splice

async def splice(self, destName: str, srcName: str, srcStart: int, srcEnd = None, destPos = None) -> None

Param	Description
destName	The list to receive the spliced nodes. This is created if it doesn't exist.
srcName	The list to splice
srcStart	The position in srcName to begin splicing
srcEnd	The exclusive position in srcName to stop splicing. If None, to end is used
destPos	The position in destName where the spliced nodes will be inserted. If None, nodes be appended to the tail

Move source nodes from [srcStart, srcEnd) to the destination list, inserting at destPos.

If the destination list does not exist, it is created.

No nodes are copied, only pointers are amended.

Raises

• ResponseError if query fails
  • srcName does not exist
• ValueError
  • destName is empty
  • srcName is empty
• TypeError
  • srcEnd not an int
  • destPos not an int

Examples

from ndb.client import NdbClient
from ndb.lists import ObjLists

client = NdbClient()
await client.open('ws://127.0.0.1:1987/')

lists = ObjLists(client)

await lists.create('src')

data = []
for i in range(0,10):
  data.append({f'k{i}':i})

await lists.add('src', data)

src_list = await lists.get_rng('src', start=0)
print(f'Source\n{src_list}')

# move k3, k4 to a new list
print('Splicing 1')
await lists.splice('dest', 'src', srcStart=3, srcEnd=5)

src_list = await lists.get_rng('src', start=0)
dest_list = await lists.get_rng('dest', start=0)

print(f'\tSource: {src_list}')
print(f'\tDest: {dest_list}')

# move k5 to k9, appending to destination
print('Splicing 2')
await lists.splice('dest', 'src', srcStart=3)

src_list = await lists.get_rng('src', start=0)
dest_list = await lists.get_rng('dest', start=0)

print(f'\tSource: {src_list}')
print(f'\tDest: {dest_list}')

Source
[{'k0': 0}, {'k1': 1}, {'k2': 2}, {'k3': 3}, {'k4': 4}, {'k5': 5}, {'k6': 6}, {'k7': 7}, {'k8': 8}, {'k9': 9}]
Splicing 1
  Source: [{'k0': 0}, {'k1': 1}, {'k2': 2}, {'k5': 5}, {'k6': 6}, {'k7': 7}, {'k8': 8}, {'k9': 9}]
  Dest: [{'k3': 3}, {'k4': 4}]
Splicing 2
  Source: [{'k0': 0}, {'k1': 1}, {'k2': 2}]
  Dest: [{'k3': 3}, {'k4': 4}, {'k5': 5}, {'k6': 6}, {'k7': 7}, {'k8': 8}, {'k9': 9}]