In jetso nano this work for me.
$ git clone https://github.com/JetsonHacksNano/buildOpenCV
$ cd buildOpenCV
If you are interested in it being realtime, then what you need is to add in a pre-processing filter to determine what gets scanned with the heavy-duty stuff. A good fast, very real time, pre-processing filter that will allow you to scan things that are more likely to be a coca-cola can than not before moving onto more iffy things is something like this: search the image for the biggest patches of color that are a certain tolerance away from the sqrt(pow(red,2) + pow(blue,2) + pow(green,2))
of your coca-cola can. Start with a very strict color tolerance, and work your way down to more lenient color tolerances. Then, when your robot runs out of an allotted time to process the current frame, it uses the currently found bottles for your purposes. Please note that you will have to tweak the RGB colors in the sqrt(pow(red,2) + pow(blue,2) + pow(green,2))
to get them just right.
Also, this is gona seem really dumb, but did you make sure to turn on -oFast
compiler optimizations when you compiled your C code?
Alternatively, with MTCNN and OpenCV(other dependencies including TensorFlow also required), you can:
1 Perform face detection(Input an image, output all boxes of detected faces):
from mtcnn.mtcnn import MTCNN
import cv2
face_detector = MTCNN()
img = cv2.imread("Anthony_Hopkins_0001.jpg")
detect_boxes = face_detector.detect_faces(img)
print(detect_boxes)
[{'box': [73, 69, 98, 123], 'confidence': 0.9996458292007446, 'keypoints': {'left_eye': (102, 116), 'right_eye': (150, 114), 'nose': (129, 142), 'mouth_left': (112, 168), 'mouth_right': (146, 167)}}]
2 save all detected faces to separate files:
for i in range(len(detect_boxes)):
box = detect_boxes[i]["box"]
face_img = img[box[1]:(box[1] + box[3]), box[0]:(box[0] + box[2])]
cv2.imwrite("face-{:03d}.jpg".format(i+1), face_img)
3 or Draw rectangles of all detected faces:
for box in detect_boxes:
box = box["box"]
pt1 = (box[0], box[1]) # top left
pt2 = (box[0] + box[2], box[1] + box[3]) # bottom right
cv2.rectangle(img, pt1, pt2, (0,255,0), 2)
cv2.imwrite("detected-boxes.jpg", img)
Alternatively, you could invert the image using the bitwise_not
function of OpenCV:
imagem = cv2.bitwise_not(imagem)
I liked this example.
For 2D matrix:
mat.rows – Number of rows in a 2D array.
mat.cols – Number of columns in a 2D array.
Or: C++: Size Mat::size() const
The method returns a matrix size: Size(cols, rows) . When the matrix is more than 2-dimensional, the returned size is (-1, -1).
For multidimensional matrix, you need to use
int thisSizes[3] = {2, 3, 4};
cv::Mat mat3D(3, thisSizes, CV_32FC1);
// mat3D.size tells the size of the matrix
// mat3D.size[0] = 2;
// mat3D.size[1] = 3;
// mat3D.size[2] = 4;
Note, here 2 for z axis, 3 for y axis, 4 for x axis. By x, y, z, it means the order of the dimensions. x index changes the fastest.
The patch is here: https://code.ros.org/trac/opencv/attachment/ticket/862/OpenCV-2.2-nov4l1.patch
By adding #ifdef HAVE_CAMV4L
around
#include <linux/videodev.h>
in OpenCV-2.2.0/modules/highgui/src/cap_v4l.cpp
and removing || defined (HAVE_CAMV4L2)
from line 174
allowed me to compile.
If for matching identical images ( same size/orientation )
// Compare two images by getting the L2 error (square-root of sum of squared error).
double getSimilarity( const Mat A, const Mat B ) {
if ( A.rows > 0 && A.rows == B.rows && A.cols > 0 && A.cols == B.cols ) {
// Calculate the L2 relative error between images.
double errorL2 = norm( A, B, CV_L2 );
// Convert to a reasonable scale, since L2 error is summed across all pixels of the image.
double similarity = errorL2 / (double)( A.rows * A.cols );
return similarity;
}
else {
//Images have a different size
return 100000000.0; // Return a bad value
}
May be helpful for late comers.
#include "stdafx.h"
#include "cv.h"
#include "highgui.h"
using namespace cv;
using namespace std;
int main(int argc, char *argv[])
{
if (argc != 2) {
cout << "Usage: display_Image ImageToLoadandDisplay" << endl;
return -1;
}else{
Mat image;
Mat grayImage;
image = imread(argv[1], IMREAD_COLOR);
if (!image.data) {
cout << "Could not open the image file" << endl;
return -1;
}
else {
int height = image.rows;
int width = image.cols;
cvtColor(image, grayImage, CV_BGR2GRAY);
namedWindow("Display window", WINDOW_AUTOSIZE);
imshow("Display window", image);
namedWindow("Gray Image", WINDOW_AUTOSIZE);
imshow("Gray Image", grayImage);
cvWaitKey(0);
image.release();
grayImage.release();
return 0;
}
}
}
Explicitly specifying the max_iter
resolves the warning as the default max_iter
is 100. [For Logistic Regression].
logreg = LogisticRegression(max_iter=1000)
Thanks nikie for that great Laplace suggestion. OpenCV docs pointed me in the same direction: using python, cv2 (opencv 2.4.10), and numpy...
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
numpy.max(cv2.convertScaleAbs(cv2.Laplacian(gray_image,3)))
result is between 0-255. I found anything over 200ish is very in focus, and by 100, it's noticeably blurry. the max never really gets much under 20 even if it's completely blurred.
If the path is correct and the name of the image is OK, but you are still getting the error
use:
from skimage import io
img = io.imread(file_path)
instead of:
cv2.imread(file_path)
The function imread loads an image from the specified file and returns it. If the image cannot be read (because of missing file, improper permissions, unsupported or invalid format), the function returns an empty matrix ( Mat::data==NULL ).
Here, you could use cv2.bitwise_and
function if you already have the mask image.
For check the below code:
img = cv2.imread('lena.jpg')
mask = cv2.imread('mask.png',0)
res = cv2.bitwise_and(img,img,mask = mask)
The output will be as follows for a lena image, and for rectangular mask.
1. Installing OpenCV 2.4.3
First, get OpenCV 2.4.3 from sourceforge.net. Its a self-extracting so just double click to start the installation. Install it in a directory, say C:\
.
Wait until all files get extracted. It will create a new directory C:\opencv
which
contains OpenCV header files, libraries, code samples, etc.
Now you need to add the directory C:\opencv\build\x86\vc10\bin
to your system PATH. This directory contains OpenCV DLLs required for running your code.
Open Control Panel → System → Advanced system settings → Advanced Tab → Environment variables...
On the System Variables section, select Path (1), Edit (2), and type C:\opencv\build\x86\vc10\bin;
(3), then click Ok.
On some computers, you may need to restart your computer for the system to recognize the environment path variables.
This will completes the OpenCV 2.4.3 installation on your computer.
2. Create a new project and set up Visual C++
Open Visual C++ and select File → New → Project... → Visual C++ → Empty Project. Give a name for your project (e.g: cvtest
) and set the project location (e.g: c:\projects
).
Click Ok. Visual C++ will create an empty project.
Make sure that "Debug" is selected in the solution configuration combobox. Right-click cvtest
and select Properties → VC++ Directories.
Select Include Directories to add a new entry and type C:\opencv\build\include
.
Click Ok to close the dialog.
Back to the Property dialog, select Library Directories to add a new entry and type C:\opencv\build\x86\vc10\lib
.
Click Ok to close the dialog.
Back to the property dialog, select Linker → Input → Additional Dependencies to add new entries. On the popup dialog, type the files below:
opencv_calib3d243d.lib
opencv_contrib243d.lib
opencv_core243d.lib
opencv_features2d243d.lib
opencv_flann243d.lib
opencv_gpu243d.lib
opencv_haartraining_engined.lib
opencv_highgui243d.lib
opencv_imgproc243d.lib
opencv_legacy243d.lib
opencv_ml243d.lib
opencv_nonfree243d.lib
opencv_objdetect243d.lib
opencv_photo243d.lib
opencv_stitching243d.lib
opencv_ts243d.lib
opencv_video243d.lib
opencv_videostab243d.lib
Note that the filenames end with "d" (for "debug"). Also note that if you have installed another version of OpenCV (say 2.4.9) these filenames will end with 249d instead of 243d (opencv_core249d.lib..etc).
Click Ok to close the dialog. Click Ok on the project properties dialog to save all settings.
NOTE:
These steps will configure Visual C++ for the "Debug" solution. For "Release" solution (optional), you need to repeat adding the OpenCV directories and in Additional Dependencies section, use:
opencv_core243.lib
opencv_imgproc243.lib
...
instead of:
opencv_core243d.lib
opencv_imgproc243d.lib
...
You've done setting up Visual C++, now is the time to write the real code. Right click your project and select Add → New Item... → Visual C++ → C++ File.
Name your file (e.g: loadimg.cpp
) and click Ok. Type the code below in the editor:
#include <opencv2/highgui/highgui.hpp>
#include <iostream>
using namespace cv;
using namespace std;
int main()
{
Mat im = imread("c:/full/path/to/lena.jpg");
if (im.empty())
{
cout << "Cannot load image!" << endl;
return -1;
}
imshow("Image", im);
waitKey(0);
}
The code above will load c:\full\path\to\lena.jpg
and display the image. You can
use any image you like, just make sure the path to the image is correct.
Type F5 to compile the code, and it will display the image in a nice window.
And that is your first OpenCV program!
3. Where to go from here?
Now that your OpenCV environment is ready, what's next?
c:\opencv\samples\cpp
.If you have only these regular shapes, there is a simple procedure as follows :
approxPolyDP
function.Below is my example in Python:
import numpy as np
import cv2
img = cv2.imread('shapes.png')
gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
ret,thresh = cv2.threshold(gray,127,255,1)
contours,h = cv2.findContours(thresh,1,2)
for cnt in contours:
approx = cv2.approxPolyDP(cnt,0.01*cv2.arcLength(cnt,True),True)
print len(approx)
if len(approx)==5:
print "pentagon"
cv2.drawContours(img,[cnt],0,255,-1)
elif len(approx)==3:
print "triangle"
cv2.drawContours(img,[cnt],0,(0,255,0),-1)
elif len(approx)==4:
print "square"
cv2.drawContours(img,[cnt],0,(0,0,255),-1)
elif len(approx) == 9:
print "half-circle"
cv2.drawContours(img,[cnt],0,(255,255,0),-1)
elif len(approx) > 15:
print "circle"
cv2.drawContours(img,[cnt],0,(0,255,255),-1)
cv2.imshow('img',img)
cv2.waitKey(0)
cv2.destroyAllWindows()
Below is the output:
Remember, it works only for regular shapes.
Alternatively to find circles, you can use houghcircles
. You can find a tutorial here.
Regarding iOS, OpenCV devs are developing some iOS samples this summer, So visit their site : www.code.opencv.org and contact them.
You can find slides of their tutorial here : http://code.opencv.org/svn/gsoc2012/ios/trunk/doc/CVPR2012_OpenCV4IOS_Tutorial.pdf
The images c, d, e , and f in the following show colorspace conversion they also happen to be numpy arrays <type 'numpy.ndarray'>
:
import numpy, cv2
def show_pic(p):
''' use esc to see the results'''
print(type(p))
cv2.imshow('Color image', p)
while True:
k = cv2.waitKey(0) & 0xFF
if k == 27: break
return
cv2.destroyAllWindows()
b = numpy.zeros([200,200,3])
b[:,:,0] = numpy.ones([200,200])*255
b[:,:,1] = numpy.ones([200,200])*255
b[:,:,2] = numpy.ones([200,200])*0
cv2.imwrite('color_img.jpg', b)
c = cv2.imread('color_img.jpg', 1)
c = cv2.cvtColor(c, cv2.COLOR_BGR2RGB)
d = cv2.imread('color_img.jpg', 1)
d = cv2.cvtColor(c, cv2.COLOR_RGB2BGR)
e = cv2.imread('color_img.jpg', -1)
e = cv2.cvtColor(c, cv2.COLOR_BGR2RGB)
f = cv2.imread('color_img.jpg', -1)
f = cv2.cvtColor(c, cv2.COLOR_RGB2BGR)
pictures = [d, c, f, e]
for p in pictures:
show_pic(p)
# show the matrix
print(c)
print(c.shape)
See here for more info: http://docs.opencv.org/modules/imgproc/doc/miscellaneous_transformations.html#cvtcolor
OR you could:
img = numpy.zeros([200,200,3])
img[:,:,0] = numpy.ones([200,200])*255
img[:,:,1] = numpy.ones([200,200])*255
img[:,:,2] = numpy.ones([200,200])*0
r,g,b = cv2.split(img)
img_bgr = cv2.merge([b,g,r])
Because you have multiple versions of NumPy installed.
Try pip uninstall numpy
and pip list | grep numpy
several times, until you see no output from pip list | grep numpy
.
Then pip install numpy
will get you the newest version of NumPy.
PIL (Python Imaging Library) and Numpy work well together.
I use the following functions.
from PIL import Image
import numpy as np
def load_image( infilename ) :
img = Image.open( infilename )
img.load()
data = np.asarray( img, dtype="int32" )
return data
def save_image( npdata, outfilename ) :
img = Image.fromarray( np.asarray( np.clip(npdata,0,255), dtype="uint8"), "L" )
img.save( outfilename )
The 'Image.fromarray' is a little ugly because I clip incoming data to [0,255], convert to bytes, then create a grayscale image. I mostly work in gray.
An RGB image would be something like:
outimg = Image.fromarray( ycc_uint8, "RGB" )
outimg.save( "ycc.tif" )
For me, I had to have OpenCV (3.4.2), Py-OpenCV (3.4.2), LibOpenCV (3.4.2).
My Python was version 3.5.6 with Anaconda in Windows OS 10.
