import re
regex = re.compile(r"<iframe[\s]+?src=\"(http[s]*:\/\/)?www\.youtube\.com\/embed\/([a-zA-Z0-9-_]{11})[^\"]*\"[^>]*?><\/iframe>")
test_str = ("<iframe src=\"https://www.youtube.com/embed/lfLRV19y6hg?disablekb=1&rel=0&showinfo=0\" width=\"780\" height=\"439\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"></iframe>\n\n"
"<iframe src=\"https://www.youtube.com/embed/3xzCyOdf4Qc?disablekb=1&rel=0&showinfo=0\" width=\"780\" height=\"439\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"></iframe>\n\n"
"<iframe src=\"https://www.youtube.com/embed/JtpT4LLxFv4?disablekb=1&rel=0&showinfo=0\" width=\"780\" height=\"440\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"></iframe>\n\n"
"<iframe src=\"https://www.youtube.com/embed/R6UAHzmxJ_g?disablekb=1&rel=0&showinfo=0\" width=\"780\" height=\"439\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"></iframe>\n\n"
"<iframe src=\"https://www.youtube.com/embed/DIFGObcX9A4?disablekb=1&rel=0&showinfo=0\" width=\"780\" height=\"439\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"></iframe>\n\n"
"<iframe src=\"https://www.youtube.com/embed/HtDEqzAk_48?disablekb=1&rel=0&showinfo=0\" width=\"780\" height=\"439\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"></iframe>\n\n"
"<iframe src=\"https://www.youtube.com/embed/n5GpN1Xa4q0?disablekb=1&rel=0&showinfo=0\" width=\"780\" height=\"439\" frameborder=\"0\" allowfullscreen=\"allowfullscreen\"></iframe>")
matches = regex.finditer(test_str)
for match_num, match in enumerate(matches, start=1):
print(f"Match {match_num} was found at {match.start()}-{match.end()}: {match.group()}")
for group_num, group in enumerate(match.groups(), start=1):
print(f"Group {group_num} found at {match.start(group_num)}-{match.end(group_num)}: {group}")
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Python, please visit: https://docs.python.org/3/library/re.html