lst = [['abc', 'def',1,11],['cde', 'fef',2,22],['efg', 'pqr',3,33]]
result = []
for l in lst:
res = []
for i, s in enumerate(l):
if isinstance(s, str):
if len(res) > 0 and isinstance(res[i-1], str):
res[i-1] += f" {s}"
else:
res.append(s)
else:
res.append(s)
result.append(res)
print(result)
bHN0ID0gW1snYWJjJywgJ2RlZicsMSwxMV0sWydjZGUnLCAnZmVmJywyLDIyXSxbJ2VmZycsICdwcXInLDMsMzNdXQpyZXN1bHQgPSBbXQpmb3IgbCBpbiBsc3Q6CglyZXMgPSBbXQoJZm9yIGksIHMgaW4gZW51bWVyYXRlKGwpOgoJCWlmIGlzaW5zdGFuY2Uocywgc3RyKToKCQkJaWYgbGVuKHJlcykgPiAwIGFuZCBpc2luc3RhbmNlKHJlc1tpLTFdLCBzdHIpOgoJCQkJcmVzW2ktMV0gKz0gZiIge3N9IgoJCQllbHNlOgoJCQkJcmVzLmFwcGVuZChzKQoJCWVsc2U6CgkJCXJlcy5hcHBlbmQocykKCXJlc3VsdC5hcHBlbmQocmVzKQoKcHJpbnQocmVzdWx0KQ==
[['abc def', 1, 11], ['cde fef', 2, 22], ['efg pqr', 3, 33]]