python - 我的条形图没有出现在屏幕上。我该如何解决？

Question

我正在尝试自学如何使用 matplotlib（在 Web 应用程序中）绘制条形图，其中 x 轴将具有各种癌症药物副作用，而 y 轴将具有每个这些副作用的发生百分比副作用。在 Web 应用程序的索引页面上，我有一个选择菜单，我要求用户从“下拉列表”中选择一种癌症。选择“乳腺癌”并单击“提交”（我已经为其创建了一个 html 文件）后，我希望上面讨论的条形图会出现在屏幕上。但是，我的屏幕上根本没有显示条形图。我究竟做错了什么？

这是python代码：

import os
import matplotlib.pyplot as plt
import numpy as np
np.random.seed()
from matplotlib.ticker import FuncFormatter

from cs50 import SQL
from flask import Flask, flash, jsonify, redirect, render_template, 
request, session
from flask_session import Session
from tempfile import mkdtemp
from werkzeug.exceptions import default_exceptions, HTTPException, 
InternalServerError
import sqlite3


app = Flask(__name__)

app.config["TEMPLATES_AUTO_RELOAD"] = True

app.config["SESSION_FILE_DIR"] = mkdtemp()
app.config["SESSION_PERMANENT"] = False
app.config["SESSION_TYPE"] = "filesystem"
Session(app)

db = SQL("sqlite:///cancermeds.db")

@app.route("/", methods=["GET", "POST"])
def index():
    if request.method=="POST":
        selection = request.form.get("cancerlist")
        if selection == "breast cancer":
            #db.execute used to extract info I will use to make 
            #list of keys (for x-axis) and list of values(for y- 
            #axis). Info extracted from table in SQLite3 database. 
            rows = db.execute("SELECT * FROM 'breast cancer'")
            for row in rows:
                keys = list(row.keys())
                del keys[16:19]
                print(keys)
                values = list(row.values())
                del values[16:19]
                print(values)

                fig = plt.figure(figsize=(7,6))
                plt.bar(keys, values, width=0.5)
                plt.xlabel("Side Effects")
                plt.ylabel("Percentages of Occurence of Side 
    Effects")
                plt.title("Bar Chart showing Side Effects of Breast 
Cancer Medication(s) With Their Corrresponding Percentages Of 
Occurence")
                plt.legend()
                plt.show()

        return render_template("breastcancer.html")

    else:
        return render_template("index.html")


if __name__ == '__main__':
    app.run(debug=True)  

这是我终端中的所有内容：

~/environment/justforme/ $ 
~/environment/justforme/ $ FLAKS RUN
bash: FLAKS: command not found
~/environment/justforme/ $ flask run
 * Serving Flask app "application.py" (lazy loading)
 * Environment: development
 * Debug mode: off
 * Running on https://808d061b-7cdd-4348-ab06-3ede74c26f12- 
ide.cs50.xyz:8080/ (Press CTRL+C to quit)
 * Restarting with stat
INFO:werkzeug:192.168.133.245 - - [03/Aug/2019 19:13:30] "GET / 
HTTP/1.0" 200 -
INFO:werkzeug:192.168.133.245 - - [03/Aug/2019 19:13:30] "GET 
/static/styles.css HTTP/1.0" 404 -
DEBUG:cs50:SELECT * FROM 'breast cancer'
['diarrhea %', 'neutropenia %', 'nausea %', 'abdominal pain %', 
'infections %', 'fatigue %', 'anemia %', 'leukopenia %', 'decreased 
appetite %', 'vomiting %', 'headache %', 'alopecia %', 
'thrombocytopenia %', 'peripheral neuropathy %', 'hepatotoxicity 
%', 'cardiac side effects %']
[86, 41, 39, 29, 39, 40, 28, 21, 24, 28, 20, 16, 16, 0, 1, 0]
WARNING:matplotlib.legend:No handles with labels found to put in 
legend.
['diarrhea %', 'neutropenia %', 'nausea %', 'abdominal pain %', 
'infections %', 'fatigue %', 'anemia %', 'leukopenia %', 'decreased 
appetite %', 'vomiting %', 'headache %', 'alopecia %', 
'thrombocytopenia %', 'peripheral neuropathy %', 'hepatotoxicity 
%', 'cardiac side effects %']
[27, 85, 30, 0, 24, 59, 33, 0, 36, 36, 14, 50, 68, 48, 36, 3]
WARNING:matplotlib.legend:No handles with labels found to put in 
legend.
['diarrhea %', 'neutropenia %', 'nausea %', 'abdominal pain %', 
'infections %', 'fatigue %', 'anemia %', 'leukopenia %', 'decreased 
appetite %', 'vomiting %', 'headache %', 'alopecia %', 
'thrombocytopenia %', 'peripheral neuropathy %', 'hepatotoxicity 
%', 'cardiac side effects %']
[24, 8, 40, 19, 10, 50, 14, 1, 0, 19, 28, 0, 31, 32, 0.3, 1.8]
WARNING:matplotlib.legend:No handles with labels found to put in 
legend.
INFO:werkzeug:192.168.133.245 - - [03/Aug/2019 19:13:34] "POST / 
HTTP/1.0" 200 -
INFO:werkzeug:192.168.133.245 - - [03/Aug/2019 19:13:34] "GET 
/static/styles.css HTTP/1.0" 404 -

