# intialize list to store video captions
transcript_text_list = []

# loop through each row of dataframe
for i in range(len(df)):

    # try to extract captions
    try:
        # get transcript
        transcript = YouTubeTranscriptApi.get_transcript(df['video_id'][i])
        # extract text transcript
        transcript_text = extract_text(transcript)
    # if not captions available set as n/a
    except:
        transcript_text = "n/a"

    # append transcript text to list
    transcript_text_list.append(transcript_text)