next, use the len() function to find the length of the list which is nothing but total lines present in a file.

  5. Tutorial Kart
    https://www.tutorialkart.com › python › how-to-count...この結果を翻訳する

    How to Count the Number of Lines in a File in Python

    To count the number of lines in a file in Python, we can use different methods such as reading the file line by line, using the readlines() method, or iterating over the file object.

  6. TecAdmin
    https://tecadmin.net › count-number-of-lines-in-file-pythonこの結果を翻訳する

    Python Program to Get Line Count of a File – TecAdmin

    2025年4月26日 · In this article, we will discuss how to create a Python program that can count the number of lines in a file. Before we start, ensure that you have Python installed on your computer.

  7. Delft Stack
    https://www.delftstack.com › howto › python › python-get...この結果を翻訳する

    How to Get Number of Lines in a File in Python - Delft Stack

    2024年2月2日 · A simple way to get the number of lines in a file is by iterating through each line of the file object returned by the open() function. The open(file, mode) function takes file as input and …

  8. 他の人も質問しています
    フィードバック
  9. PythonForBeginners.com
    https://www.pythonforbeginners.com › basics › number...この結果を翻訳する

    Number of Lines in a File in Python - PythonForBeginners.com

    2022年2月18日 · Sometimes, we may need to count the number of lines in a file to perform any operation on it. In this article, we will see how we can count the number of lines in a file in python.

  10. GeeksForGeeks
    https://www.geeksforgeeks.org › python › how-to-count...この結果を翻訳する

    How to count the number of lines in a CSV file in Python?

    2025年7月23日 · Counting the number of lines in a CSV file in Python means determining how many rows the file contains, including or excluding the header depending on your needs.

  11. Educative
    https://www.educative.io › answers › how-to-count-the...この結果を翻訳する

    How to count the number of lines, words, and characters in Python

    In this Answer, we'll learn to count the number of lines, words, and characters present in a file. The basic idea is to traverse each line in a file and count the number of words and characters.

  12. vultr.com
    https://docs.vultr.com › ... › get-line-count-of-a-fileこの結果を翻訳する

    Python Program to Get Line Count of a File | Vultr Docs

    In this article, you will learn how to use Python effectively to count the lines in a file. You'll explore different methods including reading the entire file, iterating through each line, and using libraries that …

コンテンツは AI を使用して生成されました。詳細情報