在 Python 中遍历从文件读取的行时如何跳到下一个元素？

Question

我正在尝试编写一个代码来查找文件中的特定文本并获取后面的行。

f = open('programa.txt','r') 
for line in f:
    if (line == "[Height of the board]\n"):
      ## skip to next line and saves its content

    print(line)

Answer 1

设置一个标志，以便您知道抓取下一行。

f = open('programa.txt','r') 
grab_next = False
for line in f:
    if grab_next:
        print(line)
    grab_next = line == "[Height of the board]\n"

Answer 2

文件objects是Python中的迭代器；虽然 for 循环隐式使用迭代器协议，但您可以在需要向前跳过时自己手动调用它：

with open('programa.txt') as f:
    for line in f:
        if line == "[Height of the board]\n":
            # skip to next line and saves its content
            line = next(f)
        print(line)

您的示例代码在哪里存储下一行不清楚，所以我将其存储回 line，使原始行 header 消失。如果目标是仅打印该行并打断，您可以使用：

with open('programa.txt') as f:
    for line in f:
        if line == "[Height of the board]\n":
            # skip to next line and saves its content
            importantline = next(f)
            print(importantline)
            break

Answer 3

当您回顾而不是试图展望未来时，这样的问题几乎总是更简单。毕竟，找出最后一个线是微不足道的；你只需将它存储在一个变量中！在这种情况下，如果 previous 行是 header:

，则您想保存 current 行

f = open('programa.txt', 'r')
last = ""
for line in f:
    if last == "[Height of the board]\n":
        height = int(line.strip())    # for example
        break                         # exit the loop once found (optional)
    last = line

在 Python 中遍历从文件读取的行时如何跳到下一个元素？

How to skip to the next element when iterating over lines read from a file, in Python?

python

iteration