Pandas Find – pd.Series.str.find()

If you’re looking for information on how to find data or cell within a Pandas DataFrame or Series, check out a future post – Locating Data Within A DataFrame. This post will be around finding substrings within a series of strings.

Often times you may want to know where a substring exists in a bigger string. You could be trying to extract an address, remove a piece of text, or simply wanting to find the first instance of a substring.

Pandas.Series.Str.Find() helps you locate substrings within larger strings. This has the identical functionality as =find() in Excel or Google Sheets.

Example: “day” is a substring within “Monday.” However, “day” is not a substring of “November,” since “day” does not appear in “November”

Pseudo code: “Monday”.find(“day”) returns 4. “day” starts at the 4th character in “Monday”

But first, what is a string and substring?

• String = Data type within python that represents text
• Substring = A piece of text within a larger piece of text

To find where a substring exists (if it does at all) within a larger series of strings you need to call pd.Series.str.find()

Pandas Find

Pandas find returns an integer of the location (number of characters from the left) of a substring. It will return -1 if it does not exist

Find has two important arguments that go along with the function. Start & End

• Start (default = 0): Where you want .find() to start looking for your substring. By default you’ll start at the beginning of the string (location 0).
• End: Where you want .find() to finish looking for your substring.

Note: You would only use start & end if you didn’t want to search the entire string.

Link to code

Official Documentation