使用 Python 正则表达式提取数据
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Extracting Data with Python Regular Expressions
提问by greyfox
I am having some trouble wrapping my head around Python regular expressions to come up with a regular expression to extract specific values.
我在围绕 Python 正则表达式想出一个正则表达式来提取特定值时遇到了一些麻烦。
The page I am trying to parse has a number of productIds which appear in the following format
我试图解析的页面有许多 productIds，它们以下列格式出现
\"productId\":\"111111\"
I need to extract all the values, 111111in this case.
111111在这种情况下，我需要提取所有值。
采纳答案by perreal
t = "\"productId\":\"111111\""
m = re.match("\W*productId[^:]*:\D*(\d+)", t)
if m:
print m.group(1)
meaning match non-word characters (\W*), then productIdfollowed by non-column characters ([^:]*) and a :. Then match non-digits (\D*) and match and capture following digits ((\d+)).
意思是匹配非单词字符 ( \W*)，然后productId是非列字符 ( [^:]*) 和 a :。然后匹配非数字 ( \D*) 并匹配并捕获以下数字 ( (\d+))。
Output
输出
111111
回答by frickskit
Try this,
尝试这个，
:\"(\d*)\"
Give more examples of your data if this doesn't do what you want.
如果这不能满足您的要求，请提供更多数据示例。
回答by Fredrik Pihl
something like this:
像这样：
In [13]: s=r'\"productId\":\"111111\"'
In [14]: print s
\"productId\":\"111111\"
In [15]: import re
In [16]: re.findall(r'\d+', s)
Out[16]: ['111111']
回答by Tobia
The backslashes here might add to the confusion, because they are used as an escape character both by (non-raw) Python strings and by the regexp syntax.
这里的反斜杠可能会增加混乱，因为它们被（非原始）Python 字符串和正则表达式语法用作转义字符。
This extracts the product ids from the format you posted:
这将从您发布的格式中提取产品 ID：
re_prodId = re.compile(r'\"productId\":\"([^"]+)\"')
The raw string r'...'does away with one level of backslash escaping; the use of a single quote as the string delimiter does away with the need to escape double quotes; and finally the backslashe are doubled (only once) because of their special meaning in the regexp language.
原始字符串r'...'取消了一级反斜杠转义；使用单引号作为字符串分隔符不需要转义双引号；最后，反斜杠加倍（仅一次），因为它们在正则表达式语言中的特殊含义。
You can use the regexp object's findall()method to find all matches in some text:
您可以使用 regexp 对象的findall()方法来查找某些文本中的所有匹配项：
re_prodId.findall(text_to_search)
This will return a list of all product ids.
这将返回所有产品 ID 的列表。