Install opencv-python
(which is an unofficial pre-built OpenCV package for Python) by issuing the following command:
pip install opencv-python
in OpenCV 3.0 you can use it easily as follow:
#combine 2 images same as to concatenate images with two different sizes
h1, w1 = img1.shape[:2]
h2, w2 = img2.shape[:2]
#create empty martrix (Mat)
res = np.zeros(shape=(max(h1, h2), w1 + w2, 3), dtype=np.uint8)
# assign BGR values to concatenate images
for i in range(res.shape[2]):
# assign img1 colors
res[:h1, :w1, i] = np.ones([img1.shape[0], img1.shape[1]]) * img1[:, :, i]
# assign img2 colors
res[:h2, w1:w1 + w2, i] = np.ones([img2.shape[0], img2.shape[1]]) * img2[:, :, i]
output_img = res.astype('uint8')
Looks like the image is too big and the window simply doesn't fit the screen.
Create window with the cv2.WINDOW_NORMAL
flag, it will make it scalable. Then you can resize it to fit your screen like this:
from __future__ import division
import cv2
img = cv2.imread('1.jpg')
screen_res = 1280, 720
scale_width = screen_res[0] / img.shape[1]
scale_height = screen_res[1] / img.shape[0]
scale = min(scale_width, scale_height)
window_width = int(img.shape[1] * scale)
window_height = int(img.shape[0] * scale)
cv2.namedWindow('dst_rt', cv2.WINDOW_NORMAL)
cv2.resizeWindow('dst_rt', window_width, window_height)
cv2.imshow('dst_rt', img)
cv2.waitKey(0)
cv2.destroyAllWindows()
According to the OpenCV documentation CV_WINDOW_KEEPRATIO
flag should do the same, yet it doesn't and it's value not even presented in the python module.
I had the same error. The first time I used the 32-bit version of python but my computer is 64-bit. I then reinstalled the 64-bit version and succeeded.
Does the screenshot contain only the icon? If so, the L2 distance of the two images might suffice. If the L2 distance doesn't work, the next step is to try something simple and well established, like: Lucas-Kanade. Which I'm sure is available in OpenCV.
Here is a simple programe to capture a image from using laptop default camera.I hope that this will be very easy method for all.
import cv2
# 1.creating a video object
video = cv2.VideoCapture(0)
# 2. Variable
a = 0
# 3. While loop
while True:
a = a + 1
# 4.Create a frame object
check, frame = video.read()
# Converting to grayscale
#gray = cv2.cvtColor(frame,cv2.COLOR_BGR2GRAY)
# 5.show the frame!
cv2.imshow("Capturing",frame)
# 6.for playing
key = cv2.waitKey(1)
if key == ord('q'):
break
# 7. image saving
showPic = cv2.imwrite("filename.jpg",frame)
print(showPic)
# 8. shutdown the camera
video.release()
cv2.destroyAllWindows
You can see my github code here
$ apt-file search opencv.pc $ ls /usr/local/lib/pkgconfig/ $ sudo cp /usr/local/lib/pkgconfig/opencv4.pc /usr/lib/x86_64-linux-gnu/pkgconfig/opencv.pc $ pkg-config --modversion opencv
If you are using windows os, you can download your desired opencv unofficial windows binary from here, and type
something like pip install opencv_python-2.4.13.2-cp27-cp27m-win_amd64.whl
in the directory of binary file.
I understand this question has been answered but perhaps this might be useful to someone...
If you wish to copy the data into a separate cv::Mat object you could use a function similar to this:
void ExtractROI(Mat& inImage, Mat& outImage, Rect roi){
/* Create the image */
outImage = Mat(roi.height, roi.width, inImage.type(), Scalar(0));
/* Populate the image */
for (int i = roi.y; i < (roi.y+roi.height); i++){
uchar* inP = inImage.ptr<uchar>(i);
uchar* outP = outImage.ptr<uchar>(i-roi.y);
for (int j = roi.x; j < (roi.x+roi.width); j++){
outP[j-roi.x] = inP[j];
}
}
}
It would be important to note that this would only function properly on single channel images.
You can choose filling zero data or create zero Mat.
Filling zero data with setTo():
img.setTo(Scalar::all(0));
Create zero data with zeros():
img = zeros(img.size(), img.type());
The img changes address of memory.
A simple way of "binarize" an image is to compare to a threshold: For example you can compare all elements in a matrix against a value with opencv in c++
cv::Mat img = cv::imread("image.jpg", CV_LOAD_IMAGE_GRAYSCALE);
cv::Mat bw = img > 128;
In this way, all pixels in the matrix greater than 128 now are white, and these less than 128 or equals will be black
Optionally, and for me gave good results is to apply blur
cv::blur( bw, bw, cv::Size(3,3) );
Later you can save it as said before with:
cv::imwrite("image_bw.jpg", bw);
I am having OpenCV version 3.4.3 on MacOS. I was getting the same error as above.
I changed my code from
frame = cv2.resize(frame, (0,0), fx=0.5, fy=0.5)
to
frame = cv2.resize(frame, None, fx=0.5, fy=0.5)
Now its working fine for me.
A simple 4on4 pasting function that works-
def paste(background,foreground,pos=(0,0)):
#get position and crop pasting area if needed
x = pos[0]
y = pos[1]
bgWidth = background.shape[0]
bgHeight = background.shape[1]
frWidth = foreground.shape[0]
frHeight = foreground.shape[1]
width = bgWidth-x
height = bgHeight-y
if frWidth<width:
width = frWidth
if frHeight<height:
height = frHeight
# normalize alpha channels from 0-255 to 0-1
alpha_background = background[x:x+width,y:y+height,3] / 255.0
alpha_foreground = foreground[:width,:height,3] / 255.0
# set adjusted colors
for color in range(0, 3):
fr = alpha_foreground * foreground[:width,:height,color]
bg = alpha_background * background[x:x+width,y:y+height,color] * (1 - alpha_foreground)
background[x:x+width,y:y+height,color] = fr+bg
# set adjusted alpha and denormalize back to 0-255
background[x:x+width,y:y+height,3] = (1 - (1 - alpha_foreground) * (1 - alpha_background)) * 255
return background
This is what worked for me...
import cv2
import numpy as np
#Created an image (really an ndarray) with three channels
new_image = np.ndarray((3, num_rows, num_cols), dtype=int)
#Did manipulations for my project where my array values went way over 255
#Eventually returned numbers to between 0 and 255
#Converted the datatype to np.uint8
new_image = new_image.astype(np.uint8)
#Separated the channels in my new image
new_image_red, new_image_green, new_image_blue = new_image
#Stacked the channels
new_rgb = np.dstack([new_image_red, new_image_green, new_image_blue])
#Displayed the image
cv2.imshow("WindowNameHere", new_rgbrgb)
cv2.waitKey(0)
The hint is, the output file is created even if you get this error. The automatic deconstruction of vector starts after your code executed. Elements in the vector are deconstructed as well. This is most probably where the error occurs. The way you access the vector is through vector::operator[]
with an index read from stream. Try vector::at()
instead of vector::operator[]
. This won't solve your problem, but will show which assignment to the vector causes error.
Alternatively, cv2.merge()
can be used to turn a single channel binary mask layer into a three channel color image by merging the same layer together as the blue, green, and red layers of the new image. We pass in a list of the three color channel layers - all the same in this case - and the function returns a single image with those color channels. This effectively transforms a grayscale image of shape (height, width, 1)
into (height, width, 3)
To address your problem
I did some thresholding on an image and want to label the contours in green, but they aren't showing up in green because my image is in black and white.
This is because you're trying to display three channels on a single channel image. To fix this, you can simply merge the three single channels
image = cv2.imread('image.png')
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
gray_three = cv2.merge([gray,gray,gray])
Example
We create a color image with dimensions (200,200,3)
image = (np.random.standard_normal([200,200,3]) * 255).astype(np.uint8)
Next we convert it to grayscale and create another image using cv2.merge()
with three gray channels
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
gray_three = cv2.merge([gray,gray,gray])
We now draw a filled contour onto the single channel grayscale image (left) with shape (200,200,1)
and the three channel grayscale image with shape (200,200,3)
(right). The left image showcases the problem you're experiencing since you're trying to display three channels on a single channel image. After merging the grayscale image into three channels, we can now apply color onto the image
contour = np.array([[10,10], [190, 10], [190, 80], [10, 80]])
cv2.fillPoly(gray, [contour], [36,255,12])
cv2.fillPoly(gray_three, [contour], [36,255,12])
Full code
import cv2
import numpy as np
# Create random color image
image = (np.random.standard_normal([200,200,3]) * 255).astype(np.uint8)
# Convert to grayscale (1 channel)
gray = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY)
# Merge channels to create color image (3 channels)
gray_three = cv2.merge([gray,gray,gray])
# Fill a contour on both the single channel and three channel image
contour = np.array([[10,10], [190, 10], [190, 80], [10, 80]])
cv2.fillPoly(gray, [contour], [36,255,12])
cv2.fillPoly(gray_three, [contour], [36,255,12])
cv2.imshow('image', image)
cv2.imshow('gray', gray)
cv2.imshow('gray_three', gray_three)
cv2.waitKey()
Before installing libgtk2.0-dev and pkg-config or libqt4-dev. Make sure that you have uninstalled opencv. You can confirm this by running import cv2 on your python shell. If it fails, then install the needed packages and re-run cmake .
You can use cv2.rectangle()
:
cv2.rectangle(img, pt1, pt2, color, thickness, lineType, shift)
Draws a simple, thick, or filled up-right rectangle.
The function rectangle draws a rectangle outline or a filled rectangle
whose two opposite corners are pt1 and pt2.
Parameters
img Image.
pt1 Vertex of the rectangle.
pt2 Vertex of the rectangle opposite to pt1 .
color Rectangle color or brightness (grayscale image).
thickness Thickness of lines that make up the rectangle. Negative values,
like CV_FILLED , mean that the function has to draw a filled rectangle.
lineType Type of the line. See the line description.
shift Number of fractional bits in the point coordinates.
I have a PIL Image object and I want to draw rectangle on this image, but PIL's ImageDraw.rectangle() method does not have the ability to specify line width. I need to convert Image object to opencv2's image format and draw rectangle and convert back to Image object. Here is how I do it:
# im is a PIL Image object
im_arr = np.asarray(im)
# convert rgb array to opencv's bgr format
im_arr_bgr = cv2.cvtColor(im_arr, cv2.COLOR_RGB2BGR)
# pts1 and pts2 are the upper left and bottom right coordinates of the rectangle
cv2.rectangle(im_arr_bgr, pts1, pts2,
color=(0, 255, 0), thickness=3)
im_arr = cv2.cvtColor(im_arr_bgr, cv2.COLOR_BGR2RGB)
# convert back to Image object
im = Image.fromarray(im_arr)
The cvWaitKey
simply provides something of a delay. For example:
char c = cvWaitKey(33);
if( c == 27 ) break;
Tis was apart of my code in which a video was loaded into openCV and the frames outputted. The 33
number in the code means that after 33ms
, a new frame would be shown. Hence, the was a dely or time interval of 33ms
between each frame being shown on the screen.
Hope this helps.
This is a warning for usual. You can either disable it by
#pragma warning(disable:4996)
or simply use fopen_s like Microsoft has intended.
But be sure to use the pragma before other headers.
I know this is a really old question but i think i have a solution In the newer versions of openCV fonts are repesented by a number like this
FONT_HERSHEY_SIMPLEX = 0,
FONT_HERSHEY_PLAIN = 1,
FONT_HERSHEY_DUPLEX = 2,
FONT_HERSHEY_COMPLEX = 3,
FONT_HERSHEY_TRIPLEX = 4,
FONT_HERSHEY_COMPLEX_SMALL = 5,
FONT_HERSHEY_SCRIPT_SIMPLEX = 6,
FONT_HERSHEY_SCRIPT_COMPLEX = 7,
FONT_ITALIC = 16
so all you have to do is replace the font name with the corresponding number
cv2.putText(image,"Hello World!!!", (x,y), 0, 2, 255)
again i know its an old question but it may help someone in the future
finally solved my problem.
I created a new project in XCode with the sources and changed the C++ Standard Library from the default libc++ to libstdc++ as in this and this.
You can also try this filter
sharpen_filter = np.array([[0, -1, 0], [-1, 5, -1], [0, -1, 0]])
sharped_img = cv2.filter2D(image, -1, sharpen_filter)
Here's my EmguCV (a C# port of OpenCV) solution:
public static Image<TColor, TDepth> Rotate90<TColor, TDepth>(this Image<TColor, TDepth> img)
where TColor : struct, IColor
where TDepth : new()
{
var rot = new Image<TColor, TDepth>(img.Height, img.Width);
CvInvoke.cvTranspose(img.Ptr, rot.Ptr);
rot._Flip(FLIP.HORIZONTAL);
return rot;
}
public static Image<TColor, TDepth> Rotate180<TColor, TDepth>(this Image<TColor, TDepth> img)
where TColor : struct, IColor
where TDepth : new()
{
var rot = img.CopyBlank();
rot = img.Flip(FLIP.VERTICAL);
rot._Flip(FLIP.HORIZONTAL);
return rot;
}
public static void _Rotate180<TColor, TDepth>(this Image<TColor, TDepth> img)
where TColor : struct, IColor
where TDepth : new()
{
img._Flip(FLIP.VERTICAL);
img._Flip(FLIP.HORIZONTAL);
}
public static Image<TColor, TDepth> Rotate270<TColor, TDepth>(this Image<TColor, TDepth> img)
where TColor : struct, IColor
where TDepth : new()
{
var rot = new Image<TColor, TDepth>(img.Height, img.Width);
CvInvoke.cvTranspose(img.Ptr, rot.Ptr);
rot._Flip(FLIP.VERTICAL);
return rot;
}
Shouldn't be too hard to translate it back into C++.
An update to show how to do it in the recent versions of OpenCV:
import cv2
cv2.namedWindow("preview")
vc = cv2.VideoCapture(0)
if vc.isOpened(): # try to get the first frame
rval, frame = vc.read()
else:
rval = False
while rval:
cv2.imshow("preview", frame)
rval, frame = vc.read()
key = cv2.waitKey(20)
if key == 27: # exit on ESC
break
cv2.destroyWindow("preview")
vc.release()
It works in OpenCV-2.4.2 for me.
