使用正则表达式在 pandas dataframe 中的单词列表之前提取数字

Question

I want to extract only the numbers before a list of specific words. Then put the extracted numbers in a new column.

The list of words is: l = ["car", "truck", "van"] . I only put singular form here, but it should also apply to plural.

df = pd.DataFrame(columns=["description"], data=[["have 3 cars"], ["a 1-car situation"], ["may be 2 trucks"]])

We can call the new column for extracted number df["extracted_num"]

Thank you!

Answer 1

You can use Series.str.extract

l = ["car", "truck", "van"]

pat = f"(\d+)[\s-](?:{'|'.join(l)})"
df['extracted_num'] = df['description'].str.extract(pat)

Output:

>>> print(pat)
(\d+)[\s-](?:car|truck|van)

>>> df

         description extracted_num
0        have 3 cars             3
1  a 1-car situation             1
2    may be 2 trucks             2

Explanation:

• (\d+) - Matches one or more digits and captures the group;
• [\s-] - Matches a single space or hyphen;
• (?:{'|'.join(l)})" - Matches any word from the list l without capturing it.