Pandas dataframe：使用条件和切片字符串创建新列

Question

I have this piece of code that creates a new dataframe column, using first a conditional, and then slicing some string, with a fixed slicing index (0, 5):

df.loc[df['operation'] == 'dividend', ['order_adj']] = df['comment'].str.slice(0, 5)

But, instead of having a fixed slicing index, I need to use str.find() at the final of this code, to have a dynamic slice index on df['comment'] , based on its characters.

As I'm creating a new column by broadcasting, I couldn't find the correct sintaxe to use str.find('some_string') inside str.slice() . Thanks.

Answer 1

Option using split :

df['comment'].str.split("some_string").str[0]

Or option using regex (move the capture group to be where you want regarding inclusive/exclusive):

pandas.Series.str.extract("(.*?)some_string")
pandas.Series.str.extract("(.*?some_string)")