Referring to the first thread / another possibility VS cant open or find pdb file of the process is when you have your executable running in the background. I was working with mpiexec and ran into this issue. Always check your task manager and kill any exec process that your gonna build in your project. Once I did that, it debugged or built fine.
Also, if you try to continue with the warning , the breakpoints would not be hit and it would not have the current executable
For me the problem was that I was using different versions of Python in the same Eclipse project. My setup was not consistent with the Project Properties and the Run Configuration Python versions.
In Project > Properties > PyDev, I had the Interpreter set to Python2.7.11.
In Run Configurations > Interpreter, I was using the Default Interpreter. Changing it to Python 2.7.11 fixed the problem.
Your line:
img = cv2.rectangle(img,(x,y),(x+w,y+h),(255,0,0),2)
will draw a rectangle in the image, but the return value will be None, so img changes to None and cannot be drawn.
Try
cv2.rectangle(img,(x,y),(x+w,y+h),(255,0,0),2)
You can use image.shape to get the dimensions of the image. It returns 3 values. First value is width of an image, second is height and last one is channel. You dont need last value here so you can use below code to get height and width of image:
width, height = src.shape[:2]<br>
print(width, height)
In these two lines:
mask = cv2.line(mask, (a,b),(c,d), color[i].tolist(), 2)
frame = cv2.circle(frame,(a, b),5,color[i].tolist(),-1)
try instead:
cv2.line(mask, (a,b),(c,d), color[i].tolist(), 2)
cv2.circle(frame,(a, b),5,color[i].tolist(),-1)
I had the same problem and the variables were being returned empty
you can use skimage.img_as_ubyte(yourdata)
it will make you numpy array ranges from 0->255
from skimage import img_as_ubyte
img = img_as_ubyte(data)
cv2.imshow("Window", img)
This is the shortest version I could find,saving/hiding an extra conversion:
pil_image = PIL.Image.open('image.jpg')
opencvImage = cv2.cvtColor(numpy.array(pil_image), cv2.COLOR_RGB2BGR)
If reading a file from a URL:
import cStringIO
import urllib
file = cStringIO.StringIO(urllib.urlopen(r'http://stackoverflow.com/a_nice_image.jpg').read())
pil_image = PIL.Image.open(file)
opencvImage = cv2.cvtColor(numpy.array(pil_image), cv2.COLOR_RGB2BGR)
The pixels array is stored in the "data" attribute of cv::Mat. Let's suppose that we have a Mat matrix where each pixel has 3 bytes (CV_8UC3).
For this example, let's draw a RED pixel at position 100x50.
Mat foo;
int x=100, y=50;
Solution 1:
Create a macro function that obtains the pixel from the array.
#define PIXEL(frame, W, x, y) (frame+(y)*3*(W)+(x)*3)
//...
unsigned char * p = PIXEL(foo.data, foo.rols, x, y);
p[0] = 0; // B
p[1] = 0; // G
p[2] = 255; // R
Solution 2:
Get's the pixel using the method ptr.
unsigned char * p = foo.ptr(y, x); // Y first, X after
p[0] = 0; // B
p[1] = 0; // G
p[2] = 255; // R
To avoid using integer values to identify the VideoCapture
properties, one can use, e.g., cv2.cv.CV_CAP_PROP_FPS
in OpenCV 2.4 and cv2.CAP_PROP_FPS
in OpenCV 3.0. (See also Stefan's comment below.)
Here a utility function that works for both OpenCV 2.4 and 3.0:
# returns OpenCV VideoCapture property id given, e.g., "FPS"
def capPropId(prop):
return getattr(cv2 if OPCV3 else cv2.cv,
("" if OPCV3 else "CV_") + "CAP_PROP_" + prop)
OPCV3
is set earlier in my utilities code like this:
from pkg_resources import parse_version
OPCV3 = parse_version(cv2.__version__) >= parse_version('3')
I was facing similar issue with openCV on the python:3.7-slim
docker box. Following did the trick for me :
apt-get install build-essential libglib2.0-0 libsm6 libxext6 libxrender-dev
Please see if this helps !
I would like to suggest a method using the LAB color channel. Wikipedia has enough information regarding what the LAB color channel is about.
I have done the following using OpenCV 3.0.0 and python:
import cv2
#-----Reading the image-----------------------------------------------------
img = cv2.imread('Dog.jpg', 1)
cv2.imshow("img",img)
#-----Converting image to LAB Color model-----------------------------------
lab= cv2.cvtColor(img, cv2.COLOR_BGR2LAB)
cv2.imshow("lab",lab)
#-----Splitting the LAB image to different channels-------------------------
l, a, b = cv2.split(lab)
cv2.imshow('l_channel', l)
cv2.imshow('a_channel', a)
cv2.imshow('b_channel', b)
#-----Applying CLAHE to L-channel-------------------------------------------
clahe = cv2.createCLAHE(clipLimit=3.0, tileGridSize=(8,8))
cl = clahe.apply(l)
cv2.imshow('CLAHE output', cl)
#-----Merge the CLAHE enhanced L-channel with the a and b channel-----------
limg = cv2.merge((cl,a,b))
cv2.imshow('limg', limg)
#-----Converting image from LAB Color model to RGB model--------------------
final = cv2.cvtColor(limg, cv2.COLOR_LAB2BGR)
cv2.imshow('final', final)
#_____END_____#
You can run the code as it is. To know what CLAHE (Contrast Limited Adaptive Histogram Equalization)is about, you can again check Wikipedia.
It is because there is a DLL that your program is missing or can't find.
In your case I believe you are missing the openCV dlls. You can find these under the "build" directory that comes with open CV. If you are using VS2010 and building to an x86 program you can locate your dlls here under "opencv\build\x86\vc10\bin". Simply copy all these files to your Debug and Release folders and it should resolve your issues.
Generally you can resolve this issue using the following procedure:
Remember that you will need to have these DLLs in the same directory as your .exe. If you copy the .exe from the Release folder to somewhere else then you will need those DLLs copied with the .exe as well. For portability I tend to try and have a test Virtual Machine with a clean install of Windows (no updates or programs installed), and I walk through the Dependencies using the Dependency Walker one by one until the program is running happily.
This is a common problem. Also see these questions:
Can't run a vc++, error code 0xc0150002
The application was unable to start (0xc0150002) with libcurl C++ Windows 7 VS 2010
0xc0150002 Error when trying to run VC++ libcurl
The application was unable to start correctly 0xc150002
The application was unable to start correctly (0*0150002) - OpenCv
Good Luck!
Is canny
your own function? Do you use Canny from OpenCV inside it? If yes check if you feed suitable argument for Canny
- first Canny
argument should meet following criteria:
<type 'numpy.ndarray'>
dtype('uint8')
shape
should be 2-tuple
of int
s (tuple
containing exactly 2 integers)You can check it by printing respectively
type(variable_name)
variable_name.dtype
variable_name.shape
Replace variable_name
with name of variable you feed as first argument to Canny
.
The low-level way would be to access the matrix data directly. In an RGB image (which I believe OpenCV typically stores as BGR), and assuming your cv::Mat variable is called frame
, you could get the blue value at location (x
, y
) (from the top left) this way:
frame.data[frame.channels()*(frame.cols*y + x)];
Likewise, to get B, G, and R:
uchar b = frame.data[frame.channels()*(frame.cols*y + x) + 0];
uchar g = frame.data[frame.channels()*(frame.cols*y + x) + 1];
uchar r = frame.data[frame.channels()*(frame.cols*y + x) + 2];
Note that this code assumes the stride is equal to the width of the image.
In opencv, cv.namedWindow() just creates a window object as you determine, but not resizing the original image. You can use cv2.resize(img, resolution) to solve the problem.
Here's what it displays, a 740 * 411 resolution image.
image = cv2.imread("740*411.jpg")
cv2.imshow("image", image)
cv2.waitKey(0)
cv2.destroyAllWindows()
Here, it displays a 100 * 200 resolution image after resizing. Remember the resolution parameter use column first then is row.
image = cv2.imread("740*411.jpg")
image = cv2.resize(image, (200, 100))
cv2.imshow("image", image)
cv2.waitKey(0)
cv2.destroyAllWindows()
If you want to change the range to [0, 1], make sure the output data type is float
.
image = cv2.imread("lenacolor512.tiff", cv2.IMREAD_COLOR) # uint8 image
norm_image = cv2.normalize(image, None, alpha=0, beta=1, norm_type=cv2.NORM_MINMAX, dtype=cv2.CV_32F)
Based on what @J. Calleja said, you have two choices
If you want to random access the element of Mat, just simply use
Mat.at<data_Type>(row_num, col_num) = value;
If you want to continuous access, OpenCV provides Mat iterator compatible with STL iterator
and it's more C++
style
MatIterator_<double> it, end;
for( it = I.begin<double>(), end = I.end<double>(); it != end; ++it)
{
//do something here
}
or
for(int row = 0; row < mat.rows; ++row) {
float* p = mat.ptr(row); //pointer p points to the first place of each row
for(int col = 0; col < mat.cols; ++col) {
*p++; // operation here
}
}
If you have any difficulty to understand how Method 2 works, I borrow the picture from a blog post in the article Dynamic Two-dimensioned Arrays in C, which is much more intuitive and comprehensible.
See the picture below.
As pointed out by @Nenad Bulatovic one has to be careful while adding libraries(19th step). one should not add any trailing spaces while adding each library line by line. otherwise mingw goes haywire.
You can use this simple code in loop by incrementing count
cv2.imwrite("C:\Sharat\Python\Images\frame%d.jpg" % count, image)
images will be saved in the folder by name line frame0.jpg, frame1.jpg frame2.jpg etc..
I used a gradient based method in the program below. Added the resulting images. Please note that I'm using a scaled down version of the image for processing.
c++ version
The MIT License (MIT)
Copyright (c) 2014 Dhanushka Dangampola
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
#include "stdafx.h"
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <iostream>
using namespace cv;
using namespace std;
#define INPUT_FILE "1.jpg"
#define OUTPUT_FOLDER_PATH string("")
int _tmain(int argc, _TCHAR* argv[])
{
Mat large = imread(INPUT_FILE);
Mat rgb;
// downsample and use it for processing
pyrDown(large, rgb);
Mat small;
cvtColor(rgb, small, CV_BGR2GRAY);
// morphological gradient
Mat grad;
Mat morphKernel = getStructuringElement(MORPH_ELLIPSE, Size(3, 3));
morphologyEx(small, grad, MORPH_GRADIENT, morphKernel);
// binarize
Mat bw;
threshold(grad, bw, 0.0, 255.0, THRESH_BINARY | THRESH_OTSU);
// connect horizontally oriented regions
Mat connected;
morphKernel = getStructuringElement(MORPH_RECT, Size(9, 1));
morphologyEx(bw, connected, MORPH_CLOSE, morphKernel);
// find contours
Mat mask = Mat::zeros(bw.size(), CV_8UC1);
vector<vector<Point>> contours;
vector<Vec4i> hierarchy;
findContours(connected, contours, hierarchy, CV_RETR_CCOMP, CV_CHAIN_APPROX_SIMPLE, Point(0, 0));
// filter contours
for(int idx = 0; idx >= 0; idx = hierarchy[idx][0])
{
Rect rect = boundingRect(contours[idx]);
Mat maskROI(mask, rect);
maskROI = Scalar(0, 0, 0);
// fill the contour
drawContours(mask, contours, idx, Scalar(255, 255, 255), CV_FILLED);
// ratio of non-zero pixels in the filled region
double r = (double)countNonZero(maskROI)/(rect.width*rect.height);
if (r > .45 /* assume at least 45% of the area is filled if it contains text */
&&
(rect.height > 8 && rect.width > 8) /* constraints on region size */
/* these two conditions alone are not very robust. better to use something
like the number of significant peaks in a horizontal projection as a third condition */
)
{
rectangle(rgb, rect, Scalar(0, 255, 0), 2);
}
}
imwrite(OUTPUT_FOLDER_PATH + string("rgb.jpg"), rgb);
return 0;
}
python version
The MIT License (MIT)
Copyright (c) 2017 Dhanushka Dangampola
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
import cv2
import numpy as np
large = cv2.imread('1.jpg')
rgb = cv2.pyrDown(large)
small = cv2.cvtColor(rgb, cv2.COLOR_BGR2GRAY)
kernel = cv2.getStructuringElement(cv2.MORPH_ELLIPSE, (3, 3))
grad = cv2.morphologyEx(small, cv2.MORPH_GRADIENT, kernel)
_, bw = cv2.threshold(grad, 0.0, 255.0, cv2.THRESH_BINARY | cv2.THRESH_OTSU)
kernel = cv2.getStructuringElement(cv2.MORPH_RECT, (9, 1))
connected = cv2.morphologyEx(bw, cv2.MORPH_CLOSE, kernel)
# using RETR_EXTERNAL instead of RETR_CCOMP
contours, hierarchy = cv2.findContours(connected.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)
#For opencv 3+ comment the previous line and uncomment the following line
#_, contours, hierarchy = cv2.findContours(connected.copy(), cv2.RETR_EXTERNAL, cv2.CHAIN_APPROX_NONE)
mask = np.zeros(bw.shape, dtype=np.uint8)
for idx in range(len(contours)):
x, y, w, h = cv2.boundingRect(contours[idx])
mask[y:y+h, x:x+w] = 0
cv2.drawContours(mask, contours, idx, (255, 255, 255), -1)
r = float(cv2.countNonZero(mask[y:y+h, x:x+w])) / (w * h)
if r > 0.45 and w > 8 and h > 8:
cv2.rectangle(rgb, (x, y), (x+w-1, y+h-1), (0, 255, 0), 2)
cv2.imshow('rects', rgb)
Pay attention, if you use cv.CV_THRESH_BINARY
means every pixel greater than threshold becomes the maxValue (in your case 255), otherwise the value is 0. Obviously if your threshold is 0 everything becomes white (maxValue = 255) and if the value is 255 everything becomes black (i.e. 0).
