Pandas select and write rows that contain certain text

Question

I want to keep only rows in a dataframe that contains specific text in column "col" . In this example either "WORD1" or "WORD2" .

df = df["col"].str.contains("WORD1|WORD2")
df.to_csv("write.csv")

This returns True or False . But how do I make it write entire rows that match these critera, not just present the boolean?

Answer 1

What is returned is a boolean series you use that to filter the df:

df = df[df["col"].str.contains("WORD1|WORD2")]

You can then write this out as normal:

df.to_csv("write.csv")

Example:

In [14]:    
df = pd.DataFrame({'col':['word', 'WORD1', 'WORD2', 'WORD3']})
df

Out[14]:
     col
0   word
1  WORD1
2  WORD2
3  WORD3

In [15]:    
df[df['col'].str.contains('WORD1|WORD2')]

Out[15]:
     col
1  WORD1
2  WORD2