How to fetch values in quotes using python

I have an XML file and I parsed in the d开发者_运维问答ata of the xml file to get a list as below:

humidity data="Humidity: 73%" icon data="/ig/images/weather/cloudy.gif" wind_condition data="Wind: N at 5 mph"

I want to write a python code where I can capture only the values in quotes and put it in a list.

The following code shows how to parse XML using a proper XML parser. The xml stream is reconstructed from the partial information that you have supplied.

xml_strg = """<?xml version="1.0"?>
<xml_api_reply version="1">
    <weather module_id="0" tab_id="0" mobile_row="0" mobile_zipped="1" row="0" section="0" >
        <forecast_information>
            <city data="Baton Rouge, LA"/>
            <postal_code data="baton rouge,la"/>
            <latitude_e6 data=""/>
            <longitude_e6 data=""/>
            <forecast_date data="2011-02-22"/>
            <current_date_time data="2011-02-22 20:06:59 +0000"/>
            <unit_system data="US"/>
        </forecast_information>
        <current_conditions>
            <condition data="Cloudy"/>
            <temp_f data="72"/>
            <temp_c data="22"/>
            <humidity data="Humidity: 73%"/>
            <icon data="/ig/images/weather/cloudy.gif"/>
            <wind_condition data="Wind: N at 5 mph"/>
        </current_conditions>
    </weather>
</xml_api_reply>
"""        

import xml.etree.cElementTree as et

root =  et.fromstring(xml_strg)
result = []
for elem in root.find('./weather/current_conditions'):
    if elem.tag in ('humidity', 'icon', 'wind_condition'):
        result.append(elem.get('data'))
print result

Output:

['Humidity: 73%', '/ig/images/weather/cloudy.gif', 'Wind: N at 5 mph']

What you show above isn't really a list, so we need to know how your data object really looks. For instance, if you have your example in a single string, like:

'humidity data="Humidity: 73%" icon data="/ig/images/weather/cloudy.gif" wind_condition data="Wind: N at 5 mph"'

You can parse this string to get all quoted parts in a list as follows:

import re
re.findall('\"(.+?)\"', in_string)

This uses non-greedy matching to find all substrings that match a beginning and end quote, the text in between is fetched using the parenthesis. See the full details of regular expressions here: docs.python.org

The following will extract all condition blocks from your response, returning them in a list of dicts. From there you can get whatever you need.

#!/usr/bin/env python

from xml.etree.ElementTree import XML
import sys
data = """<?xml version="1.0"?>
<xml_api_reply version="1">
<weather module_id="0" tab_id="0" mobile_row="0" mobile_zipped="1" row="0" section="0">
    <forecast_information>
        <city data="Baton Rouge, LA"/>
        <postal_code data="baton rouge,la"/>
        <latitude_e6 data=""/>
        <longitude_e6 data=""/>
        <forecast_date data="2011-02-22"/>
        <current_date_time data="2011-02-22 20:06:59 +0000"/>
        <unit_system data="US"/>
    </forecast_information>
    <current_conditions>
        <condition data="Cloudy"/>
        <temp_f data="72"/>
        <temp_c data="22"/>
        <humidity data="Humidity: 73%"/>
        <icon data="/ig/images/weather/cloudy.gif"/>
    </current_conditions>
</weather>
</xml_api_reply>
"""

tree = XML(data)
conditions = tree.findall("weather/current_conditions")
results = []
for c in conditions:
    curr_results = {}
    for child in c.getchildren():
        curr_results[child.tag] = child.get('data')
    results.append(curr_results)

print results

With this text (note that I added <icon data="([^"]*)"/><wind_condition data="([^"]*)"/> at the end because this part isn't in your example) in a file called 'joeljames.txt' :

<?xml version="1.0"?><xml_api_reply version="1"><weather module_id="0" tab_id="0" mobile_row="0" mobile_zipped="1" row="0" section="0" ><forecast_information><city data="Baton Rouge, LA"/><postal_code data="baton rouge,la"/><latitude_e6 data=""/><longitude_e6 data=""/><forecast_date data="2011-02-22"/><current_date_time data="2011-02-22 20:06:59 +0000"/><unit_system data="US"/></forecast_information><current_conditions><condition data="Cloudy"/><temp_f data="72"/><temp_c data="22"/><humidity data="Humidity: 73%"/><icon data="/ig/images/weather/cloudy.gif"/><wind_condition data="Wind: N at 5 mph"/>

the following short code

import re

with open('joeljames.txt','rb') as f:
    RE = ('humidity data="([^"]*)"/>'
          '<icon data="([^"]*)"/>'
          '<wind_condition data="([^"]*)"/>')
    print re.search(RE,f.read()).groups()

or even

import re
print re.search(('humidity data="([^"]*)"/>'
                 '<icon data="([^"]*)"/>'
                 '<wind_condition data="([^"]*)"/>'),
                open('joeljames.txt','rb').read()).groups()

have result:

('Humidity: 73%', '/ig/images/weather/cloudy.gif', 'Wind: N at 5 mph')

Nothing more.

I know than the priests of XML parsers will say that yoooou MUST use an XML parser because there are some that are very efficient and a coder must be lazy and etc... They are right in case what must be obtained requires complex algorithm.

But in case of a simple aim as here, I think justified not to resort to an XML parser, moreover if one doesn't know to use one. Do you ?

For my solution, well, you must know regexes, yes... It is necessary to have a minimum of tool when one wants to do something. You must indeed know a language too.....

You can use the parser solution, no problem. But now you know that it's possible with regexes too and you can choose.

EDIT:

To answer to critics that the order of elements may not be always the same:

import re
print dict(re.findall('(humidity data|icon data|wind_condition data)'
                      '="([^"]*)"/>',open('joeljames.txt','rb').read()))

prints

{'humidity data': 'Humidity: 73%', 'icon data': '/ig/images/weather/cloudy.gif', 'wind_condition data': 'Wind: N at 5 mph'}

Here's code that will extract all elements with a data element and convert them into a dictionary:

>>> from lxml import etree
>>> filePath = 'c:/test.xml'
>>> root = etree.parse(filePath)
>>> keypairs = dict((r.tag, r.get('data')) for r in root.xpath('//*[@data]'))

>>> print keypairs
{'city': 'Baton Rouge, LA', 'forecast_date': '2011-02-22', 'latitude_e6': '', 'l
ongitude_e6': '', 'temp_c': '22', 'humidity': 'Humidity: 73%', 'postal_code': 'b
aton rouge,la', 'unit_system': 'US', 'temp_f': '72', 'current_date_time': '2011-
02-22 20:06:59 +0000', 'condition': 'Cloudy', 'icon': '/ig/images/weather/cloudy
.gif'}

>>> print keypairs['humidity']
Humidity: 73%