If you don't want to work out a threshold, you can use the Otsu's method. But this algorithm only works with 8bit images in the implementation of OpenCV. If your image is 8bit use the algorithm like this:
cv.Threshold(im_gray_mat, im_bw_mat, threshold, 255, cv.CV_THRESH_BINARY | cv.CV_THRESH_OTSU);
No matter the value of threshold if you have a 8bit image.
Anyone who's looking for most convenient and robust way of writing MP4 files with OpenCV or FFmpeg, can see my state-of-the-art VidGear Video-Processing Python library's WriteGear API that works with both OpenCV backend and FFmpeg backend and even supports GPU encoders. Here's an example to encode with H264 encoder in WriteGear with FFmpeg backend:
# import required libraries
from vidgear.gears import WriteGear
import cv2
# define suitable (Codec,CRF,preset) FFmpeg parameters for writer
output_params = {"-vcodec":"libx264", "-crf": 0, "-preset": "fast"}
# Open suitable video stream, such as webcam on first index(i.e. 0)
stream = cv2.VideoCapture(0)
# Define writer with defined parameters and suitable output filename for e.g. `Output.mp4`
writer = WriteGear(output_filename = 'Output.mp4', logging = True, **output_params)
# loop over
while True:
# read frames from stream
(grabbed, frame) = stream.read()
# check for frame if not grabbed
if not grabbed:
break
# {do something with the frame here}
# lets convert frame to gray for this example
gray = cv2.cvtColor(frame, cv2.COLOR_BGR2GRAY)
# write gray frame to writer
writer.write(gray)
# Show output window
cv2.imshow("Output Gray Frame", gray)
# check for 'q' key if pressed
key = cv2.waitKey(1) & 0xFF
if key == ord("q"):
break
# close output window
cv2.destroyAllWindows()
# safely close video stream
stream.release()
# safely close writer
writer.close()
You haven't put the shared library in a location where the loader can find it. look inside the /usr/local/opencv
and /usr/local/opencv2
folders and see if either of them contains any shared libraries (files beginning in lib
and usually ending in .so
). when you find them, create a file called /etc/ld.so.conf.d/opencv.conf
and write to it the paths to the folders where the libraries are stored, one per line.
for example, if the libraries were stored under /usr/local/opencv/libopencv_core.so.2.4
then I would write this to my opencv.conf
file:
/usr/local/opencv/
Then run
sudo ldconfig -v
If you can't find the libraries, try running
sudo updatedb && locate libopencv_core.so.2.4
in a shell. You don't need to run updatedb
if you've rebooted since compiling OpenCV.
References:
About shared libraries on Linux: http://www.eyrie.org/~eagle/notes/rpath.html
About adding the OpenCV shared libraries: http://opencv.willowgarage.com/wiki/InstallGuide_Linux
I also face the same issue "OpenCV NoneType object has no attribute shape" and i solve this by changing the image location. I also use the PyCharm IDE. Currently my image location and class file in the same folder.
You can access most IP cameras using the method below.
import cv2
# insert the HTTP(S)/RSTP feed from the camera
url = "http://username:password@your_ip:your_port/tmpfs/auto.jpg"
# open the feed
cap = cv2.VideoCapture(url)
while True:
# read next frame
ret, frame = cap.read()
# show frame to user
cv2.imshow('frame', frame)
# if user presses q quit program
if cv2.waitKey(1) & 0xFF == ord("q"):
break
# close the connection and close all windows
cap.release()
cv2.destroyAllWindows()
Below is the way to crop an image.
image_path: The path to the image to edit
coords: A tuple of x/y coordinates (x1, y1, x2, y2)[open the image in mspaint and check the "ruler" in view tab to see the coordinates]
saved_location: Path to save the cropped image
from PIL import Image
def crop(image_path, coords, saved_location:
image_obj = Image.open("Path of the image to be cropped")
cropped_image = image_obj.crop(coords)
cropped_image.save(saved_location)
cropped_image.show()
if __name__ == '__main__':
image = "image.jpg"
crop(image, (100, 210, 710,380 ), 'cropped.jpg')
According to the latest updates for OpenCV 3.0 and higher, you need to change the Property Identifiers as follows in the code by Mehran:
cv2.cv.CV_CAP_PROP_POS_FRAMES
to
cv2.CAP_PROP_POS_FRAMES
and same applies to cv2.CAP_PROP_POS_FRAME_COUNT
.
Hope it helps.
cv::Mat m;
m.create(10, 10, CV_32FC3);
float *array = (float *)malloc( 3*sizeof(float)*10*10 );
cv::MatConstIterator_<cv::Vec3f> it = m.begin<cv::Vec3f>();
for (unsigned i = 0; it != m.end<cv::Vec3f>(); it++ ) {
for ( unsigned j = 0; j < 3; j++ ) {
*(array + i ) = (*it)[j];
i++;
}
}
Now you have a float array. In case of 8 bit, simply change float
to uchar
, Vec3f
to Vec3b
and CV_32FC3
to CV_8UC3
.
(base) C:\WINDOWS\system32>conda install C:\Users\Todd\Downloads\opencv3-3.1.0-py35_0.tar.bz2
I ran this command from anaconda terminal after I downloaded the version from https://anaconda.org/menpo/opencv3/files
This is the only way I could get cv2 to work and I tried everything for two days.
The answer that works on Ubuntu18, python3, opencv 3.2.0 is similar to the one above. But with the change in line cv2.waitKey(0)
. that means the program waits until a button is pressed.
With this code I found the key value for the arrow buttons: arrow up (82), down (84), arrow left(81) and Enter(10) and etc..
import cv2
img = cv2.imread('sof.jpg') # load a dummy image
while(1):
cv2.imshow('img',img)
k = cv2.waitKey(0)
if k==27: # Esc key to stop
break
elif k==-1: # normally -1 returned,so don't print it
continue
else:
print k # else print its value
Followed @hugh-pearse 's and @leszek-hanusz 's answers, with a little tweak. I had installed opencv from ubuntu 12.10 repository (libopencv-)* and had the same problem. Couldn't solve it with export OpenCV_DIR=/usr/share/OpenCV/
(since my OpenCVConfig.cmake whas there). It was solved when I also changed some lines on the OpenCVConfig.cmake file:
# ======================================================
# Include directories to add to the user project:
# ======================================================
# Provide the include directories to the caller
#SET(OpenCV_INCLUDE_DIRS "${OpenCV_INSTALL_PATH}/include/opencv;${OpenCV_INSTALL_PATH}/include")
SET(OpenCV_INCLUDE_DIRS "/usr/include/opencv;/usr/include/opencv2")
INCLUDE_DIRECTORIES(${OpenCV_INCLUDE_DIRS})
# ======================================================
# Link directories to add to the user project:
# ======================================================
# Provide the libs directory anyway, it may be needed in some cases.
#SET(OpenCV_LIB_DIR "${OpenCV_INSTALL_PATH}/lib")
SET(OpenCV_LIB_DIR "/usr/lib")
LINK_DIRECTORIES(${OpenCV_LIB_DIR})
And that worked on my Ubuntu 12.10. Remember to add the target_link_libraries(yourprojectname ${OpenCV_LIBS})
in your CMakeLists.txt.
There is no structure in numpy that allows you to append more data later.
Instead, numpy puts all of your data into a contiguous chunk of numbers (basically; a C array), and any resize requires allocating a new chunk of memory to hold it. Numpy's speed comes from being able to keep all the data in a numpy array in the same chunk of memory; e.g. mathematical operations can be parallelized for speed and you get less cache misses.
So you will have two kinds of solutions:
images = []
for i in range(100):
new_image = # pull image from somewhere
images.append(new_image)
images = np.stack(images, axis=3)
Note that there is no need to expand the dimensions of the individual image arrays first, nor do you need to know how many images you expect ahead of time.
To install OpenCV in Anaconda, start up the Anaconda command prompt and install OpenCV with
conda install -c https://conda.anaconda.org/menpo opencv3
Test that it works in your Anaconda Spyder or IPython console with
import cv2
You can also check the installed version using:
cv2.__version__
As per OpenCV docs(1), below steps using OpenCV manager is the recommended way to use OpenCV for production runs. But, OpenCV manager(2) is an additional install from Google play store. So, if you prefer a self contained apk(not using OpenCV manager) or is currently in development/testing phase, I suggest answer at https://stackoverflow.com/a/27421494/1180117.
Recommended steps for using OpenCV in Android Studio with OpenCV manager.
File -> Import Module
, choose sdk/java
folder in the unzipped opencv archive. build.gradle
under imported OpenCV module to update 4 fields to match your project's build.gradle
a) compileSdkVersion b) buildToolsVersion c) minSdkVersion and 4) targetSdkVersion. Application -> Module Settings
, and select the Dependencies
tab. Click +
icon at bottom(or right), choose Module Dependency
and select the imported OpenCV module.As the final step, in your Activity class, add snippet below.
public class SampleJava extends Activity {
private BaseLoaderCallback mLoaderCallback = new BaseLoaderCallback(this) {
@Override
public void onManagerConnected(int status) {
switch(status) {
case LoaderCallbackInterface.SUCCESS:
Log.i(TAG,"OpenCV Manager Connected");
//from now onwards, you can use OpenCV API
Mat m = new Mat(5, 10, CvType.CV_8UC1, new Scalar(0));
break;
case LoaderCallbackInterface.INIT_FAILED:
Log.i(TAG,"Init Failed");
break;
case LoaderCallbackInterface.INSTALL_CANCELED:
Log.i(TAG,"Install Cancelled");
break;
case LoaderCallbackInterface.INCOMPATIBLE_MANAGER_VERSION:
Log.i(TAG,"Incompatible Version");
break;
case LoaderCallbackInterface.MARKET_ERROR:
Log.i(TAG,"Market Error");
break;
default:
Log.i(TAG,"OpenCV Manager Install");
super.onManagerConnected(status);
break;
}
}
};
@Override
protected void onResume() {
super.onResume();
//initialize OpenCV manager
OpenCVLoader.initAsync(OpenCVLoader.OPENCV_VERSION_2_4_9, this, mLoaderCallback);
}
}
Note: You could only make OpenCV calls after you receive success callback on onManagerConnected
method. During run, you will be prompted for installation of OpenCV manager from play store, if it is not already installed. During development, if you don't have access to play store or is on emualtor, use appropriate OpenCV manager apk present in apk
folder under downloaded OpenCV sdk archive .
Pros
Cons
Android Studio 3.4 + OpenCV 4.1
Download the latest OpenCV zip file from here (current newest version is 4.1.0) and unzip it in your workspace or in another folder.
Create new Android Studio project normally. Click File->New->Import Module
, navigate to /path_to_unzipped_files/OpenCV-android-sdk/sdk/java
, set Module name as opencv
, click Next
and uncheck all options in the screen.
Enable Project
file view mode (default mode is Android
). In the opencv/build.gradle
file change apply plugin: 'com.android.application'
to apply plugin: 'com.android.library'
and replace application ID "org.opencv"
with
minSdkVersion 21
targetSdkVersion 28
(according the values in app/build.gradle
). Sync project with Gradle files.
Add this string to the dependencies block in the app/build.gradle
file
dependencies {
...
implementation project(path: ':opencv')
...
}
Select again Android
file view mode. Right click on app
module and goto New->Folder->JNI Folder
. Select change folder location and set src/main/jniLibs/
.
Select again Project
file view mode and copy all folders from /path_to_unzipped_files/OpenCV-android-sdk/sdk/native/libs
to app/src/main/jniLibs
.
Again in Android
file view mode right click on app
module and choose Link C++ Project with Gradle
. Select Build System ndk-build
and path to OpenCV.mk
file /path_to_unzipped_files/OpenCV-android-sdk/sdk/native/jni/OpenCV.mk
.
path_to_unzipped_files
must not contain any spaces, or you will get error!
To check OpenCV initialization add Toast message in MainActivity onCreate()
method:
Toast.makeText(MainActivity.this, String.valueOf(OpenCVLoader.initDebug()), Toast.LENGTH_LONG).show();
If initialization is successful you will see true
in Toast message else you will see false
.
Python: Reads image blob.jpg and performs blob detection with different parameters.
#!/usr/bin/python
# Standard imports
import cv2
import numpy as np;
# Read image
im = cv2.imread("blob.jpg")
# Setup SimpleBlobDetector parameters.
params = cv2.SimpleBlobDetector_Params()
# Change thresholds
params.minThreshold = 10
params.maxThreshold = 200
# Filter by Area.
params.filterByArea = True
params.minArea = 1500
# Filter by Circularity
params.filterByCircularity = True
params.minCircularity = 0.1
# Filter by Convexity
params.filterByConvexity = True
params.minConvexity = 0.87
# Filter by Inertia
params.filterByInertia = True
params.minInertiaRatio = 0.01
# Create a detector with the parameters
detector = cv2.SimpleBlobDetector(params)
# Detect blobs.
keypoints = detector.detect(im)
# Draw detected blobs as red circles.
# cv2.DRAW_MATCHES_FLAGS_DRAW_RICH_KEYPOINTS ensures
# the size of the circle corresponds to the size of blob
im_with_keypoints = cv2.drawKeypoints(im, keypoints, np.array([]), (0,0,255), cv2.DRAW_MATCHES_FLAGS_DRAW_RICH_KEYPOINTS)
# Show blobs
cv2.imshow("Keypoints", im_with_keypoints)
cv2.waitKey(0)
C++: Reads image blob.jpg and performs blob detection with different parameters.
#include "opencv2/opencv.hpp"
using namespace cv;
using namespace std;
int main(int argc, char** argv)
{
// Read image
#if CV_MAJOR_VERSION < 3 // If you are using OpenCV 2
Mat im = imread("blob.jpg", CV_LOAD_IMAGE_GRAYSCALE);
#else
Mat im = imread("blob.jpg", IMREAD_GRAYSCALE);
#endif
// Setup SimpleBlobDetector parameters.
