はじめに

Pythonを書く際に、よく使うテクニックやツールについてまとめました。特に、自分が今まで困ってきた内容を中心に取り上げており、自分のためのメモとしても活用しています。

Seaborn

SeabornはPythonで利用可能なデータ可視化ライブラリです。Matplotlibのラッパーライブラリであるため、Matplotlibの機能を利用することができます。Seabornは、データの可視化を行う際に、Matplotlibよりも簡単に利用できるため、データの可視化を行う際には、Seabornをよく利用しています。

データの読み込み

seabornは、sns.load_dataset関数を用いて、データを読み込むことができます。以下のコードを実行することで、tipsデータを読み込むことができます。

import seaborn as sns

df = sns.load_dataset("tips")

データの詳細

	total_bill	tip	sex	smoker	day	time	size
0	16.99	1.01	Female	No	Sun	Dinner	2
1	10.34	1.66	Male	No	Sun	Dinner	3
2	21.01	3.5	Male	No	Sun	Dinner	3
3	23.68	3.31	Male	No	Sun	Dinner	2
4	24.59	3.61	Female	No	Sun	Dinner	4
5	25.29	4.71	Male	No	Sun	Dinner	4
6	8.77	2	Male	No	Sun	Dinner	2
7	26.88	3.12	Male	No	Sun	Dinner	4
8	15.04	1.96	Male	No	Sun	Dinner	2
9	14.78	3.23	Male	No	Sun	Dinner	2
10	10.27	1.71	Male	No	Sun	Dinner	2
11	35.26	5	Female	No	Sun	Dinner	4
12	15.42	1.57	Male	No	Sun	Dinner	2
13	18.43	3	Male	No	Sun	Dinner	4
14	14.83	3.02	Female	No	Sun	Dinner	2
15	21.58	3.92	Male	No	Sun	Dinner	2
16	10.33	1.67	Female	No	Sun	Dinner	3
17	16.29	3.71	Male	No	Sun	Dinner	3
18	16.97	3.5	Female	No	Sun	Dinner	3
19	20.65	3.35	Male	No	Sat	Dinner	3
20	17.92	4.08	Male	No	Sat	Dinner	2
21	20.29	2.75	Female	No	Sat	Dinner	2
22	15.77	2.23	Female	No	Sat	Dinner	2
23	39.42	7.58	Male	No	Sat	Dinner	4
24	19.82	3.18	Male	No	Sat	Dinner	2
25	17.81	2.34	Male	No	Sat	Dinner	4
26	13.37	2	Male	No	Sat	Dinner	2
27	12.69	2	Male	No	Sat	Dinner	2
28	21.7	4.3	Male	No	Sat	Dinner	2
29	19.65	3	Female	No	Sat	Dinner	2
30	9.55	1.45	Male	No	Sat	Dinner	2
31	18.35	2.5	Male	No	Sat	Dinner	4
32	15.06	3	Female	No	Sat	Dinner	2
33	20.69	2.45	Female	No	Sat	Dinner	4
34	17.78	3.27	Male	No	Sat	Dinner	2
35	24.06	3.6	Male	No	Sat	Dinner	3
36	16.31	2	Male	No	Sat	Dinner	3
37	16.93	3.07	Female	No	Sat	Dinner	3
38	18.69	2.31	Male	No	Sat	Dinner	3
39	31.27	5	Male	No	Sat	Dinner	3
40	16.04	2.24	Male	No	Sat	Dinner	3
41	17.46	2.54	Male	No	Sun	Dinner	2
42	13.94	3.06	Male	No	Sun	Dinner	2
43	9.68	1.32	Male	No	Sun	Dinner	2
44	30.4	5.6	Male	No	Sun	Dinner	4
45	18.29	3	Male	No	Sun	Dinner	2
46	22.23	5	Male	No	Sun	Dinner	2
47	32.4	6	Male	No	Sun	Dinner	4
48	28.55	2.05	Male	No	Sun	Dinner	3
49	18.04	3	Male	No	Sun	Dinner	2
50	12.54	2.5	Male	No	Sun	Dinner	2
51	10.29	2.6	Female	No	Sun	Dinner	2
52	34.81	5.2	Female	No	Sun	Dinner	4
53	9.94	1.56	Male	No	Sun	Dinner	2
54	25.56	4.34	Male	No	Sun	Dinner	4
55	19.49	3.51	Male	No	Sun	Dinner	2
56	38.01	3	Male	Yes	Sat	Dinner	4
57	26.41	1.5	Female	No	Sat	Dinner	2
58	11.24	1.76	Male	Yes	Sat	Dinner	2
59	48.27	6.73	Male	No	Sat	Dinner	4
60	20.29	3.21	Male	Yes	Sat	Dinner	2
61	13.81	2	Male	Yes	Sat	Dinner	2
62	11.02	1.98	Male	Yes	Sat	Dinner	2
63	18.29	3.76	Male	Yes	Sat	Dinner	4
64	17.59	2.64	Male	No	Sat	Dinner	3
65	20.08	3.15	Male	No	Sat	Dinner	3
66	16.45	2.47	Female	No	Sat	Dinner	2
67	3.07	1	Female	Yes	Sat	Dinner	1
68	20.23	2.01	Male	No	Sat	Dinner	2
69	15.01	2.09	Male	Yes	Sat	Dinner	2
70	12.02	1.97	Male	No	Sat	Dinner	2
71	17.07	3	Female	No	Sat	Dinner	3
72	26.86	3.14	Female	Yes	Sat	Dinner	2
73	25.28	5	Female	Yes	Sat	Dinner	2
