import re
l=[["123abc","456"],["lmnop0987"]]
list_1=[]
for i,string in enumerate(l):
if i == 0 :
for j in string:
list_1.append(re.findall(r'[0-9]+', j)[0])
print(list_1)
aW1wb3J0IHJlCgpsPVtbIjEyM2FiYyIsIjQ1NiJdLFsibG1ub3AwOTg3Il1dCmxpc3RfMT1bXQpmb3IgaSxzdHJpbmcgaW4gZW51bWVyYXRlKGwpOgogICAgaWYgaSA9PSAwIDoKICAgICAgICBmb3IgaiBpbiBzdHJpbmc6CiAgICAgICAgICAgIGxpc3RfMS5hcHBlbmQocmUuZmluZGFsbChyJ1swLTldKycsIGopWzBdKQpwcmludChsaXN0XzEp