SimpleBlobDetector::Params params;
// Change thresholds
params.minThreshold = 10;
params.maxThreshold = 200;
// Filter by Area.
params.filterByArea = true;
params.minArea = 1500;
// Filter by Circularity
params.filterByCircularity = true;
params.minCircularity = 0.1;
// Filter by Convexity
params.filterByConvexity = true;
params.minConvexity = 0.87;
// Filter by Inertia
params.filterByInertia = true;
params.minInertiaRatio = 0.01;
// Storage for blobs
std::vector<KeyPoint> keypoints;
#if CV_MAJOR_VERSION < 3 // If you are using OpenCV 2
// Set up detector with params
SimpleBlobDetector detector(params);
// Detect blobs
detector.detect(im, keypoints);
#else
// Set up detector with params
Ptr<SimpleBlobDetector> detector = SimpleBlobDetector::create(params);
// Detect blobs
detector->detect(im, keypoints);
#endif
// Draw detected blobs as red circles.
// DrawMatchesFlags::DRAW_RICH_KEYPOINTS flag ensures
// the size of the circle corresponds to the size of blob
Mat im_with_keypoints;
drawKeypoints(im, keypoints, im_with_keypoints, Scalar(0, 0, 255), DrawMatchesFlags::DRAW_RICH_KEYPOINTS);
// Show blobs
imshow("keypoints", im_with_keypoints);
waitKey(0);
}
The answer has been copied from this tutorial I wrote at LearnOpenCV.com explaining various parameters of SimpleBlobDetector. You can find additional details about the parameters in the tutorial.
For me, this type of error:
mingw-w64-x86_64/lib/gcc/x86_64-w64-mingw32/8.2.0/../../../../x86_64-w64-mingw32/bin/ld: mingw-w64-x86_64/x86_64-w64-mingw32/lib/libTransform360.a(VideoFrameTransform.cpp.obj):VideoFrameTransform.cpp:(.text+0xc7c):
undefined reference to `cv::Mat::Mat(cv::Mat const&, cv::Rect_<int> const&)'
meant load order, I had to do -lTransform360 -lopencv_dnn345 -lopencv...
just like that, that order.
And putting them right next to each other helped too, don't put -lTransform360
all the way at the beginning...or you'll get, for some freaky reason:
undefined reference to `VideoFrameTransform_new'
undefined reference to `VideoFrameTransform_generateMapForPlane'
...
For those using anaconda Python:
conda update anaconda
OCR which stands for Optical Character Recognition is a computer vision technique used to identify the different types of handwritten digits that are used in common mathematics. To perform OCR in OpenCV we will use the KNN algorithm which detects the nearest k neighbors of a particular data point and then classifies that data point based on the class type detected for n neighbors.
Data Used
This data contains 5000 handwritten digits where there are 500 digits for every type of digit. Each digit is of 20×20 pixel dimensions. We will split the data such that 250 digits are for training and 250 digits are for testing for every class.
Below is the implementation.
import numpy as np import cv2 # Read the image image = cv2.imread( 'digits.png' ) # gray scale conversion gray_img = cv2.cvtColor(image, cv2.COLOR_BGR2GRAY) # We will divide the image # into 5000 small dimensions # of size 20x20 divisions = list (np.hsplit(i, 100 ) for i in np.vsplit(gray_img, 50 )) # Convert into Numpy array # of size (50,100,20,20) NP_array = np.array(divisions) # Preparing train_data # and test_data. # Size will be (2500,20x20) train_data = NP_array[:,: 50 ].reshape( - 1 , 400 ).astype(np.float32) # Size will be (2500,20x20) test_data = NP_array[:, 50 : 100 ].reshape( - 1 , 400 ).astype(np.float32) # Create 10 different labels # for each type of digit k = np.arange( 10 ) train_labels = np.repeat(k, 250 )[:,np.newaxis] test_labels = np.repeat(k, 250 )[:,np.newaxis] # Initiate kNN classifier knn = cv2.ml.KNearest_create() # perform training of data knn.train(train_data, cv2.ml.ROW_SAMPLE, train_labels) # obtain the output from the # classifier by specifying the # number of neighbors. ret, output ,neighbours, distance = knn.findNearest(test_data, k = 3 ) # Check the performance and # accuracy of the classifier. # Compare the output with test_labels # to find out how many are wrong. matched = output = = test_labels correct_OP = np.count_nonzero(matched) #Calculate the accuracy. accuracy = (correct_OP * 100.0 ) / (output.size) # Display accuracy. print (accuracy) |
Output
91.64
Well, I decided to workout myself on my question to solve the above problem. What I wanted is to implement a simple OCR using KNearest or SVM features in OpenCV. And below is what I did and how. (it is just for learning how to use KNearest for simple OCR purposes).
1) My first question was about letter_recognition.data
file that comes with OpenCV samples. I wanted to know what is inside that file.
It contains a letter, along with 16 features of that letter.
And this SOF
helped me to find it. These 16 features are explained in the paper Letter Recognition Using Holland-Style Adaptive Classifiers
.
(Although I didn't understand some of the features at the end)
2) Since I knew, without understanding all those features, it is difficult to do that method. I tried some other papers, but all were a little difficult for a beginner.
So I just decided to take all the pixel values as my features. (I was not worried about accuracy or performance, I just wanted it to work, at least with the least accuracy)
I took the below image for my training data:
(I know the amount of training data is less. But, since all letters are of the same font and size, I decided to try on this).
To prepare the data for training, I made a small code in OpenCV. It does the following things:
key press manually
. This time we press the digit key ourselves corresponding to the letter in the box..txt
files.At the end of the manual classification of digits, all the digits in the training data (train.png
) are labeled manually by ourselves, image will look like below:
Below is the code I used for the above purpose (of course, not so clean):
import sys
import numpy as np
import cv2
im = cv2.imread('pitrain.png')
im3 = im.copy()
gray = cv2.cvtColor(im,cv2.COLOR_BGR2GRAY)
blur = cv2.GaussianBlur(gray,(5,5),0)
thresh = cv2.adaptiveThreshold(blur,255,1,1,11,2)
################# Now finding Contours ###################
contours,hierarchy = cv2.findContours(thresh,cv2.RETR_LIST,cv2.CHAIN_APPROX_SIMPLE)
samples = np.empty((0,100))
responses = []
keys = [i for i in range(48,58)]
for cnt in contours:
if cv2.contourArea(cnt)>50:
[x,y,w,h] = cv2.boundingRect(cnt)
if h>28:
cv2.rectangle(im,(x,y),(x+w,y+h),(0,0,255),2)
roi = thresh[y:y+h,x:x+w]
roismall = cv2.resize(roi,(10,10))
cv2.imshow('norm',im)
key = cv2.waitKey(0)
if key == 27: # (escape to quit)
sys.exit()
elif key in keys:
responses.append(int(chr(key)))
sample = roismall.reshape((1,100))
samples = np.append(samples,sample,0)
responses = np.array(responses,np.float32)
responses = responses.reshape((responses.size,1))
print "training complete"
np.savetxt('generalsamples.data',samples)
np.savetxt('generalresponses.data',responses)
Now we enter in to training and testing part.
For the testing part, I used the below image, which has the same type of letters I used for the training phase.
For training we do as follows:
.txt
files we already saved earlierFor testing purposes, we do as follows:
I included last two steps (training and testing) in single code below:
import cv2
import numpy as np
####### training part ###############
samples = np.loadtxt('generalsamples.data',np.float32)
responses = np.loadtxt('generalresponses.data',np.float32)
responses = responses.reshape((responses.size,1))
model = cv2.KNearest()
model.train(samples,responses)
############################# testing part #########################
im = cv2.imread('pi.png')
out = np.zeros(im.shape,np.uint8)
gray = cv2.cvtColor(im,cv2.COLOR_BGR2GRAY)
thresh = cv2.adaptiveThreshold(gray,255,1,1,11,2)
contours,hierarchy = cv2.findContours(thresh,cv2.RETR_LIST,cv2.CHAIN_APPROX_SIMPLE)
for cnt in contours:
if cv2.contourArea(cnt)>50:
[x,y,w,h] = cv2.boundingRect(cnt)
if h>28:
cv2.rectangle(im,(x,y),(x+w,y+h),(0,255,0),2)
roi = thresh[y:y+h,x:x+w]
roismall = cv2.resize(roi,(10,10))
roismall = roismall.reshape((1,100))
roismall = np.float32(roismall)
retval, results, neigh_resp, dists = model.find_nearest(roismall, k = 1)
string = str(int((results[0][0])))
cv2.putText(out,string,(x,y+h),0,1,(0,255,0))
cv2.imshow('im',im)
cv2.imshow('out',out)
cv2.waitKey(0)
And it worked, below is the result I got:
Here it worked with 100% accuracy. I assume this is because all the digits are of the same kind and the same size.
But anyway, this is a good start to go for beginners (I hope so).
I think using the matrix.at<type>(x,y)
is not the best way to iterate trough a Mat object!
If I recall correctly matrix.at<type>(x,y)
will iterate from the beginning of the matrix each time you call it(I might be wrong though).
I would suggest using cv::MatIterator_
cv::Mat someMat(1, 4, CV_64F, &someData);;
cv::MatIterator_<double> _it = someMat.begin<double>();
for(;_it!=someMat.end<double>(); _it++){
std::cout << *_it << std::endl;
}
You say that the matrices are the same dimensions, and yet you are trying to perform matrix multiplication on them. Multiplication of matrices with the same dimension is only possible if they are square. In your case, you get an assertion error, because the dimensions are not square. You have to be careful when multiplying matrices, as there are two possible meanings of multiply.
Matrix multiplication is where two matrices are multiplied directly. This operation multiplies matrix A of size [a x b] with matrix B of size [b x c] to produce matrix C of size [a x c]. In OpenCV it is achieved using the simple *
operator:
C = A * B
Element-wise multiplication is where each pixel in the output matrix is formed by multiplying that pixel in matrix A by its corresponding entry in matrix B. The input matrices should be the same size, and the output will be the same size as well. This is achieved using the mul()
function:
output = A.mul(B);
If you are interested to detect simple IR light blob through haar cascade, it will be very odd to do. Because simple IR blob does not have enough features to be trained through opencv like other objects (face, eyes,nose etc). Because IR is just a simple light having only one feature of brightness in my point of view. But if you want to learn how to train a classifier following link will help you alot.
http://note.sonots.com/SciSoftware/haartraining.html
And if you just want to detect IR blob, then you have two more possibilities, one is you go for DIP algorithms to detect bright region and the other one which I recommend you is you can use an IR cam which just pass the IR blob and you can detect easily the IR blob by using opencv blob functiuons. If you think an IR cam is expansive, you can make simple webcam to an IR cam by removing IR blocker (if any) and add visible light blocker i.e negative film, floppy material or any other. You can check the following link to convert simple webcam to IR cam.
http://www.metacafe.com/watch/385098/transform_your_webcam_into_an_infrared_cam/
I just do it like this:
CvCapture *capture = cvCreateFileCapture("rtsp://camera-address");
Also make sure this dll is available at runtime else cvCreateFileCapture will return NULL
opencv_ffmpeg200d.dll
The camera needs to allow unauthenticated access too, usually set via its web interface. MJPEG format worked via rtsp but MPEG4 didn't.
hth
Si
Note: This is not a duplicate, because the OP is aware that the image from cv2.imread
is in BGR format (unlike the suggested duplicate question that assumed it was RGB hence the provided answers only address that issue)
To illustrate, I've opened up this same color JPEG image:
once using the conversion
img = cv2.imread(path)
img_gray = cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
and another by loading it in gray scale mode
img_gray_mode = cv2.imread(path, cv2.IMREAD_GRAYSCALE)
Like you've documented, the diff between the two images is not perfectly 0, I can see diff pixels in towards the left and the bottom
I've summed up the diff too to see
import numpy as np
np.sum(diff)
# I got 6143, on a 494 x 750 image
I tried all cv2.imread()
modes
Among all the IMREAD_
modes for cv2.imread()
, only IMREAD_COLOR
and IMREAD_ANYCOLOR
can be converted using COLOR_BGR2GRAY
, and both of them gave me the same diff against the image opened in IMREAD_GRAYSCALE
The difference doesn't seem that big. My guess is comes from the differences in the numeric calculations in the two methods (loading grayscale vs conversion to grayscale)
Naturally what you want to avoid is fine tuning your code on a particular version of the image just to find out it was suboptimal for images coming from a different source.
In brief, let's not mix the versions and types in the processing pipeline.
So I'd keep the image sources homogenous, e.g. if you have capturing the image from a video camera in BGR, then I'd use BGR as the source, and do the BGR to grayscale conversion cv2.cvtColor(img, cv2.COLOR_BGR2GRAY)
Vice versa if my ultimate source is grayscale then I'd open the files and the video capture in gray scale cv2.imread(path, cv2.IMREAD_GRAYSCALE)
If you want as simple as possible, install from the repository:
sudo apt-get install python-opencv libopencv-dev python-numpy python-dev
If you are using Java for OpenCV, then you can use the following code.
Mat img = src.clone(); //Clone from the original image
img.setTo(new Scalar(255,255,255)); //This sets the whole image to white, it is R,G,B value
For your information, the python equivalent is:
imageBuffer = cv.LoadImage( strSrc )
nW = new X size
nH = new Y size
smallerImage = cv.CreateImage( (nH, nW), imageBuffer.depth, imageBuffer.nChannels )
cv.Resize( imageBuffer, smallerImage , interpolation=cv.CV_INTER_CUBIC )
cv.SaveImage( strDst, smallerImage )
uninstall existing numpy and install opencv-python will resolve the issue
jveitchmichaelis at https://github.com/ContinuumIO/anaconda-issues/issues/223 provided a thorough answer. Here I copied his answer:
The documentation in OpenCV says (hidden away) that you can only write to avi using OpenCV3. Whether that's true or not I've not been able to determine, but I've been unable to write to anything else.
However, OpenCV is mainly a computer vision library, not a video stream, codec and write one. Therefore, the developers tried to keep this part as simple as possible. Due to this OpenCV for video containers supports only the avi extension, its first version.