作为初学者，请原谅我犯的任何可能非常基本的错误。谢谢！

标签： pythonmatplotlibbar-chart

Answer 1

将绘图保存在文件中并<img src="/static/image.png">在 HTML 中使用以显示它的最小示例。

from flask import Flask
import matplotlib.pyplot as plt
import os

app = Flask(__name__)

@app.route('/')
def index():
    keys = [1,2,3,4]
    values = [1,4,2,3]

    plt.bar(keys, values, width=0.5)

    plt.xlabel("Side Effects")
    plt.ylabel("Percentages of Occurence of Side Effects")
    plt.title("Bar Chart showing Side Effects of Breast \
Cancer Medication(s) With Their Corrresponding Percentages Of \
Occurence")
    #plt.legend()

    if not os.path.exists('static'):
        os.makedirs('static')
    plt.savefig('static/image.png')

    return '''<DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<body><img src="/static/image.png"></body>
</html>'''

if __name__ == '__main__':
    app.run()

---

使用mpld3生成交互式绘图的最小示例。

一开始它只有工具：home(reset)、move、resize。

from flask import Flask
import matplotlib.pyplot as plt
import mpld3

app = Flask(__name__)

@app.route('/')
def index():
    keys = [1,2,3,4]
    values = [1,4,2,3]

    ax = plt.bar(keys, values, width=0.5)

    plt.xlabel("Side Effects")
    plt.ylabel("Percentages of Occurence of Side Effects")
    plt.title("Bar Chart showing Side Effects of Breast \
Cancer Medication(s) With Their Corrresponding Percentages Of \
Occurence")
    #plt.legend()

    fig = ax[0].figure

    plt_html = mpld3.fig_to_html(fig)

    return '''<DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<body>''' + plt_html + '''</body>
</html>'''

if __name__ == '__main__':
    app.run()

---

使用seaborn 的最小示例，但它会创建静态图像。

from flask import Flask
import matplotlib.pyplot as plt
import seaborn as sns
import os


app = Flask(__name__)


@app.route('/')
def index():
    keys = [1,2,3,4]
    values = [1,4,2,3]

    sns.barplot(keys, values)

    plt.xlabel("Side Effects")
    plt.ylabel("Percentages of Occurence of Side Effects")
    plt.title("Bar Chart showing Side Effects of Breast \
Cancer Medication(s) With Their Corrresponding Percentages Of \
Occurence")
    #plt.legend()

    if not os.path.exists('static'):
        os.makedirs('static')

    plt.savefig('static/image.png')

    return '''<DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
</head>
<body><img src="/static/image.png"></body>
</html>'''


if __name__ == '__main__':
    app.run()