如何找到字符串中的货币值？ [英] How does one find the currency value in a string?

问题描述

我正在写一个小工具，用于从字符串（通常是一条推文）中提取一堆值。

I'm writing a small tool to extract a bunch of values from a string (usually a tweet).

字符串可以由单词和数字以及以货币符号（£，$，€等）为前缀的金额和一些井号（#foo #bar）。我在appEngine上运行，并使用tweepy引入了推文。

The string could consist of words and numbers along with an amount prefixed by a currency symbol (£,$,€ etc.) and a number of hashtags (#foo #bar). I'm running on appEngine and using tweepy to bring in the tweets.

我现在要查找值的当前代码如下：

The current code I have to find the values is below:

tagex = re.compile(r'#.*')
curex = re.compile(ur'[£].*')
for x in api.user_timeline(since_id = t.lastimport):
          tags = re.findall(tagex, x.text)
          amount = re.findall(curex, x.text)[0]
          logging.info("Text: " + x.text)
          logging.info("Tags: " + str(tags))
          logging.info("Amount: " + amount)

其中x.text例如 Taxi London£6.50 #projectfoo #clientmeeting

where x.text is for example "Taxi London £6.50 #projectfoo #clientmeeting"

tagex发现主题标签很好，但我无法使curx提取当前获得的金额：
金额：£6.50 #projectfoo #clientmeeting。

The tagex finds the hashtags fine, but I can't get curex to extract the amount currently I get: Amount: £6.50 #projectfoo #clientmeeting.

我还需要分离货币符号，以便将其作为浮动金额，但这以后应该很简单。

I also need to separate off the currency symbol so as to get the amount as a float, but that should be pretty simple later.

推荐答案

>>> re.search(ur'([£$€])(\d+(?:\.\d{2})?)', s).groups()
(u'\xa3', u'6.50')

• [ £$€] 匹配一个货币符号


• \d +（?: \.\d {2}）匹配一个或多个数字，后跟一个可选的小数点，然后是恰好两个数字


• （）分别捕获符号和金额


• [£$€] matches one currency symbol
• \d+(?:\.\d{2}) matches one or more digits followed by an optional decimal point followed by exactly two digits
• The ()'s capture the symbol and amount separately

正则表达式的问题是。* 会匹配所有内容并且是贪婪的，因此在正则表达式的末尾它会匹配随后的所有内容。

The problem with your regex is that .* matches anything and is greedy, so at the end of a regex it matches everything that follows.

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