From: http://docs.opencv.org/3.1.0/d7/d9e/tutorial_video_write.html
My setup: I built OpenCV 3 from source using MSVC 2015, including ffmpeg. I've also downloaded and installed XVID and openh264 from Cisco, which I added to my PATH. I'm running Anaconda Python 3. I also downloaded a recent build of ffmpeg and added the bin folder to my path, though that shouldn't make a difference as its baked into OpenCV.
I'm running in Win 10 64-bit.
This code seems to work fine on my computer. It will generate a video containing random static:
writer = cv2.VideoWriter("output.avi", cv2.VideoWriter_fourcc(*"MJPG"), 30,(640,480)) for frame in range(1000): writer.write(np.random.randint(0, 255, (480,640,3)).astype('uint8')) writer.release()
Some things I've learned through trial and error:
- Only use '.avi', it's just a container, the codec is the important thing.
Be careful with specifying frame sizes. In the constructor you need to pass the frame size as (column, row) e.g. 640x480. However the array you pass in, is indexed as (row, column). See in the above example how it's switched?
If your input image has a different size to the VideoWriter, it will fail (often silently)
- Only pass in 8 bit images, manually cast your arrays if you have to (.astype('uint8'))
- In fact, never mind, just always cast. Even if you load in images using cv2.imread, you need to cast to uint8...
- MJPG will fail if you don't pass in a 3 channel, 8-bit image. I get an assertion failure for this at least.
- XVID also requires a 3 channel image but fails silently if you don't do this.
- H264 seems to be fine with a single channel image
- If you need raw output, say from a machine vision camera, you can use 'DIB '. 'RAW ' or an empty codec sometimes works. Oddly if I use DIB, I get an ffmpeg error, but the video is saved fine. If I use RAW, there isn't an error, but Windows Video player won't open it. All are fine in VLC.
In the end I think the key point is that OpenCV is not designed to be a video capture library - it doesn't even support sound. VideoWriter is useful, but 99% of the time you're better off saving all your images into a folder and using ffmpeg to turn them into a useful video.
One thing that needs to be mentioned. You have to use the x86 version of Python 2.7. OpenCV doesn't support Python x64. I banged my head on this for a bit until I figured that out.
That said, follow the steps in Abid Rahman K's answer. And as Antimony said, you'll need to do a 'from cv2 import cv'
cv2
uses numpy
for manipulating images, so the proper and best way to get the size of an image is using numpy.shape
. Assuming you are working with BGR images, here is an example:
>>> import numpy as np
>>> import cv2
>>> img = cv2.imread('foo.jpg')
>>> height, width, channels = img.shape
>>> print height, width, channels
600 800 3
In case you were working with binary images, img
will have two dimensions, and therefore you must change the code to: height, width = img.shape
You did everything except copying the new pixel value back to the image.
This line takes a copy of the pixel into a local variable:
Vec3b color = image.at<Vec3b>(Point(x,y));
So, after changing color
as you require, just set it back like this:
image.at<Vec3b>(Point(x,y)) = color;
So, in full, something like this:
Mat image = img;
for(int y=0;y<img.rows;y++)
{
for(int x=0;x<img.cols;x++)
{
// get pixel
Vec3b & color = image.at<Vec3b>(y,x);
// ... do something to the color ....
color[0] = 13;
color[1] = 13;
color[2] = 13;
// set pixel
//image.at<Vec3b>(Point(x,y)) = color;
//if you copy value
}
}
This function extracts images from video with 1 fps, IN ADDITION it identifies the last frame and stops reading also:
import cv2
import numpy as np
def extract_image_one_fps(video_source_path):
vidcap = cv2.VideoCapture(video_source_path)
count = 0
success = True
while success:
vidcap.set(cv2.CAP_PROP_POS_MSEC,(count*1000))
success,image = vidcap.read()
## Stop when last frame is identified
image_last = cv2.imread("frame{}.png".format(count-1))
if np.array_equal(image,image_last):
break
cv2.imwrite("frame%d.png" % count, image) # save frame as PNG file
print '{}.sec reading a new frame: {} '.format(count,success)
count += 1
Problem 1 : Different applications use different scales for HSV. For example gimp uses H = 0-360, S = 0-100 and V = 0-100
. But OpenCV uses H: 0-179, S: 0-255, V: 0-255
. Here i got a hue value of 22 in gimp. So I took half of it, 11, and defined range for that. ie (5,50,50) - (15,255,255)
.
Problem 2: And also, OpenCV uses BGR format, not RGB. So change your code which converts RGB to HSV as follows:
cv.CvtColor(frame, frameHSV, cv.CV_BGR2HSV)
Now run it. I got an output as follows:
Hope that is what you wanted. There are some false detections, but they are small, so you can choose biggest contour which is your lid.
EDIT:
As Karl Philip told in his comment, it would be good to add new code. But there is change of only a single line. So, I would like to add the same code implemented in new cv2
module, so users can compare the easiness and flexibility of new cv2
module.
import cv2
import numpy as np
img = cv2.imread('sof.jpg')
ORANGE_MIN = np.array([5, 50, 50],np.uint8)
ORANGE_MAX = np.array([15, 255, 255],np.uint8)
hsv_img = cv2.cvtColor(img,cv2.COLOR_BGR2HSV)
frame_threshed = cv2.inRange(hsv_img, ORANGE_MIN, ORANGE_MAX)
cv2.imwrite('output2.jpg', frame_threshed)
It gives the same result as above. But code is much more simpler.
Just copy the .dll files to C:\windows\system32\
1) Direct Answer: Try this:
sudo updatedb
locate OpenCVConfig.cmake
For me, I get:
/home/pkarasev3/source/opencv/build/OpenCVConfig.cmake
To see the version, you can try:
cat /home/pkarasev3/source/opencv/build/OpenCVConfig.cmake
giving
....
SET(OpenCV_VERSION 2.3.1)
....
2) Better Answer:
"sudo make install" is your enemy, don't do that when you need to compile/update the library often and possibly debug step through it's internal functions. Notice how my config file is in a local build directory, not in /usr/something. You will avoid this confusion in the future, and can maintain several different versions even (debug and release, for example).
Edit: the reason this questions seems to arise often for OpenCV as opposed to other libraries is that it changes rather dramatically and fast between versions, and many of the operations are not so well-defined / well-constrained so you can't just rely on it to be a black-box like you do for something like libpng or libjpeg. Thus, better to not install it at all really, but just compile and link to the build folder.
A pure CSS
solution (#content { min-height: 100%; }
) will work in a lot of cases, but not in all of them - especially IE6 and IE7.
Unfortunately, you will need to resort to a JavaScript solution in order to get the desired behavior.
This can be done by calculating the desired height for your content <div>
and setting it as a CSS property in a function:
function resizeContent() {
var contentDiv = document.getElementById('content');
var headerDiv = document.getElementById('header');
// This may need to be done differently on IE than FF, but you get the idea.
var viewPortHeight = window.innerHeight - headerDiv.clientHeight;
contentDiv.style.height =
Math.max(viewportHeight, contentDiv.clientHeight) + 'px';
}
You can then set this function as a handler for onLoad
and onResize
events:
<body onload="resizeContent()" onresize="resizeContent()">
. . .
</body>
I have my scripts organized in different folders for each package I pull in from bower, plus my own script for my app. Since you are going to list the order of these scripts somewhere, why not just list them in your gulp file? For new developers on your project, it's nice that all your script end-points are listed here. You can do this with gulp-add-src:
gulpfile.js
var gulp = require('gulp'),
less = require('gulp-less'),
minifyCSS = require('gulp-minify-css'),
uglify = require('gulp-uglify'),
concat = require('gulp-concat'),
addsrc = require('gulp-add-src'),
sourcemaps = require('gulp-sourcemaps');
// CSS & Less
gulp.task('css', function(){
gulp.src('less/all.less')
.pipe(sourcemaps.init())
.pipe(less())
.pipe(minifyCSS())
.pipe(sourcemaps.write('source-maps'))
.pipe(gulp.dest('public/css'));
});
// JS
gulp.task('js', function() {
gulp.src('resources/assets/bower/jquery/dist/jquery.js')
.pipe(addsrc.append('resources/assets/bower/bootstrap/dist/js/bootstrap.js'))
.pipe(addsrc.append('resources/assets/bower/blahblah/dist/js/blah.js'))
.pipe(addsrc.append('resources/assets/js/my-script.js'))
.pipe(sourcemaps.init())
.pipe(concat('all.js'))
.pipe(uglify())
.pipe(sourcemaps.write('source-maps'))
.pipe(gulp.dest('public/js'));
});
gulp.task('default',['css','js']);
Note: jQuery and Bootstrap added for demonstration purposes of order. Probably better to use CDNs for those since they are so widely used and browsers could have them cached from other sites already.
For Simple Direct Media Layer 2 (SDL2), after installing it on Ubuntu 16.04 via:
sudo apt-get install libsdl2-dev
I used the header:
#include <SDL2/SDL.h>
and the compiler linker command:
-lSDL2main -lSDL2
Additionally, you may also want to install:
apt-get install libsdl2-image-dev
apt-get install libsdl2-mixer-dev
apt-get install libsdl2-ttf-dev
With these headers:
#include <SDL2/SDL_image.h>
#include <SDL2/SDL_ttf.h>
#include <SDL2/SDL_mixer.h>
and the compiler linker commands:
-lSDL2_image
-lSDL2_ttf
-lSDL2_mixer
You can call a reset function before appending. Something like this:
function resetNewReviewBoardForm() {
$("#Description").val('');
$("#PersonName").text('');
$("#members").empty(); //this one what worked in my case
$("#EmailNotification").val('False');
}
With examples? Here's a simple one:
public class TwoInjectionStyles {
private Foo foo;
// Constructor injection
public TwoInjectionStyles(Foo f) {
this.foo = f;
}
// Setting injection
public void setFoo(Foo f) { this.foo = f; }
}
Personally, I prefer constructor injection when I can.
In both cases, the bean factory instantiates the TwoInjectionStyles
and Foo
instances and gives the former its Foo
dependency.
True you can't have different sized slides. NOT true the size of you slide doesn't matter. It will size it to your resolution, but you can click on the magnifying icon(at least on PP 2013) and you can then scroll in all directions of your slide in original resolution.
You can also achieve similar results by using 'query' and @:
eg:
df = pd.DataFrame({'A': [1, 2, 3], 'B': ['a', 'b', 'f']})
df = pd.DataFrame({'A' : [5,6,3,4], 'B' : [1,2,3, 5]})
list_of_values = [3,6]
result= df.query("A in @list_of_values")
result
A B
1 6 2
2 3 3
If you need an instance of HashMap, the best way is:
fileParameters = new HashMap<String,String>();
Since Map is an interface, you need to pick some class that instantiates it if you want to create an empty instance. HashMap seems as good as any other - so just use that.
I wrote some Applescript which prompts for a password via a dialog box and then builds a custom bash command, like this:
echo <password> | sudo -S <command>
I'm not sure if this helps.
It'd be nice if sudo accepted a pre-encrypted password, so I could encrypt it within my script and not worry about echoing clear text passwords around. However this works for me and my situation.
It shouldn't be possible for this to happen if you're just including the scripts on the page.
The "copyArray" function should always be available when the JavaScript code starts executing no matter if it is declared before or after it -- unless you're loading the JavaScript files in dynamically with a dependency library. There are all sorts of problems with timing if that's the case.
If you are using MySQL or MariaDB, the easiest and performant way dump CSV for single table is -
SELECT customer_id, firstname, surname INTO OUTFILE '/exportdata/customers.txt'
FIELDS TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
LINES TERMINATED BY '\n'
FROM customers;
Now you can use other techniques to repeat this command for multiple tables. See more details here:
In Swift 4 and Swift 3, To convert String to URL:
URL(string: String)
or,
URL.init(string: "yourURLString")
And to convert URL to String:
URL.absoluteString
The one below converts the 'contents' of the url to string
String(contentsOf: URL)
EDIT: Sorry, I should have remembered that this machine is decidedly non-standard, having plugged in various non-standard libc
implementations for academic purposes ;-)
As itoa()
is indeed non-standard, as mentioned by several helpful commenters, it is best to use sprintf(target_string,"%d",source_int)
or (better yet, because it's safe from buffer overflows) snprintf(target_string, size_of_target_string_in_bytes, "%d", source_int)
. I know it's not quite as concise or cool as itoa()
, but at least you can Write Once, Run Everywhere (tm) ;-)
You are correct in stating that the default gcc libc
does not include itoa()
, like several other platforms, due to it not technically being a part of the standard. See here for a little more info. Note that you have to
#include <stdlib.h>
Of course you already know this, because you wanted to use itoa()
on Linux after presumably using it on another platform, but... the code (stolen from the link above) would look like:
Example
/* itoa example */
#include <stdio.h>
#include <stdlib.h>
int main ()
{
int i;
char buffer [33];
printf ("Enter a number: ");
scanf ("%d",&i);
itoa (i,buffer,10);
printf ("decimal: %s\n",buffer);
itoa (i,buffer,16);
printf ("hexadecimal: %s\n",buffer);
itoa (i,buffer,2);
printf ("binary: %s\n",buffer);
return 0;
}
Output:
Enter a number: 1750 decimal: 1750 hexadecimal: 6d6 binary: 11011010110
Hope this helps!
For anyone else out there wondering how to do this, I have the following solution for SQL Server 2008 R2 and later:
USE master
go
DENY VIEW ANY DATABASE TO [user]
go
This will address exactly the requirement outlined above..
maps.google.com has a navigation service which can provide you route information in KML format.
To get kml file we need to form url with start and destination locations:
public static String getUrl(double fromLat, double fromLon,
double toLat, double toLon) {// connect to map web service
StringBuffer urlString = new StringBuffer();
urlString.append("http://maps.google.com/maps?f=d&hl=en");
urlString.append("&saddr=");// from
urlString.append(Double.toString(fromLat));
urlString.append(",");
urlString.append(Double.toString(fromLon));
urlString.append("&daddr=");// to
urlString.append(Double.toString(toLat));
urlString.append(",");
urlString.append(Double.toString(toLon));
urlString.append("&ie=UTF8&0&om=0&output=kml");
return urlString.toString();
}
Next you will need to parse xml (implemented with SAXParser) and fill data structures:
public class Point {
String mName;
String mDescription;
String mIconUrl;
double mLatitude;
double mLongitude;
}
public class Road {
public String mName;
public String mDescription;
public int mColor;
public int mWidth;
public double[][] mRoute = new double[][] {};
public Point[] mPoints = new Point[] {};
}
Network connection is implemented in different ways on Android and Blackberry, so you will have to first form url:
public static String getUrl(double fromLat, double fromLon,
double toLat, double toLon)
then create connection with this url and get InputStream.
