在Python中读取文件时忽略行

程序的第一部分要求我读入文件，但忽略前几行。我在中读取的文件如下所示：

Blah
Blah
Blah
some character(%% for example)
More Blah.

---

我的问题是，我如何读取文件中的所有行，而忽略%%及其上方的每一行？

只需读取并转储行，直到找到所需的行为止。文件迭代器执行内部缓冲，因此您可以根据以后要执行的操作进行不同的操作

with open('somefile') as f:
    # ignore up to the first line with "%%"
    for line in f:
        if "%%" in line:
            break
    # then process the rest
    for line in f:
        do_amazing_stuff(line)

或许

with open('somefile') as f:
    # ignore up to the first line with "%%"
    while True:
        line = f.readline()
        if not line or "%%" in line:
            break
    # then process the rest
    do_amazing_stuff(f.read())

您可以使用标志：

with open('myfile.txt') as fd:
    skip = True
    for line in fd:
        if line.startswith("*"): skip = False
        if not skip:
            # process line

---

您可以使用iter的两个参数版本：

with open('iter.txt') as f:
    for line in iter(f.readline, '%%\n'):
    # for line in iter(lambda: f.readline().startswith('%%'), True):
    # for line in iter(lambda: '%%' in f.readline(), True):
        pass
    for line in f:
        print line,

这将迭代，直到第一个参数（函数）返回的值不等于第二个参数

with open('iter.txt') as f:
    for line in iter(f.readline, '%%\n'):
    # for line in iter(lambda: f.readline().startswith('%%'), True):
    # for line in iter(lambda: '%%' in f.readline(), True):
        pass
    for line in f:
        print line,