python - Python 3，增量迭代器

Question

我正在逐行处理文件。检查每一行是否包含给定的文本。然后，下一行需要分配给变量

i_line = iter(file)
for i_line in file:
    if text in i_line:
         #Go to the next line
         line = next(i_line, None) #A problem
         break

如何增加迭代器 i_line 以指向文件的下一行？两种结构都不适合我

next(i_line, None)
i_line.next()

Answer 1

做吧next(f)。

就像是

>>> with open('testFile.txt', 'r') as f:
        for line in f:
            if 'cat' in line:
                final_string = next(f)

因此，对于输入文本文件

My Name is ABC.
I am a male.
My pet is a cat.
It's name is Ronald.
I hate rats.

上面的代码给出

>>> final_string
"It's name is Ronald.\n"

Answer 2

这是一种使用next().

with open(filename) as file:
    line = next(file, None)
    while line:
        print(line.strip())
        line=next(file, None)

使用for line in file迭代器并next每隔一行打印一次：

with open(filename) as file:
    for line in file:
        print(line.strip())
        line = next(file,None)

Answer 3

使用line = file.next()而不是line = next(i_line, None).