Then pass this InputStream and get parsed data structure:
public static Road getRoute(InputStream is)
Full source code RoadProvider.java
class MapPathScreen extends MainScreen {
MapControl map;
Road mRoad = new Road();
public MapPathScreen() {
double fromLat = 49.85, fromLon = 24.016667;
double toLat = 50.45, toLon = 30.523333;
String url = RoadProvider.getUrl(fromLat, fromLon, toLat, toLon);
InputStream is = getConnection(url);
mRoad = RoadProvider.getRoute(is);
map = new MapControl();
add(new LabelField(mRoad.mName));
add(new LabelField(mRoad.mDescription));
add(map);
}
protected void onUiEngineAttached(boolean attached) {
super.onUiEngineAttached(attached);
if (attached) {
map.drawPath(mRoad);
}
}
private InputStream getConnection(String url) {
HttpConnection urlConnection = null;
InputStream is = null;
try {
urlConnection = (HttpConnection) Connector.open(url);
urlConnection.setRequestMethod("GET");
is = urlConnection.openInputStream();
} catch (IOException e) {
e.printStackTrace();
}
return is;
}
}
See full code on J2MEMapRouteBlackBerryEx on Google Code
public class MapRouteActivity extends MapActivity {
LinearLayout linearLayout;
MapView mapView;
private Road mRoad;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mapView = (MapView) findViewById(R.id.mapview);
mapView.setBuiltInZoomControls(true);
new Thread() {
@Override
public void run() {
double fromLat = 49.85, fromLon = 24.016667;
double toLat = 50.45, toLon = 30.523333;
String url = RoadProvider
.getUrl(fromLat, fromLon, toLat, toLon);
InputStream is = getConnection(url);
mRoad = RoadProvider.getRoute(is);
mHandler.sendEmptyMessage(0);
}
}.start();
}
Handler mHandler = new Handler() {
public void handleMessage(android.os.Message msg) {
TextView textView = (TextView) findViewById(R.id.description);
textView.setText(mRoad.mName + " " + mRoad.mDescription);
MapOverlay mapOverlay = new MapOverlay(mRoad, mapView);
List<Overlay> listOfOverlays = mapView.getOverlays();
listOfOverlays.clear();
listOfOverlays.add(mapOverlay);
mapView.invalidate();
};
};
private InputStream getConnection(String url) {
InputStream is = null;
try {
URLConnection conn = new URL(url).openConnection();
is = conn.getInputStream();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return is;
}
@Override
protected boolean isRouteDisplayed() {
return false;
}
}
See full code on J2MEMapRouteAndroidEx on Google Code
It's probably not what you want, but a tool like re2c can compile POSIX(-ish) regular expressions to ANSI C. It's written as a replacement for lex
, but this approach allows you to sacrifice flexibility and legibility for the last bit of speed, if you really need it.
Assuming your example text is representative of all the text, one line would consume about 75 bytes on my machine:
In [3]: sys.getsizeof('usedfor zipper fasten_coat')
Out[3]: 75
Doing some rough math:
75 bytes * 8,000,000 lines / 1024 / 1024 = ~572 MB
So roughly 572 meg to store the strings alone for one of these files. Once you start adding in additional, similarly structured and sized files, you'll quickly approach your virtual address space limits, as mentioned in @ShadowRanger's answer.
If upgrading your python isn't feasible for you, or if it only kicks the can down the road (you have finite physical memory after all), you really have two options: write your results to temporary files in-between loading in and reading the input files, or write your results to a database. Since you need to further post-process the strings after aggregating them, writing to a database would be the superior approach.
// mutiple image retrieve
File folPath = new File(getIntent().getStringExtra("folder_path"));
File[] imagep = folPath.listFiles();
for (int i = 0; i < imagep.length ; i++) {
imageModelList.add(new ImageModel(imagep[i].getAbsolutePath(), Uri.parse(imagep[i].getAbsolutePath())));
}
imagesAdapter.notifyDataSetChanged();
I wrote two using statements inside a try/catch block and I could see the exception was being caught the same way if it's placed within the inner using statement just as ShaneLS example.
try
{
using (var con = new SqlConnection(@"Data Source=..."))
{
var cad = "INSERT INTO table VALUES (@r1,@r2,@r3)";
using (var insertCommand = new SqlCommand(cad, con))
{
insertCommand.Parameters.AddWithValue("@r1", atxt);
insertCommand.Parameters.AddWithValue("@r2", btxt);
insertCommand.Parameters.AddWithValue("@r3", ctxt);
con.Open();
insertCommand.ExecuteNonQuery();
}
}
}
catch (Exception ex)
{
MessageBox.Show("Error: " + ex.Message, "UsingTest", MessageBoxButtons.OK, MessageBoxIcon.Error);
}
No matter where's the try/catch placed, the exception will be caught without issues.
The answers from @unbeli and @Niklas are good, but @unbeli's answer does not work for all hex strings and it is desirable to do the decoding without importing an extra library (codecs). The following should work (but will not be very efficient for large strings):
>>> result = bytes.fromhex((lambda s: ("%s%s00" * (len(s)//2)) % tuple(s))('4a82fdfeff00')).decode('utf-16-le')
>>> result == '\x4a\x82\xfd\xfe\xff\x00'
True
Basically, it works around having invalid utf-8 bytes by padding with zeros and decoding as utf-16.
Kotlin 2020: Very simple method
After dialog.show()
use:
dialog.getButton(AlertDialog.BUTTON_NEGATIVE).setTextColor(ContextCompat.getColor(requireContext(), R.color.yourColor))
In Spring Boot 2, the easiest way is to declare in your application.properties:
spring.jackson.serialization.WRITE_ENUMS_USING_TO_STRING=true
spring.jackson.deserialization.READ_ENUMS_USING_TO_STRING=true
and define the toString() method of your enums.
Following is a list of solutions to centering things in CSS horizontally. The snippet includes all of them.
html {_x000D_
font: 1.25em/1.5 Georgia, Times, serif;_x000D_
}_x000D_
_x000D_
pre {_x000D_
color: #fff;_x000D_
background-color: #333;_x000D_
padding: 10px;_x000D_
}_x000D_
_x000D_
blockquote {_x000D_
max-width: 400px;_x000D_
background-color: #e0f0d1;_x000D_
}_x000D_
_x000D_
blockquote > p {_x000D_
font-style: italic;_x000D_
}_x000D_
_x000D_
blockquote > p:first-of-type::before {_x000D_
content: open-quote;_x000D_
}_x000D_
_x000D_
blockquote > p:last-of-type::after {_x000D_
content: close-quote;_x000D_
}_x000D_
_x000D_
blockquote > footer::before {_x000D_
content: "\2014";_x000D_
}_x000D_
_x000D_
.container,_x000D_
blockquote {_x000D_
position: relative;_x000D_
padding: 20px;_x000D_
}_x000D_
_x000D_
.container {_x000D_
background-color: tomato;_x000D_
}_x000D_
_x000D_
.container::after,_x000D_
blockquote::after {_x000D_
position: absolute;_x000D_
right: 0;_x000D_
bottom: 0;_x000D_
padding: 2px 10px;_x000D_
border: 1px dotted #000;_x000D_
background-color: #fff;_x000D_
}_x000D_
_x000D_
.container::after {_x000D_
content: ".container-" attr(data-num);_x000D_
z-index: 1;_x000D_
}_x000D_
_x000D_
blockquote::after {_x000D_
content: ".quote-" attr(data-num);_x000D_
z-index: 2;_x000D_
}_x000D_
_x000D_
.container-4 {_x000D_
margin-bottom: 200px;_x000D_
}_x000D_
_x000D_
/**_x000D_
* Solution 1_x000D_
*/_x000D_
.quote-1 {_x000D_
max-width: 400px;_x000D_
margin-right: auto;_x000D_
margin-left: auto;_x000D_
}_x000D_
_x000D_
/**_x000D_
* Solution 2_x000D_
*/_x000D_
.container-2 {_x000D_
text-align: center;_x000D_
}_x000D_
_x000D_
.quote-2 {_x000D_
display: inline-block;_x000D_
text-align: left;_x000D_
}_x000D_
_x000D_
/**_x000D_
* Solution 3_x000D_
*/_x000D_
.quote-3 {_x000D_
display: table;_x000D_
margin-right: auto;_x000D_
margin-left: auto;_x000D_
}_x000D_
_x000D_
/**_x000D_
* Solution 4_x000D_
*/_x000D_
.container-4 {_x000D_
position: relative;_x000D_
}_x000D_
_x000D_
.quote-4 {_x000D_
position: absolute;_x000D_
left: 50%;_x000D_
transform: translateX(-50%);_x000D_
}_x000D_
_x000D_
/**_x000D_
* Solution 5_x000D_
*/_x000D_
.container-5 {_x000D_
display: flex;_x000D_
justify-content: center;_x000D_
}
_x000D_
<main>_x000D_
<h1>CSS: Horizontal Centering</h1>_x000D_
_x000D_
<h2>Uncentered Example</h2>_x000D_
<p>This is the scenario: We have a container with an element inside of it that we want to center. I just added a little padding and background colors so both elements are distinquishable.</p>_x000D_
_x000D_
<div class="container container-0" data-num="0">_x000D_
<blockquote class="quote-0" data-num="0">_x000D_
<p>My friend Data. You see things with the wonder of a child. And that makes you more human than any of us.</p>_x000D_
<footer>Tasha Yar about Data</footer>_x000D_
</blockquote>_x000D_
</div>_x000D_
_x000D_
<h2>Solution 1: Using <code>max-width</code> & <code>margin</code> (IE7)</h2>_x000D_
_x000D_
<p>This method is widely used. The upside here is that only the element which one wants to center needs rules.</p>_x000D_
_x000D_
<pre><code>.quote-1 {_x000D_
max-width: 400px;_x000D_
margin-right: auto;_x000D_
margin-left: auto;_x000D_
}</code></pre>_x000D_
_x000D_
<div class="container container-1" data-num="1">_x000D_
<blockquote class="quote quote-1" data-num="1">_x000D_
<p>My friend Data. You see things with the wonder of a child. And that makes you more human than any of us.</p>_x000D_
<footer>Tasha Yar about Data</footer>_x000D_
</blockquote>_x000D_
</div>_x000D_
_x000D_
<h2>Solution 2: Using <code>display: inline-block</code> and <code>text-align</code> (IE8)</h2>_x000D_
_x000D_
<p>This method utilizes that <code>inline-block</code> elements are treated as text and as such they are affected by the <code>text-align</code> property. This does not rely on a fixed width which is an upside. This is helpful for when you don’t know the number of elements in a container for example.</p>_x000D_
_x000D_
<pre><code>.container-2 {_x000D_
text-align: center;_x000D_
}_x000D_
_x000D_
.quote-2 {_x000D_
display: inline-block;_x000D_
text-align: left;_x000D_
}</code></pre>_x000D_
_x000D_
<div class="container container-2" data-num="2">_x000D_
<blockquote class="quote quote-2" data-num="2">_x000D_
<p>My friend Data. You see things with the wonder of a child. And that makes you more human than any of us.</p>_x000D_
<footer>Tasha Yar about Data</footer>_x000D_
</blockquote>_x000D_
</div>_x000D_
_x000D_
<h2>Solution 3: Using <code>display: table</code> and <code>margin</code> (IE8)</h2>_x000D_
_x000D_
<p>Very similar to the second solution but only requires to apply rules on the element that is to be centered.</p>_x000D_
_x000D_
<pre><code>.quote-3 {_x000D_
display: table;_x000D_
margin-right: auto;_x000D_
margin-left: auto;_x000D_
}</code></pre>_x000D_
_x000D_
<div class="container container-3" data-num="3">_x000D_
<blockquote class="quote quote-3" data-num="3">_x000D_
<p>My friend Data. You see things with the wonder of a child. And that makes you more human than any of us.</p>_x000D_
<footer>Tasha Yar about Data</footer>_x000D_
</blockquote>_x000D_
</div>_x000D_
_x000D_
<h2>Solution 4: Using <code>translate()</code> and <code>position</code> (IE9)</h2>_x000D_
_x000D_
<p>Don’t use as a general approach for horizontal centering elements. The downside here is that the centered element will be removed from the document flow. Notice the container shrinking to zero height with only the padding keeping it visible. This is what <i>removing an element from the document flow</i> means.</p>_x000D_
_x000D_
<p>There are however applications for this technique. For example, it works for <b>vertically</b> centering by using <code>top</code> or <code>bottom</code> together with <code>translateY()</code>.</p>_x000D_
_x000D_
<pre><code>.container-4 {_x000D_
position: relative;_x000D_
}_x000D_
_x000D_
.quote-4 {_x000D_
position: absolute;_x000D_
left: 50%;_x000D_
transform: translateX(-50%);_x000D_
}</code></pre>_x000D_
_x000D_
<div class="container container-4" data-num="4">_x000D_
<blockquote class="quote quote-4" data-num="4">_x000D_
<p>My friend Data. You see things with the wonder of a child. And that makes you more human than any of us.</p>_x000D_
<footer>Tasha Yar about Data</footer>_x000D_
</blockquote>_x000D_
</div>_x000D_
_x000D_
<h2>Solution 5: Using Flexible Box Layout Module (IE10+ with vendor prefix)</h2>_x000D_
_x000D_
<p></p>_x000D_
_x000D_
<pre><code>.container-5 {_x000D_
display: flex;_x000D_
justify-content: center;_x000D_
}</code></pre>_x000D_
_x000D_
<div class="container container-5" data-num="5">_x000D_
<blockquote class="quote quote-5" data-num="5">_x000D_
<p>My friend Data. You see things with the wonder of a child. And that makes you more human than any of us.</p>_x000D_
<footer>Tasha Yar about Data</footer>_x000D_
</blockquote>_x000D_
</div>_x000D_
</main>
_x000D_
display: flex
.container {
display: flex;
justify-content: center;
}
Notes:
max-width
& margin
You can horizontally center a block-level element by assigning a fixed width and setting margin-right
and margin-left
to auto
.