74	14.73	2.2	Female	No	Sat	Dinner	2
75	10.51	1.25	Male	No	Sat	Dinner	2
76	17.92	3.08	Male	Yes	Sat	Dinner	2
77	27.2	4	Male	No	Thur	Lunch	4
78	22.76	3	Male	No	Thur	Lunch	2
79	17.29	2.71	Male	No	Thur	Lunch	2
80	19.44	3	Male	Yes	Thur	Lunch	2
81	16.66	3.4	Male	No	Thur	Lunch	2
82	10.07	1.83	Female	No	Thur	Lunch	1
83	32.68	5	Male	Yes	Thur	Lunch	2
84	15.98	2.03	Male	No	Thur	Lunch	2
85	34.83	5.17	Female	No	Thur	Lunch	4
86	13.03	2	Male	No	Thur	Lunch	2
87	18.28	4	Male	No	Thur	Lunch	2
88	24.71	5.85	Male	No	Thur	Lunch	2
89	21.16	3	Male	No	Thur	Lunch	2
90	28.97	3	Male	Yes	Fri	Dinner	2
91	22.49	3.5	Male	No	Fri	Dinner	2
92	5.75	1	Female	Yes	Fri	Dinner	2
93	16.32	4.3	Female	Yes	Fri	Dinner	2
94	22.75	3.25	Female	No	Fri	Dinner	2
95	40.17	4.73	Male	Yes	Fri	Dinner	4
96	27.28	4	Male	Yes	Fri	Dinner	2
97	12.03	1.5	Male	Yes	Fri	Dinner	2
98	21.01	3	Male	Yes	Fri	Dinner	2
99	12.46	1.5	Male	No	Fri	Dinner	2
100	11.35	2.5	Female	Yes	Fri	Dinner	2
101	15.38	3	Female	Yes	Fri	Dinner	2
102	44.3	2.5	Female	Yes	Sat	Dinner	3
103	22.42	3.48	Female	Yes	Sat	Dinner	2
104	20.92	4.08	Female	No	Sat	Dinner	2
105	15.36	1.64	Male	Yes	Sat	Dinner	2
106	20.49	4.06	Male	Yes	Sat	Dinner	2
107	25.21	4.29	Male	Yes	Sat	Dinner	2
108	18.24	3.76	Male	No	Sat	Dinner	2
109	14.31	4	Female	Yes	Sat	Dinner	2
110	14	3	Male	No	Sat	Dinner	2
111	7.25	1	Female	No	Sat	Dinner	1
112	38.07	4	Male	No	Sun	Dinner	3
113	23.95	2.55	Male	No	Sun	Dinner	2
114	25.71	4	Female	No	Sun	Dinner	3
115	17.31	3.5	Female	No	Sun	Dinner	2
116	29.93	5.07	Male	No	Sun	Dinner	4
117	10.65	1.5	Female	No	Thur	Lunch	2
118	12.43	1.8	Female	No	Thur	Lunch	2
119	24.08	2.92	Female	No	Thur	Lunch	4
120	11.69	2.31	Male	No	Thur	Lunch	2
121	13.42	1.68	Female	No	Thur	Lunch	2
122	14.26	2.5	Male	No	Thur	Lunch	2
123	15.95	2	Male	No	Thur	Lunch	2
124	12.48	2.52	Female	No	Thur	Lunch	2
125	29.8	4.2	Female	No	Thur	Lunch	6
126	8.52	1.48	Male	No	Thur	Lunch	2
127	14.52	2	Female	No	Thur	Lunch	2
128	11.38	2	Female	No	Thur	Lunch	2
129	22.82	2.18	Male	No	Thur	Lunch	3
130	19.08	1.5	Male	No	Thur	Lunch	2
131	20.27	2.83	Female	No	Thur	Lunch	2
132	11.17	1.5	Female	No	Thur	Lunch	2
133	12.26	2	Female	No	Thur	Lunch	2
134	18.26	3.25	Female	No	Thur	Lunch	2
135	8.51	1.25	Female	No	Thur	Lunch	2
136	10.33	2	Female	No	Thur	Lunch	2
137	14.15	2	Female	No	Thur	Lunch	2
138	16	2	Male	Yes	Thur	Lunch	2
139	13.16	2.75	Female	No	Thur	Lunch	2
140	17.47	3.5	Female	No	Thur	Lunch	2
141	34.3	6.7	Male	No	Thur	Lunch	6
142	41.19	5	Male	No	Thur	Lunch	5
143	27.05	5	Female	No	Thur	Lunch	6
144	16.43	2.3	Female	No	Thur	Lunch	2
145	8.35	1.5	Female	No	Thur	Lunch	2
146	18.64	1.36	Female	No	Thur	Lunch	3
147	11.87	1.63	Female	No	Thur	Lunch	2
148	9.78	1.73	Male	No	Thur	Lunch	2
149	7.51	2	Male	No	Thur	Lunch	2
150	14.07	2.5	Male	No	Sun	Dinner	2
151	13.13	2	Male	No	Sun	Dinner	2
152	17.26	2.74	Male	No	Sun	Dinner	3
153	24.55	2	Male	No	Sun	Dinner	4
154	19.77	2	Male	No	Sun	Dinner	4
155	29.85	5.14	Female	No	Sun	Dinner	5
156	48.17	5	Male	No	Sun	Dinner	6
157	25	3.75	Female	No	Sun	Dinner	4
158	13.39	2.61	Female	No	Sun	Dinner	2
