小编Tai*_*lam的帖子

尝试链接PyQt和Opencv视频源,无法理解如何应用while循环连续流式传输视频.它只需要一张照片.请任何人都可以帮助解决问题.

• PtQt = 5

• 蟒蛇= 3.6.1

class App(QWidget):
    def __init__(self):
        super().__init__()
        self.title = 'PyQt5 Video'
        self.left = 100
        self.top = 100
        self.width = 640
        self.height = 480
        self.initUI()


    def initUI(self):
        self.setWindowTitle(self.title)
        self.setGeometry(self.left, self.top, self.width, self.height)
        self.resize(1800, 1200)
        #create a label
        label = QLabel(self)
        cap = cv2.VideoCapture(0)
        ret, frame = cap.read()
        rgbImage = cv2.cvtColor(frame, cv2.COLOR_BGR2RGB)
        convertToQtFormat = QtGui.QImage(rgbImage.data, rgbImage.shape[1], rgbImage.shape[0],
                                         QtGui.QImage.Format_RGB888)
        convertToQtFormat = QtGui.QPixmap.fromImage(convertToQtFormat)
        pixmap = QPixmap(convertToQtFormat)
        resizeImage = pixmap.scaled(640, 480, QtCore.Qt.KeepAspectRatio)
        QApplication.processEvents()
        label.setPixmap(resizeImage)
        self.show()

if __name__ == '__main__':
    app = …

无法访问视频流.任何人都可以帮助我获取视频流.我在谷歌搜索了解决方案并在堆栈溢出中发布了另一个问题,但遗憾的是没有什么不能解决问题.

import cv2
cap = cv2.VideoCapture()
cap.open('http://192.168.4.133:80/videostream.cgi?user=admin&pwd=admin')
while(cap.isOpened()):
    ret, frame = cap.read()
    cv2.imshow('frame', frame)
    if cv2.waitKey(1) & 0xFF == ord('q'):
        break
cap.release()
cv2.destroyAllWindows()

import pyspark
from pyspark.sql import SparkSession
from pyspark.conf import SparkConf
import findspark
from pyspark.sql.functions import countDistinct
spark = SparkSession.builder \
.master("local[*]") \
.appName("usres mobile related information analysis") \
.config("spark.submit.deployMode", "client") \
.config("spark.executor.memory","3g") \
.config("spark.driver.maxResultSize", "1g") \
.config("spark.executor.pyspark.memory","3g") \
.enableHiveSupport() \
.getOrCreate()

handset_info = ora_tmp.select('some_value','some_value','some_value','some_value','some_value','some_value','some_value')

我用 3gb 执行内存和 3gb 执行 pyspark 内存配置 spark。我的数据库有超过 7000 万行。显示我调用

 handset_info.show()

方法是在 2-5 秒之间显示前 20 行。但是当我尝试运行以下代码时

mobile_info_df = handset_info.limit(30)
mobile_info_df.show()

显示前 30 行需要太多时间（3-4 小时）。花那么多时间是否合乎逻辑。我的配置有问题吗。我的笔记本电脑的配置是-

• 配备 8GB 内存的 Core i7（4 核）笔记本电脑

select COMMUNITY_AREA_NAME, count(COMMUNITY_AREA_NAME) as Number_Of_Schools
from CHICAGO_PUBLIC_SCHOOLS group by COMMUNITY_AREA_NAME order by 2 desc 

我编写了上面的sql查询来获取结果集,该结果集解释了拥有最多学校的社区名称,结果就是这样但是如何才能显示前10个列？我使用'限制10'.但它显示出一些错误.

select Top 10 COMMUNITY_AREA_NAME, count(COMMUNITY_AREA_NAME) as Number_Of_Schools
from CHICAGO_PUBLIC_SCHOOLS group by COMMUNITY_AREA_NAME order by 2 desc 
Limit 10;

错误:

Msg 102, Level 15, State 1, Line 3
Incorrect syntax near 'Limit'.