我对Flask和Matplotlib很新。我希望能够显示我在某些HTML中生成的简单图表,但我很难弄清楚如何。这是我的Python代码:
from flask import Flask, render_template
import numpy as np
import pandas
import matplotlib.pyplot as plt
app = Flask(__name__)
variables = pandas.read_csv('C:\\path\\to\\variable.csv')
price =variables['price']
@app.route('/test')
def chartTest():
lnprice=np.log(price)
plt.plot(lnprice)
return render_template('untitled1.html', name = plt.show())
if __name__ == '__main__':
app.run(debug = True)
这是我的HTML:
<!doctype html>
<html>
<body>
<h1>Price Chart</h1>
<p>{{ name }}</p>
<img src={{ name }} alt="Chart" height="42" width="42">
</body>
</html>
答案 0 :(得分:23)
您可以在Flask URL路由处理程序中即时生成图像:
import io
import random
from flask import Response
from matplotlib.backends.backend_agg import FigureCanvasAgg as FigureCanvas
from matplotlib.figure import Figure
@app.route('/plot.png')
def plot_png():
fig = create_figure()
output = io.BytesIO()
FigureCanvas(fig).print_png(output)
return Response(output.getvalue(), mimetype='image/png')
def create_figure():
fig = Figure()
axis = fig.add_subplot(1, 1, 1)
xs = range(100)
ys = [random.randint(1, 50) for x in xs]
axis.plot(xs, ys)
return fig
然后您需要在HTML模板中包含图像:
<img src="/plot.png" alt="my plot">
答案 1 :(得分:3)
正如@d parolin指出的那样,matplotlib
生成的数字需要在被HTML呈现之前保存。要通过HTML在flask
中投放图片,您需要将图片存储在flask
文件目录中:
static/
images/
plot.png --> store plots here
templates/
因此,在您的应用中,请使用plt.savefig
:
@app.route('/test')
def chartTest():
lnprice=np.log(price)
plt.plot(lnprice)
plt.savefig('/static/images/new_plot.png')
return render_template('untitled1.html', name = 'new_plot', url ='/static/images/new_plot.png')
然后,在untitled1.html
:
<p>{{ name }}</p>
<img src={{ url}} alt="Chart" height="42" width="42">