在Python中讀取文件時忽略行

Question

我的程序的第一部分要求我讀取文件但忽略前幾行。 我讀過的文件看起來像：

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

我的問題是，如何讀取文件中的所有行但忽略%%及其上面的每一行？

Answer 1

只需讀取並轉儲線，直到找到所需的線。 文件迭代器執行內部緩沖，因此您可以根據之后要執行的操作進行不同的操作。

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)

也許

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())

Answer 2

with open("in.txt") as f:
    start = False
    for line in f:
        if "%%" in line:
            start = True
        if start: # if True we have found the section we want
            for line in f:
                 print(line)
   More Blah.

Answer 3

你可以使用一個標志：

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

Answer 4

你可以使用iter兩個參數版本：

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,

這將迭代，直到第一個arg（函數）返回的值不等於第二個。