159	16.49	2	Male	No	Sun	Dinner	4
160	21.5	3.5	Male	No	Sun	Dinner	4
161	12.66	2.5	Male	No	Sun	Dinner	2
162	16.21	2	Female	No	Sun	Dinner	3
163	13.81	2	Male	No	Sun	Dinner	2
164	17.51	3	Female	Yes	Sun	Dinner	2
165	24.52	3.48	Male	No	Sun	Dinner	3
166	20.76	2.24	Male	No	Sun	Dinner	2
167	31.71	4.5	Male	No	Sun	Dinner	4
168	10.59	1.61	Female	Yes	Sat	Dinner	2
169	10.63	2	Female	Yes	Sat	Dinner	2
170	50.81	10	Male	Yes	Sat	Dinner	3
171	15.81	3.16	Male	Yes	Sat	Dinner	2
172	7.25	5.15	Male	Yes	Sun	Dinner	2
173	31.85	3.18	Male	Yes	Sun	Dinner	2
174	16.82	4	Male	Yes	Sun	Dinner	2
175	32.9	3.11	Male	Yes	Sun	Dinner	2
176	17.89	2	Male	Yes	Sun	Dinner	2
177	14.48	2	Male	Yes	Sun	Dinner	2
178	9.6	4	Female	Yes	Sun	Dinner	2
179	34.63	3.55	Male	Yes	Sun	Dinner	2
180	34.65	3.68	Male	Yes	Sun	Dinner	4
181	23.33	5.65	Male	Yes	Sun	Dinner	2
182	45.35	3.5	Male	Yes	Sun	Dinner	3
183	23.17	6.5	Male	Yes	Sun	Dinner	4
184	40.55	3	Male	Yes	Sun	Dinner	2
185	20.69	5	Male	No	Sun	Dinner	5
186	20.9	3.5	Female	Yes	Sun	Dinner	3
187	30.46	2	Male	Yes	Sun	Dinner	5
188	18.15	3.5	Female	Yes	Sun	Dinner	3
189	23.1	4	Male	Yes	Sun	Dinner	3
190	15.69	1.5	Male	Yes	Sun	Dinner	2
191	19.81	4.19	Female	Yes	Thur	Lunch	2
192	28.44	2.56	Male	Yes	Thur	Lunch	2
193	15.48	2.02	Male	Yes	Thur	Lunch	2
194	16.58	4	Male	Yes	Thur	Lunch	2
195	7.56	1.44	Male	No	Thur	Lunch	2
196	10.34	2	Male	Yes	Thur	Lunch	2
197	43.11	5	Female	Yes	Thur	Lunch	4
198	13	2	Female	Yes	Thur	Lunch	2
199	13.51	2	Male	Yes	Thur	Lunch	2
200	18.71	4	Male	Yes	Thur	Lunch	3
201	12.74	2.01	Female	Yes	Thur	Lunch	2
202	13	2	Female	Yes	Thur	Lunch	2
203	16.4	2.5	Female	Yes	Thur	Lunch	2
204	20.53	4	Male	Yes	Thur	Lunch	4
205	16.47	3.23	Female	Yes	Thur	Lunch	3
206	26.59	3.41	Male	Yes	Sat	Dinner	3
207	38.73	3	Male	Yes	Sat	Dinner	4
208	24.27	2.03	Male	Yes	Sat	Dinner	2
209	12.76	2.23	Female	Yes	Sat	Dinner	2
210	30.06	2	Male	Yes	Sat	Dinner	3
211	25.89	5.16	Male	Yes	Sat	Dinner	4
212	48.33	9	Male	No	Sat	Dinner	4
213	13.27	2.5	Female	Yes	Sat	Dinner	2
214	28.17	6.5	Female	Yes	Sat	Dinner	3
215	12.9	1.1	Female	Yes	Sat	Dinner	2
216	28.15	3	Male	Yes	Sat	Dinner	5
217	11.59	1.5	Male	Yes	Sat	Dinner	2
218	7.74	1.44	Male	Yes	Sat	Dinner	2
219	30.14	3.09	Female	Yes	Sat	Dinner	4
220	12.16	2.2	Male	Yes	Fri	Lunch	2
221	13.42	3.48	Female	Yes	Fri	Lunch	2
222	8.58	1.92	Male	Yes	Fri	Lunch	1
223	15.98	3	Female	No	Fri	Lunch	3
224	13.42	1.58	Male	Yes	Fri	Lunch	2
225	16.27	2.5	Female	Yes	Fri	Lunch	2
226	10.09	2	Female	Yes	Fri	Lunch	2
227	20.45	3	Male	No	Sat	Dinner	4
228	13.28	2.72	Male	No	Sat	Dinner	2
229	22.12	2.88	Female	Yes	Sat	Dinner	2
230	24.01	2	Male	Yes	Sat	Dinner	4
231	15.69	3	Male	Yes	Sat	Dinner	3
232	11.61	3.39	Male	No	Sat	Dinner	2
233	10.77	1.47	Male	No	Sat	Dinner	2
234	15.53	3	Male	Yes	Sat	Dinner	2
235	10.07	1.25	Male	No	Sat	Dinner	2
236	12.6	1	Male	Yes	Sat	Dinner	2
237	32.83	1.17	Male	Yes	Sat	Dinner	2
238	35.83	4.67	Female	No	Sat	Dinner	3
239	29.03	5.92	Male	No	Sat	Dinner	3
240	27.18	2	Female	Yes	Sat	Dinner	2
241	22.67	2	Male	Yes	Sat	Dinner	2
242	17.82	1.75	Male	No	Sat	Dinner	2
243	18.78	3	Female	No	Thur	Dinner	2

