import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
from matplotlib.collections import LineCollection
from matplotlib.colors import ListedColormap, BoundaryNorm
df = pd.read_excel("C:/Users/AmeliaB/Documents/Python/8-5in_plotting.xlsx", header=0)
df['DATETIME'] = pd.to_datetime(df.DATETIME)
# define variables
y = np.array(df["DHT001_Accel_Axial_Z_Max"])
x = np.array(df["Hole_Depth"])
# Create a set of line segments so we can color them individually
# This creates the points as a N x 1 x 2 array so that we can stack points
# together easily to get the segments. The segments array for line collection
# needs to be (numlines) x (points per line) x 2 (for x and y)
points = np.array([x, y]).T.reshape(-1, 1, 2)
segments = np.concatenate([points[:-1], points[1:]], axis=1)
fig, ax = plt.subplots(1)
cmap = ListedColormap(['green', 'orange', 'red', "maroon"])
norm = BoundaryNorm([1, 1.5, 2.5, 5, 5.5], cmap.N)
lc = LineCollection(segments, cmap=cmap, norm=norm)
lc.set_array(y)
lc.set_linewidth(1) # The thickness of the line
ax.add_collection(lc)
ax.autoscale_view()
fig.colorbar(lc) #Add colorbar
plt.xlabel ("Hole depth")
plt.ylabel ("Vibration level")
plt.show()
UnhandledPromiseRejectionWarning: Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
[0] at ServerResponse.setHeader (_http_outgoing.js:526:11)
[0] at ServerResponse.header (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:771:10)
[0] at ServerResponse.send (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:170:12)
[0] at ServerResponse.json (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:267:15)
[0] at C:\Users\12345\Desktop\Capstone Project\src\controllers\/subjectController.js:35:43
[0] at processTicksAndRejections (internal/process/task_queues.js:97:5)
[0] (node:7684) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 11)
[0] (node:7684) UnhandledPromiseRejectionWarning: Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
[0] at ServerResponse.setHeader (_http_outgoing.js:526:11)
[0] at ServerResponse.header (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:771:10)
[0] at ServerResponse.send (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:170:12)
[0] at ServerResponse.json (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:267:15)
[0] at C:\Users\12345\Desktop\Capstone Project\src\controllers\/subjectController.js:35:43
[0] at processTicksAndRejections (internal/process/task_queues.js:97:5)
[0] (node:7684) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 12)
[0] (node:7684) UnhandledPromiseRejectionWarning: Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
[0] at ServerResponse.setHeader (_http_outgoing.js:526:11)
[0] at ServerResponse.header (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:771:10)
[0] at ServerResponse.send (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:170:12)
[0] at ServerResponse.json (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:267:15)
[0] at C:\Users\12345\Desktop\Capstone Project\src\controllers\/subjectController.js:35:43
[0] at processTicksAndRejections (internal/process/task_queues.js:97:5)
[0] (node:7684) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 13)
[0] (node:7684) UnhandledPromiseRejectionWarning: Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
[0] at ServerResponse.setHeader (_http_outgoing.js:526:11)
[0] at ServerResponse.header (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:771:10)
[0] at ServerResponse.send (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:170:12)
[0] at ServerResponse.json (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:267:15)
[0] at C:\Users\12345\Desktop\Capstone Project\src\controllers\/subjectController.js:35:43
[0] at processTicksAndRejections (internal/process/task_queues.js:97:5)
[0] (node:7684) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 14)
[0] (node:7684) UnhandledPromiseRejectionWarning: Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
[0] at ServerResponse.setHeader (_http_outgoing.js:526:11)
[0] at ServerResponse.header (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:771:10)
[0] at ServerResponse.send (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:170:12)
[0] at ServerResponse.json (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:267:15)
[0] at C:\Users\12345\Desktop\Capstone Project\src\controllers\/subjectController.js:35:43
[0] at processTicksAndRejections (internal/process/task_queues.js:97:5)
[0] (node:7684) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 15)
[0] (node:7684) UnhandledPromiseRejectionWarning: Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
[0] at ServerResponse.setHeader (_http_outgoing.js:526:11)
[0] at ServerResponse.header (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:771:10)
[0] at ServerResponse.send (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:170:12)
[0] at ServerResponse.json (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:267:15)
[0] at C:\Users\12345\Desktop\Capstone Project\src\controllers\/subjectController.js:35:43
[0] at processTicksAndRejections (internal/process/task_queues.js:97:5)
[0] (node:7684) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 16)
[0] (node:7684) UnhandledPromiseRejectionWarning: Error [ERR_HTTP_HEADERS_SENT]: Cannot set headers after they are sent to the client
[0] at ServerResponse.setHeader (_http_outgoing.js:526:11)
[0] at ServerResponse.header (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:771:10)
[0] at ServerResponse.send (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:170:12)
[0] at ServerResponse.json (C:\Users\12345\Desktop\Capstone Project\node_modules\express\lib\response.js:267:15)
[0] at C:\Users\12345\Desktop\Capstone Project\src\controllers\/subjectController.js:35:43
[0] at processTicksAndRejections (internal/process/task_queues.js:97:5)
[0] (node:7684) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled
[0] at C:\Users\12345\Desktop\Capstone Project\src\controllers\/subjectController.js:35:43
[0] at processTicksAndRejections (internal/process/task_queues.js:97:5)
[0] (node:7684) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 19)
答案 0 :(得分：0)
至少可以将问题详细说明一下，而不是复制并粘贴错误消息。
据我所知，express出现错误，因为您试图多次返回响应。这就是为什么要进行for循环并在每次迭代中发送响应的原因。
批处理更新的正确方法是为每个用户检查db并更新或创建，每个操作的结果应存储在数组中。遍历所有来自请求的用户后，然后在响应上返回结果数组。
在无需过多更改代码的情况下，它可能看起来像：
router.post('/', passport.authenticate('jwt', { session: false }), (req, res) => {
const result = []
for (var i = 0; i < req.body.subjects.length; i++) {
const subject = req.body.subjects[i];
const { errors, isValid } = validateSubjectInput(subject);
// Check validation
if (!isValid) {
result.push(errors);
} else {
const subjectFields = {};
for (let key in subject) {
if (subject[key]) subjectFields[key] = subject[key].trim();
}
subjectFields.id = subject.id ? subject.id.trim() : '';
console.log(subjectFields);
// See if there is already a subject with the subject ID
// with option {new: true} it will create an user if not exists
Subject.findOneAndUpdate(
{ _id: subject._id },
{ $set: subjectFields },
{ new: true }
).then(subject => result.push(subject));
}
}
res.json(result);
});