How to iterate over rows from column1 and modify column2 depending on whether regex is matched in co-CodePudding

I wish to add a column to my document indicating whether or not my regex was matched in another column. Such as to go from:

Column A
word regex word
word word word
word word word
word regex word

Column A	Column B
word regex word	True
word word word	False
word word word	False
word regex word	True

I doubled checked my regex and it works just fine, so the problem does not come from that.

I tried

iterating over the rows and changing them depending on whether the regex is matched

for row in FILE.itertuples():
       if FILE.COLUMNTOSEARCH.contains(REGEX):
            FILE.at[row.Index, "NEWCOLUMN"] = "string1"
       else:
            FILE.at[row.Index, "NEWCOLUMN"] = "string2"

This returns the error: "AttributeError: 'Series' object has no attribute 'contains'"

duplicating the first column and then using replace

FILE.replace(REGEX, regex=True, value="string1", inplace=True)
FILE.replace(REGEX, regex=False, value="string2", inplace=True)

For this, only the "string1" appears, and it doesnt replace the whole row, just where the regex is found although I wish to for "string1" to be the only string in the entry.

I've looked at all the stackoverflow possible documentation without being able to figure anything. I feel like both those solutions are highly inefficient but cannot understand how to write something better. Thanks in advance for any help/solution.

CodePudding user response：

You can use .str.contains:

df["Column B"] = df["Column A"].str.contains(r"\bregex\b")

This outputs:

          Column A  Column B
0  word regex word      True
1  word word word      False
2  word word word      False
3  word regex word      True