{ "cells": [ { "cell_type": "code", "execution_count": 1, "metadata": {}, "outputs": [], "source": [ "import pandas as pd\n", "import numpy as np" ] }, { "cell_type": "code", "execution_count": 2, "metadata": {}, "outputs": [], "source": [ "data = pd.read_csv('table.csv',index_col='ID')" ] }, { "cell_type": "code", "execution_count": 3, "metadata": {}, "outputs": [ { "data": { "text/html": [ "
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SchoolClassGenderAddressHeightWeightMathPhysics
ID
1101S_1C_1Mstreet_11736334.0A+
1102S_1C_1Fstreet_21927332.5B+
1103S_1C_1Mstreet_21868287.2B+
1104S_1C_1Fstreet_21678180.4B-
1105S_1C_1Fstreet_41596484.8B+
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" ], "text/plain": [ " School Class Gender Address Height Weight Math Physics\n", "ID \n", "1101 S_1 C_1 M street_1 173 63 34.0 A+\n", "1102 S_1 C_1 F street_2 192 73 32.5 B+\n", "1103 S_1 C_1 M street_2 186 82 87.2 B+\n", "1104 S_1 C_1 F street_2 167 81 80.4 B-\n", "1105 S_1 C_1 F street_4 159 64 84.8 B+" ] }, "execution_count": 3, "metadata": {}, "output_type": "execute_result" } ], "source": [ "data.head()" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "# 思考题" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "1. 将物理成绩（'Physics'）从 object 类型转化为类别类型 Categorical，并且定义其顺序，列出每个分数（按降序排列）有多少学生，以及每个物理分数对应的同学的数学成绩的平均值。" ] }, { "cell_type": "code", "execution_count": 4, "metadata": {}, "outputs": [], "source": [ "data['Physics'] = pd.Categorical(data['Physics'],categories=['C','B-','B','B+','A-','A','A+'], ordered=True)" ] }, { "cell_type": "code", "execution_count": 5, "metadata": {}, "outputs": [ { "data": { "text/plain": [ "Physics\n", "A+ 3\n", "A 4\n", "A- 3\n", "B+ 9\n", "B 8\n", "B- 6\n", "C 2\n", "dtype: int64" ] }, "execution_count": 5, "metadata": {}, "output_type": "execute_result" } ], "source": [ "data.value_counts('Physics').sort_index(ascending=False)" ] }, { "cell_type": "code", "execution_count": 6, "metadata": {}, "outputs": [ { "data": { "text/plain": [ "Physics\n", "C 74.600000\n", "B- 62.283333\n", "B 52.612500\n", "B+ 62.144444\n", "A- 93.400000\n", "A 49.350000\n", "A+ 55.533333\n", "Name: Math, dtype: float64" ] }, "execution_count": 6, "metadata": {}, "output_type": "execute_result" } ], "source": [ "data.groupby('Physics')['Math'].mean().sort_index()" ] }, { "cell_type": "markdown", "metadata": {}, "source": [ "2. 将数学成绩（'Math'）按照分数段 0-40，40-50，50-60，60-70，70-80，80-90，90-100 （左开右闭区间） 转换成 'A+','A','A-','B+','B','B-','C' 的类别数据。列出每个分数（按升序排列）有多少学生。找出数学和物理都得 A 的学生。" ] }, { "cell_type": "code", "execution_count": 7, "metadata": {}, "outputs": [], "source": [ "bins = [0,40,50,60,70,80,90,100]\n", "cuts = pd.cut(data['Math'],bins=bins,labels=['C','B-','B','B+','A-','A','A+'])\n", "data['Math'] = pd.Categorical(cuts,categories=['C','B-','B','B+','A-','A','A+'], ordered=True)" ] }, { "cell_type": "code", "execution_count": 8, "metadata": {}, "outputs": [ { "data": { "text/plain": [ "Math\n", "C 7\n", "B- 6\n", "B 4\n", "B+ 6\n", "A- 3\n", "A 7\n", "A+ 2\n", "dtype: int64" ] }, "execution_count": 8, "metadata": {}, "output_type": "execute_result" } ], "source": [ "data.value_counts('Math').sort_index(ascending=True)" ] }, { "cell_type": "code", "execution_count": 9, "metadata": {}, "outputs": [ { "data": { "text/html": [ "
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SchoolClassGenderAddressHeightWeightMathPhysics
ID
1304S_1C_3Mstreet_219570AA
\n", "
" ], "text/plain": [ " School Class Gender Address Height Weight Math Physics\n", "ID \n", "1304 S_1 C_3 M street_2 195 70 A A" ] }, "execution_count": 9, "metadata": {}, "output_type": "execute_result" } ], "source": [ "data[(data.Math=='A') & (data.Physics=='A')]" ] }, { "cell_type": "code", "execution_count": null, "metadata": {}, "outputs": [], "source": [] } ], "metadata": { "kernelspec": { "display_name": "Python 3", "language": "python", "name": "python3" }, "language_info": { "codemirror_mode": { "name": "ipython", "version": 3 }, "file_extension": ".py", "mimetype": "text/x-python", "name": "python", "nbconvert_exporter": "python", "pygments_lexer": "ipython3", "version": "3.8.5" } }, "nbformat": 4, "nbformat_minor": 4 }