1 2 3 # Initialize Otter import otter grader = otter.Notebook("lab03.ipynb") Lab 3: Data Cleaning and EDA In this lab you will be working on visualizing a dataset from the City of Berkeley containing data on calls to the Berkeley Police Department. Information about the dataset can be found at this link. Content Warning This lab includes an analysis of crime in Berkeley. If you feel uncomfortable with this topic, please contact your GSI or the instructors.

1 2 3 # Initialize Otter import otter grader = otter.Notebook("lab04.ipynb") Lab 4: Visualization, Transformations, and KDEs Objective In this lab you will get some practice plotting, applying data transformations, and working with kernel density estimators (KDEs). We will be working with data from the World Bank containing various statistics for countries and territories around the world. 1 2 3 4 5 6 7 8 9 10 import pandas as pd import numpy as np import seaborn as sns import matplotlib.

Index 竟然是一种数据结构？ search and insertion in ISAM indexed sequential access method 注意建立了许多索引，沿用BST的思想，但是insert的时候会出现overflow pages （IBM in 1960s） B+ Tree 和B Tree的区别在于：B+只有叶子存放数据，而B Tree的中间节点也存放数据。 几乎和上面一样，但是多了 dynamic tree index always balanced support efficient insertions and deletions grows at root not leaves 注意: 占有率：几乎半满，除了root 底部DLL $max\ fan\ out = 2d + 1$ 工业实际情况 🤔 B+ Tree Operations search, 同上 insert 没有overflow，直接插入 满了，分裂成两个节点，中间节点存放 中间key（过程中可能是右边最小的那个key），左右节点存放左右key 递归向上分裂，直到根节点 叶子 $\xrightarrow{copy}$ 父节点 ，父节点 $\xrightarrow{push}$ 新父节点 delete 😉 bulk loading 批量加载 精髓在于先排序，后构建 time-stamp: 01h09min02s