如何更改pandas列中数字的格式？

Question

I have a large DataFrame of numbers but each individual number follows a different format. I want to use a regular expression to replace a large amount of them with a 111-111-1111 format

numbers["numbers"].replace('^(\+\d{1,2}\s)?\(?\d{3}\)?[\s.-]?\d{3}[\s.-]?\d{4}$, "/*/*/*-/*/*/*-/*/*/*/*", regex=True')

it should take a number found by the expression and keep the base number but change its format. 1234567890 should equal 123-456-7890

Answer 1

You may use

df["numbers"] = df["numbers"].str.replace('^(?:\+\d{1,2}\s)?\(?(\d{3})\)?[\s.-]?(\d{3})[\s.-]?(\d{4})$', r'\1-\2-\3')

Details

• ^ - start of string
• (?:\\+\\d{1,2}\\s)? - an optional sequence of
• \\(? - an optional (
• (\\d{3}) - Group 1: three digits
• \\)? - an optional )
• [\\s.-]? - an optional whitespace, . or -
• (\\d{3}) - Group 2: three digits
• [\\s.-]? - an optional whitespace, . or -
• (\\d{4}) - Group 3: four digits
• $ - end of string.

The \\x in the replacement pattern ( r'\\1-\\2-\\3' ) are placeholders for the values captured with corresponding groups.