Python中单行匹配的多行输出

Question

我仍然是 Python 的新手，但我正在尝试编写代码来解析来自 NOAA 的天气并按照我们的无线电广播的顺序显示它。

我已经设法整理了一个使用 python 表达式的当前条件列表，其中 html 文件被分割成行列表，然后以正确的顺序重新输出，但每个都是一个行数据。该代码如下所示：

#other function downloads  
#http://www.arh.noaa.gov/wmofcst_pf.php?wmo=ASAK48PAFC&type=public
#and renames it currents.html
from bs4 import BeautifulSoup as bs
import re
soup = bs(open('currents.html')
weatherRaw = soup.pre.string
towns = ['PAOM', 'PAUN', 'PAGM', 'PASA']
townOut = []
weatherLines = weatherRaw.splitlines()
for i in range(len(towns)):
    p = re.compile(towns[i] + '.*')
    for line in weatherLines:
        matched = p.match(line)
        if matched:
            townOut.append(matched.group())

现在我正在处理预测部分，我遇到了一个问题，因为每个预测都必须跨越多行，并且我已将文件切割成行列表。

所以：我正在寻找的是一个允许我使用类似循环的表达式，这次从找到的行开始追加并在仅包含 && 的行结束。像这样的：

#sample data from http://www.arh.noaa.gov/wmofcst.php?wmo=FPAK52PAFG&type=public
#BeautifulSouped into list fcst (forecast.pre.get_text().splitlines())
zones = ['AKZ214', 'AKZ215', 'AKZ213'] #note the out-of-numerical-order zones
weatherFull = []
for i in range(len(zones)):
    start = re.compile(zones[i] '.*')
    end = re.compile('&&')
    for line in fcst:
        matched = start.match(line)
        if matched:
            weatherFull.append(matched.group())
            #and the other lines of various contents and length
            #until reaching the end match object

我应该如何改进这段代码？我知道这很冗长，但是当我开始的时候，我喜欢能够跟踪我在做什么。提前致谢！

Answer 1

抱歉，如果这不是您所追求的（在这种情况下，很乐意调整）。您使用 BeautifulSoup 真是太棒了，但您实际上可以更进一步。查看 HTML，似乎每个块都以 <a name=zone> 结构开始，并在下一个 <a name=zone> 结束。在这种情况下，您可以执行以下操作来为每个区域拉取相应的 HTML：

from bs4 import BeautifulSoup

# I put the HTML in a file, but this will work with a URL as well
with open('weather.html', 'r') as f:
  fcst = f.read()

# Turn the html into a navigable soup object
soup = BeautifulSoup(fcst)

# Define your zones
zones = ['AKZ214', 'AKZ215', 'AKZ213']

weatherFull = []

# This is a more Pythonic loop structure - instead of looping over
# a range of len(zones), simply iterate over each element itself
for zone in zones:
  # Here we use BS's built-in 'find' function to find the 'a' element
  # with a name = the zone in question (as this is the pattern).
  zone_node = soup.find('a', {'name': zone})

  # This loop will continue to cycle through the elements after the 'a'
  # tag until it hits another 'a' (this is highly structure dependent :) )
  while True:
    weatherFull.append(zone_node)
    # Set the tag node = to the next node
    zone_node = zone_node.nextSibling
    # If the next node's tag name = 'a', break out and go to the next zone
    if getattr(zone_node, 'name', None)  == 'a':
      break

# Process weatherFull however you like
print weatherFull

希望这会有所帮助（或者至少在您想要的范围内！）。