Python 实现本地分页

在项目开发的过程中，遇到分页的第一页就展示大量的数据，导致前端列表加载展示的速度慢，所以需要在本地加入分页处理，把所有数据先放到内存里，下面我用Python演示如何实现本地分页的算法（针对二级数据结构）

initialSize = 2 # 首屏展示条数
eachSize = 5    # 剩余页展示条数

local_pages = []  # 本地分页数据

def makePage(d):
    '''
    制作分页数据
    '''
    local_pages.clear()
    if calcSize(d) > initialSize: # 总条数大于首屏数，使用本地分页
        sublist = []
        for item in d:
            for child in item["child"]:
                sublist.append(child)
        
        firstPageSize = min(len(sublist), initialSize) # 第一页的大小

        local_pages.append(sublist[0:firstPageSize]) # 取第一页的集合

        remain_size = len(sublist)-firstPageSize # 剩余条数

        group_count = int(remain_size / eachSize) # 计算分页数

        last_count = remain_size % eachSize # 取余，最后剩余多少条

        idx = 0
        for idx in range(group_count):
            start = firstPageSize + idx * eachSize
            end = start + eachSize
            local_pages.append(sublist[start:end]) # 新增页集合

        if last_count > 0:
            local_pages.append(sublist[-last_count:]) # 余数不为0，将作为最后一页集合
    
    pass
                

def calcSize(d)->int:
    '''
    计算总条数
    '''
    size = 0
    for item in d:
        size += len(item["child"]) + 1
    return size

def printPage():
    '''
    打印页面
    '''
    idx = 0
    for p in local_pages:
        idx += 1
        print("page:{}".format(idx))
        for item in p:
            print(item)


data = [{"id":"1",
         "name":"parent_1",
         "child":[
             {"id":"1_1",
              "name":"RS234326348264",
              "parent_id":"1"
              },
             {"id":"1_2",
              "name":"RS234326348264",
              "parent_id":"1"
              },
             {"id":"1_3",
              "name":"RS234326348264",
              "parent_id":"1"
              },
             {"id":"1_4",
              "name":"RS234326348264",
              "parent_id":"1"
              },
              {"id":"1_5",
              "name":"RS234326348264",
              "parent_id":"1"
              },
              {"id":"1_6",
              "name":"RS234326348264",
              "parent_id":"1"
              },
              {"id":"1_7",
              "name":"RS234326348264",
              "parent_id":"1"
              },
              {"id":"1_8",
              "name":"RS234326348264",
              "parent_id":"1"
              },
              {"id":"1_9",
              "name":"RS234326348264",
              "parent_id":"1"
              }]},

        {"id":"2",
         "name":"parent_2",
         "child":[
              {"id":"2_1",
              "name":"RS234326348264",
              "parent_id":"2"
              }]}]

print(f"首屏展示条数:{initialSize}")
print(f"剩余页展示条数:{eachSize}")
makePage(data)
printPage()

打印结果

首屏展示条数:2
剩余页展示条数:5
page:1
{'id': '1_1', 'name': 'RS234326348264', 'parent_id': '1'}
{'id': '1_2', 'name': 'RS234326348264', 'parent_id': '1'}
page:2
{'id': '1_3', 'name': 'RS234326348264', 'parent_id': '1'}
{'id': '1_4', 'name': 'RS234326348264', 'parent_id': '1'}
{'id': '1_5', 'name': 'RS234326348264', 'parent_id': '1'}
{'id': '1_6', 'name': 'RS234326348264', 'parent_id': '1'}
{'id': '1_7', 'name': 'RS234326348264', 'parent_id': '1'}
page:3
{'id': '1_8', 'name': 'RS234326348264', 'parent_id': '1'}
{'id': '1_9', 'name': 'RS234326348264', 'parent_id': '1'}
{'id': '2_1', 'name': 'RS234326348264', 'parent_id': '2'}