You can use a list comprehension to filter the data you need. For example:
# Data:
l=[{"id":"1", "name": "name1"}, {"id":"2", "name": "nam2"}, {"id":"1", "name": "name3"}]
print(len([x for x in l if x['id']=='1'])) # Result: 2
# ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
# This is the key part: you filter the list according to a condition
# (in this case: x['id']=='1').
# If all you need is the number of entries for which the condition
# holds, printing the length of the resulting list will be enough.
solved Is there a way to search an object in a python list?