Question

我有一个小脚本，它从.html文件中提取一些文本。

f = open(local_file,"r")
for line in f:
    searchphrase = '<span class="position'
    if searchphrase in line:
        print("found it\n")

这对我来说很好（稍后会导入错误处理），我的问题是我要提取的文本在搜索短语之后跟随2行。如何在.html文件中向下移动2行？

Answer 1

您可以通过两次调用next()将f（这是一个可迭代的）推进两行：

with open(local_file,"r") as f
    for line in f:
        searchphrase = '<span class="position'
        if searchphrase in line:
            print("found it\n")
            next(f) # skip 1 line
            return next(f)  # and return the line after that.

但是，如果您尝试解析HTML，请考虑使用HTML解析器而不是。例如，使用BeautifulSoup。

Answer 2

这对我很有用：

f = open(local_file,"r")
found = -1
for line in f:
    if found == 2:
        print("Line: "+line);
        break
    elif found > 0:
        found += 1
    else:
        searchphrase = '<span class="position'
        if searchphrase in line:
            print("found it")
            found = 1

输入文件是：

bla
<span class="position">Hello</span>
blub
that's it
whatever

程序的输出：

found it
Line: that's it

您可以将break重置为-1，而不是调用found来搜索模式的更多出现...

Python 3.x：转到下一行

2 个答案: