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本项目主要是利用Python的数据分析相关库对于白酒数据集进行分析,数据集的主要来源是
Wine Quality Data-数据集-阿里云天池tianchi.aliyun.com导入数据分析所需要的库:
- %matplotlib inline
- import pandas as pd
- import numpy as np
- import seaborn as sns
- import matplotlib.pyplot as plt
-
- color = sns.color_palette()
- pd.set_option('precision', 3)
读取数据:
df = pd.read_csv(r"winequality-white.csv",sep = ';')
df.head(10)
df.info()
df.describe()
- df['quality'].describe()
-
- #了解一下质量评分的描述性统计的情况
品质评分的范围是0-10, 该数据集的评分范围是3-9。
- print(df.isnull().sum())
-
- #可以看出这个数据集没有空值
- # set plot style
- plt.style.use('ggplot')
-
- #对于每个特征变量画出箱型图
- colnm = df.columns.tolist()
- fig = plt.figure(figsize = (10, 6))
-
- for i in range(12):
- plt.subplot(2,6, i+1)
- sns.boxplot(df[colnm[i]], orient='v', width = 0.5, color = color[0])
- plt.ylabel(colnm[i], fontsize = 12)
-
- plt.tight_layout()
- print("nFigure 1 :Univariate Boxplots")
- #对每个特征变量画出直方图
- colnm = df.columns.tolist()
- plt.figure(figsize = (10, 8))
-
- for i in range(12):
- plt.subplot(4, 3, i+1)
- df[colnm[i]].hist(bins = 100, color = color[0])
- plt.xlabel(colnm[i], fontsize = 12)
- plt.ylabel('Frequency')
- plt.tight_layout()
- print('nFigure 2 :Univariate Histograms')
本数据集主要是用来研究白酒的品质和理化性质之间的关系,并建立模型预测白酒品质评分的准确率。品质的评价范围是0-10, 这个数据集主要范围是3到9。
本数据集有7各酸度相关的特征:fixed acidity, volatile acidity, citric acid, free sulfur dioxide, total sulfur dioxide, sulphates,pH。前6个特征都与红酒的pH相关。 pH是对数的尺度,所以对前6个特征取对数然后做histogram。另外,pH值主要是与fixed acidity有关,fixed acidity比volatile acidity和citric acid高1到2个数量级(Figure 4),比free sulfur dioxide, total sulfur dioxide, sulphates高3个数量级。一个新特征total acid来自于前三个特征的和。
- acidityFeat = ['fixed acidity', 'volatile acidity', 'citric acid',
- 'free sulfur dioxide', 'total sulfur dioxide', 'sulphates']
-
- plt.figure(figsize = (10, 4))
-
- for i in range(6):
- ax = plt.subplot(2,3,i + 1)
- v = np.log10(np.clip(df[acidityFeature[i]].values, a_min = 0.001,
- a_max = None))
- plt.hist(v, bins = 50, color = color[0])
-
- plt.xlabel('log(' + acidityFeat[i] + ')', fontsize = 12)
- plt.ylabel('Frequency')
- plt.tight_layout()
- print('nFigure 3: Acidity Features in log10 Scale')
- plt.figure(figsize = (6,3))
-
- bins = 10 ** (np.linspace(-2, 2))
- plt.hist(df['fixed acidity'], bins = bins, edgecolor = 'k', label =
- 'Fixed Acidity')
- plt.hist(df['volatile acidity'], bins = bins, edgecolor = 'k', label =
- 'Volatile Acidity')
- plt.hist(df['citric acid'], bins = bins, edgecolor = 'k', alpha = 0.8,
- label = 'Citric Acid')
- plt.xscale('log')
- plt.xlabel('Acid Concentration (g/dm^3)')
- plt.ylabel('Frequency')
- plt.title('Histogram of Acid Concentration')
- plt.legend()
- plt.tight_layout()
-
- print('Figure 4')
- #总酸度
- df['total acid'] = df['fixed acidity'] + df['volatile acidity'] + df['citric acid']
-
- plt.figure(figsize = (8, 3))
-
- plt.subplot(121)
- plt.hist(df['total acid'], bins = 50, color = color[0])
- plt.xlabel('total acid')
- plt.ylabel('Frequency')
- plt.subplot(222)
- plt.hist(np.log(df['total acid']), bins = 50, color = color[0])
- plt.xlabel('log(total acid)')
- plt.ylabel('Frequency')
- plt.tight_layout()
-
- print("Figure 5: Total Acid Histogram")
白酒的甜并不是糖类的甜。白酒的甜味和糖形成的甜味有差别,属甘甜兼有醇厚感和绵柔感,在品尝时常常在呈味感中来得比较迟,呈后味,称“回甜”。干红(<=4 g/L), 半干(4-12 g/L),半甜(12-45 g/L),和甜(>45 g/L)。
- df['sweetness'] = pd.cut(df['residual sugar'], bins = [0, 4, 12, 45],
- labels=["dry", "medium dry", "semi-sweet"])
-
- plt.figure(figsize = (5,3))
- df['sweetness'].value_counts().plot(kind = 'bar', color = color[0])
- plt.xticks(rotation=0)
- plt.xlabel('sweetness', fontsize = 12)
- plt.ylabel('Frequency', fontsize = 12)
- plt.tight_layout()
- print("Figure 6: Sweetness")
可以看出大部分的红酒的甜度都不是很高。
白酒和理化性质的关系
- sns.set_style('ticks')
- sns.set_context("notebook", font_scale=1.1)
-
- colnm = df.columns.tolist()[:11] + ['total acid']
- plt.figure(figsize = (10, 8))
-
- for i in range(12):
- plt.subplot(4,3,i + 1)
- sns.boxplot(x = 'quality', y = colnm[i], data = df, color = color[1], width = 0.6)
- plt.ylabel(colnm[i], fontsize = 12)
- plt.tight_layout()
- print("nFigure 7: Physicochemical Properties and Wine Quality by Boxplot")
品质好的酒有更高的PH和酒精度数,更低的挥发性酸、密度、硫酸盐。 其中酒精度数和品质的相关性更高。 柠檬酸、残留糖分、氯离子、二氧化硫似乎对酒的品质影响不大。
画出相关性分析图
- sns.set_style("dark")
-
- plt.figure(figsize = (10,8))
- colnm = df.columns.tolist()[:11] + ['total acid', 'quality']
- mcorr = df[colnm].corr()
- mask = np.zeros_like(mcorr, dtype=np.bool)
- mask[np.triu_indices_from(mask)] = True
- cmap = sns.diverging_palette(220, 10, as_cmap=True)
- g = sns.heatmap(mcorr, mask=mask, cmap=cmap, square=True, annot=True,
- fmt='0.2f')
- print("nFigure 8: Pairwise Correlation Plot")
密度和酒精浓度
- sns.set_style('ticks')
- sns.set_context("notebook", font_scale = 1.4)
-
- plt.figure(figsize = (6,4))
- sns.regplot(x = 'density', y = 'alcohol', data = df, scatter_kws = {
- 's':10
- }, color = color[1])
- plt.xlim(0.986,1.040)
- plt.ylim(6.5,16)
- print("nFigure 9: Desity vs Alcohol")
酸性物质和pH
pH和非挥发性酸性物质有-0.43的相关性。因为非挥发性酸性物质的含量远远高于其他酸性物质,总酸性物质(total acidity)这个特征并没有太多意义。
- acidity_related = ['fixed acidity', 'volatile acidity', 'total sulfur dioxide',
- 'sulphates', 'total acid']
-
- plt.figure(figsize = (10, 6))
-
- for i in range(5):
- plt.subplot(2,3,i + 1)
- sns.regplot(x='pH', y = acidity_related[i], data = df, scatter_kws = {
- 's':10
- }, color = color[1])
- plt.tight_layout()
- print("Figure 10: pH vs acid")
与品质相关性最高的三个特征是酒精浓度、挥发性酸度和pH
- #酒精浓度、挥发性酸度和品质
- plt.style.use('ggplot')
-
- sns.lmplot(x = 'alcohol', y = 'volatile acidity', hue = 'quality',
- data = df, fit_reg = False, scatter_kws={'s':10},
- height = 5)
- print("Figure 11-1:Scatter Plots of Alcohol, Volatile Acid and Quality")
- sns.lmplot(x = 'alcohol', y = 'volatile acidity', col='quality', hue=
- 'quality',
- data = df, fit_reg = False, height = 3, aspect = 0.9, col_wrap=3,
- scatter_kws={'s':20})
- print("Figure 11-2: Scatter Plots of Alcohol, Volatile Acid and Quality")
pH,非挥发性酸和柠檬酸
- #pH和非挥发性酸以及柠檬酸有相关性。整体趋势是浓度越高,pH越低。
- sns.set_style('ticks')
- sns.set_context("notebook", font_scale = 1.4)
-
- plt.figure(figsize = (6,5))
- cm = plt.cm.get_cmap('RdBu')
- sc = plt.scatter(df['fixed acidity'],df['citric acid'],c=df['pH'],
- vmin=2.6, vmax=4, s=15, cmap=cm)
- bar = plt.colorbar(sc)
- bar.set_label('pH', rotation = 0)
- plt.xlabel('fixed acidity')
- plt.ylabel('ctric acid')
- plt.xlim(4,18)
- plt.ylim(0,1)
- print('Figure 12: pH with Fixed Acidity and Citric Acid')
整体来说,白酒的品质主要与酒精浓度、挥发性酸和pH有关。对于品质优于8,或者劣于4的酒,直观上是线性可分的。但是品质为5,6,7的酒很难线性区分。
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