他にも、アヤメのデータirixや、タイタニックのデータtitanicなどがあります。
使用可能なデータセットは、sns.get_dataset_names()で確認できます。

catplotの使い方

catplotとは、洗練された可視化を短いコードで実現可能な関数です。
kindでグラフの種類を指定可能であり、散布図"strip"、箱ひげ図"box"、バイオリンプロット"violin"、棒グラフ"bar"、ポイントプロット"point"、カウントプロット"count"があります。

import seaborn as sns

df = sns.load_dataset("diamonds")

g = sns.catplot(
    data=df,         # データセットを指定
    kind="bar",      # グラフの種類を選択
    x="cut",         # X軸に"cut"を設定
    y="carat",       # Y軸に"carat"を設定
    hue="color",     # "color"に基づいて色分け
    col="clarity",   # "clarity"に基づいて列を分ける
    col_wrap=4,      # 一行あたりの列数を4に設定
    height=3,        # 各グラフの高さ
    aspect=1.0,      # 各グラフのアスペクト比 (大きいほど横長)
    errwidth=1.2,    # エラーバーの太さ
    # palette="Set2",  # カラーパレット（デフォルトが良いのでコメントアウト）
)
g.tick_params(axis="x", rotation=30)

凡例の位置を変更する方法

凡例はデフォルトで、グラフの右側に表示される。位置を変更したい時は、sns.move_legendを用いる。

sns.move_legend(
  obj=g,                        # g = sns.catplot()の戻り値
  loc="upper center",           # 凡例の位置を指定
  ncol=7,                       # 凡例の列数
  bbox_to_anchor=(0.51, 1.22),  # 凡例の位置を調整
  fontsize=14.5,                # 凡例のフォントサイズ
  frameon=True,                 # 凡例の枠線を表示
  columnspacing=0.5             # 凡例の列間のスペース
)

保存したpdfに凡例が表示されない時の対処法

グラフをg.fig.savefig()で保存した際に、凡例が表示されないことがある。その場合は、bbox_inches="tight"を追加する。

g.fig.savefig("name.pdf", bbox_inches="tight")

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