.container ul {
/* for IE below version 7 use `width` instead of `max-width` */
max-width: 800px;
margin-right: auto;
margin-left: auto;
}
Notes:
transform: translatex(-50%)
& left: 50%
This is similar to the quirky centering method which uses absolute positioning and negative margins.
.container {
position: relative;
}
.container ul {
position: absolute;
left: 50%;
transform: translatex(-50%);
}
Notes:
top
instead of left
and translateY()
instead of translateX()
. The two can even be combined. transform2d
display: table
& margin
Just like the first solution, you use auto values for right and left margins, but don’t assign a width. If you don’t need to support IE7 and below, this is better suited, although it feels kind of hacky to use the table
property value for display
.
.container ul {
display: table;
margin-right: auto;
margin-left: auto;
}
display: inline-block
& text-align
Centering an element just like you would do with regular text is possible as well. Downside: You need to assign values to both a container and the element itself.
.container {
text-align: center;
}
.container ul {
display: inline-block;
/* One most likely needs to realign flow content */
text-align: initial;
}
Notes:
I had this same problem and it occurred because I had hit the enter key when adding code in a text string.
Because it was a long string of text I wanted to see it all without having to scroll in my text editor, however hitting enter added an invisible character to the string which was illegal. I was using Sublime Text as my editor.
I am storing a class object into a string using toString() method. Now, I want to convert the string into that class object.
Your question is ambiguous. It could mean at least two different things, one of which is ... well ... a serious misconception on your part.
If you did this:
SomeClass object = ...
String s = object.toString();
then the answer is that there is no simple way to turn s
back into an instance of SomeClass
. You couldn't do it even if the toString()
method gave you one of those funky "SomeClass@xxxxxxxx" strings. (That string does not encode the state of the object, or even a reference to the object. The xxxxxxxx part is the object's identity hashcode. It is not unique, and cannot be magically turned back into a reference to the object.)
The only way you could turn the output of toString
back into an object would be to:
SomeClass.toString()
method so that included all relevant state for the object in the String it produced, andtoString()
method.This is probably a bad approach. Certainly, it is a lot of work to do this for non-trivial classes.
If you did something like this:
SomeClass object = ...
Class c = object.getClass();
String cn = c.toString();
then you could get the same Class
object back (i.e. the one that is in c
) as follows:
Class c2 = Class.forName(cn);
This gives you the Class
but there is no magic way to reconstruct the original instance using it. (Obviously, the name of the class does not contain the state of the object.)
If you are looking for a way to serialize / deserialize an arbitrary object without going to the effort of coding the unparse / parse methods yourself, then you shouldn't be using toString()
method at all. Here are some alternatives that you can use:
Each of these approaches has advantages and disadvantages ... which I won't go into here.
now Application-Level Rate Limiting 200 calls per hour !
Hope this could help someone
$(document).on("input", ".numeric", function() {
this.value = this.value.match(/^\d+\.?\d{0,2}/);});
It is a way of generating a valid URL, generally using data already obtained. For instance, using the title of an article to generate a URL.
Below worked for me:
When you come to Server Configuration Screen, Change the Account Name of Database Engine Service to NT AUTHORITY\NETWORK SERVICE and continue installation and it will successfully install all components without any error. - See more at: https://superpctricks.com/sql-install-error-database-engine-recovery-handle-failed/
Try this
function submitRequest(buttonId) {
if (document.getElementById(buttonId) == null
|| document.getElementById(buttonId) == undefined) {
return;
}
if (document.getElementById(buttonId).dispatchEvent) {
var e = document.createEvent("MouseEvents");
e.initEvent("click", true, true);
document.getElementById(buttonId).dispatchEvent(e);
} else {
document.getElementById(buttonId).click();
}
}
and you can use it like
submitRequest("target-element-id");
None of these answers worked for me for python. I solved by this
a[not(@id='XX')]
Also you can use or condition in your xpath by |
operator. Such as
a[not(@id='XX')]|a[not(@class='YY')]
Sometimes we want element which has no class. So you can do like
a[not(@class)]
The non-greedy regex modifiers are like their greedy counter-parts but with a ?
immediately following them:
* - zero or more
*? - zero or more (non-greedy)
+ - one or more
+? - one or more (non-greedy)
? - zero or one
?? - zero or one (non-greedy)
Use socket
and its gethostname()
functionality. This will get the hostname
of the computer where the Python interpreter is running:
import socket
print(socket.gethostname())
You are missing spring-security-web-3.1.X.RELEASE.jar
from your classpath
Most simplest way is to use a IF(). Yes Mysql allows you to do conditional logic. IF function takes 3 params CONDITION, TRUE OUTCOME, FALSE OUTCOME.
So Logic is
if report.type = 'p'
amount = amount
else
amount = -1*amount
SQL
SELECT
id, IF(report.type = 'P', abs(amount), -1*abs(amount)) as amount
FROM report
You may skip abs() if all no's are +ve only
StringBuilder reduces the number of allocations and assignments, at a cost of extra memory used. Used properly, it can completely remove the need for the compiler to allocate larger and larger strings over and over until the result is found.
string result = "";
for(int i = 0; i != N; ++i)
{
result = result + i.ToString(); // allocates a new string, then assigns it to result, which gets repeated N times
}
vs.
String result;
StringBuilder sb = new StringBuilder(10000); // create a buffer of 10k
for(int i = 0; i != N; ++i)
{
sb.Append(i.ToString()); // fill the buffer, resizing if it overflows the buffer
}
result = sb.ToString(); // assigns once
Here is updated version of @johnny.rodgers
Hope helps someone.
// ie9 ve ie7 return true but never fire, lets remove ie less then 10
if(("onhashchange" in window) && navigator.userAgent.toLowerCase().indexOf('msie') == -1){ // event supported?
window.onhashchange = function(){
var url = window.location.hash.substring(1);
alert(url);
}
}
else{ // event not supported:
var storedhash = window.location.hash;
window.setInterval(function(){
if(window.location.hash != storedhash){
storedhash = window.location.hash;
alert(url);
}
}, 100);
}
Another way is to use a transparent 1x1.png with width: 100%
, height: auto
in a div
and absolutely positioned content within it:
html:
<div>
<img src="1x1px.png">
<h1>FOO</h1>
</div>
css:
div {
position: relative;
width: 50%;
}
img {
width: 100%;
height: auto;
}
h1 {
position: absolute;
top: 10px;
left: 10px;
}
12000 elements is nothing in Python... and actually the number of elements can go as far as the Python interpreter has memory on your system.
Just add min-height:100% and min-width:100% and it will work. I had the same problem. You don't need a 3th wrapper
TL;DR
Use Promise.all
for the parallel function calls, the answer behaviors not correctly when the error occurs.
First, execute all the asynchronous calls at once and obtain all the Promise
objects. Second, use await
on the Promise
objects. This way, while you wait for the first Promise
to resolve the other asynchronous calls are still progressing. Overall, you will only wait for as long as the slowest asynchronous call. For example:
// Begin first call and store promise without waiting
const someResult = someCall();
// Begin second call and store promise without waiting
const anotherResult = anotherCall();
// Now we await for both results, whose async processes have already been started
const finalResult = [await someResult, await anotherResult];
// At this point all calls have been resolved
// Now when accessing someResult| anotherResult,
// you will have a value instead of a promise
JSbin example: http://jsbin.com/xerifanima/edit?js,console
Caveat: It doesn't matter if the await
calls are on the same line or on different lines, so long as the first await
call happens after all of the asynchronous calls. See JohnnyHK's comment.
Update: this answer has a different timing in error handling according to the @bergi's answer, it does NOT throw out the error as the error occurs but after all the promises are executed.
I compare the result with @jonny's tip: [result1, result2] = Promise.all([async1(), async2()])
, check the following code snippet
const correctAsync500ms = () => {_x000D_
return new Promise(resolve => {_x000D_
setTimeout(resolve, 500, 'correct500msResult');_x000D_
});_x000D_
};_x000D_
_x000D_
const correctAsync100ms = () => {_x000D_
return new Promise(resolve => {_x000D_
setTimeout(resolve, 100, 'correct100msResult');_x000D_
});_x000D_
};_x000D_
_x000D_
const rejectAsync100ms = () => {_x000D_
return new Promise((resolve, reject) => {_x000D_
setTimeout(reject, 100, 'reject100msError');_x000D_
});_x000D_
};_x000D_
_x000D_
const asyncInArray = async (fun1, fun2) => {_x000D_
const label = 'test async functions in array';_x000D_
try {_x000D_
console.time(label);_x000D_
const p1 = fun1();_x000D_
const p2 = fun2();_x000D_
const result = [await p1, await p2];_x000D_
console.timeEnd(label);_x000D_
} catch (e) {_x000D_
console.error('error is', e);_x000D_
console.timeEnd(label);_x000D_
}_x000D_
};_x000D_
_x000D_
const asyncInPromiseAll = async (fun1, fun2) => {_x000D_
const label = 'test async functions with Promise.all';_x000D_
try {_x000D_
console.time(label);_x000D_
let [value1, value2] = await Promise.all([fun1(), fun2()]);_x000D_
console.timeEnd(label);_x000D_
} catch (e) {_x000D_
console.error('error is', e);_x000D_
console.timeEnd(label);_x000D_
}_x000D_
};_x000D_
_x000D_
(async () => {_x000D_
console.group('async functions without error');_x000D_
console.log('async functions without error: start')_x000D_
await asyncInArray(correctAsync500ms, correctAsync100ms);_x000D_
await asyncInPromiseAll(correctAsync500ms, correctAsync100ms);_x000D_
console.groupEnd();_x000D_
_x000D_
console.group('async functions with error');_x000D_
console.log('async functions with error: start')_x000D_
await asyncInArray(correctAsync500ms, rejectAsync100ms);_x000D_
await asyncInPromiseAll(correctAsync500ms, rejectAsync100ms);_x000D_
console.groupEnd();_x000D_
})();
_x000D_
Just enter this simple command:
ls -d */
Use the splat operator(*)
By default, * operator prints list separated by space. Use sep
operator to specify the delimiter
print(*sys.path, sep = "\n")
You can use map
:
List<String> names =
personList.stream()
.map(Person::getName)
.collect(Collectors.toList());
EDIT :
In order to combine the Lists of friend names, you need to use flatMap
:
List<String> friendNames =
personList.stream()
.flatMap(e->e.getFriends().stream())
.collect(Collectors.toList());
When Python2.x sees a == b
, it tries the following.
type(b)
is a new-style class, and type(b)
is a subclass of type(a)
, and type(b)
has overridden __eq__
, then the result is b.__eq__(a)
.type(a)
has overridden __eq__
(that is, type(a).__eq__
isn't object.__eq__
), then the result is a.__eq__(b)
.type(b)
has overridden __eq__
, then the result is b.__eq__(a)
.__cmp__
. If it exists, the objects are equal iff it returns zero
.object.__eq__(a, b)
, which is True
iff a
and b
are the same object.If any of the special methods return NotImplemented
, Python acts as though the method didn't exist.
Note that last step carefully: if neither a
nor b
overloads ==
, then a == b
is the same as a is b
.
With the official Material Components library you can use the MaterialButton
applying a Widget.MaterialComponents.Button.Icon
style.
Something like:
<com.google.android.material.button.MaterialButton
android:layout_width="48dp"
android:layout_height="48dp"
style="@style/Widget.MaterialComponents.Button.Icon"
app:icon="@drawable/ic_add"
app:iconSize="24dp"
app:iconPadding="0dp"
android:insetLeft="0dp"
android:insetTop="0dp"
android:insetRight="0dp"
android:insetBottom="0dp"
app:shapeAppearanceOverlay="@style/ShapeAppearanceOverlay.MyApp.Button.Rounded"
/>
Currently the app:iconPadding="0dp"
,android:insetLeft
,android:insetTop
,android:insetRight
,android:insetBottom
attributes are needed to center the icon on the button avoiding extra padding space.
Use the app:shapeAppearanceOverlay
attribute to get rounded corners. In this case you will have a circle.
<style name="ShapeAppearanceOverlay.MyApp.Button.Rounded" parent="">
<item name="cornerFamily">rounded</item>
<item name="cornerSize">50%</item>
</style>
The final result:
array_change_value_case
by continue
function array_change_value_case($array, $case = CASE_LOWER){
if ( ! is_array($array)) return false;
foreach ($array as $key => &$value){
if (is_array($value))
call_user_func_array(__function__, array (&$value, $case ) ) ;
else
$array[$key] = ($case == CASE_UPPER )
? strtoupper($array[$key])
: strtolower($array[$key]);
}
return $array;
}
$arrays = array ( 1 => 'ONE', 2=> 'TWO', 3 => 'THREE',
'FOUR' => array ('a' => 'Ahmed', 'b' => 'basem',
'c' => 'Continue'),
5=> 'FIVE',
array('AbCdeF'));
$change_case = array_change_value_case($arrays, CASE_UPPER);
echo "<pre>";
print_r($change_case);
Array ( [1] => one [2] => two [3] => three [FOUR] => Array ( [a] => ahmed [b] => basem [c] => continue ) [5] => five [6] => Array ( [0] => abcdef ) )
Put this code somewhere in your C++ project:
#ifdef _DEBUG
TCHAR version[50];
sprintf(&version[0], "Version = %d", _MSC_VER);
MessageBox(NULL, (LPCTSTR)szMsg, "Visual Studio", MB_OK | MB_ICONINFORMATION);
#endif
Note that _MSC_VER
symbol is Microsoft specific. Here you can find a list of Visual Studio versions with the value for _MSC_VER
for each version.
If you're looking for the equivalent of PHP's empty
function, check this out:
function empty(mixed_var) {
// example 1: empty(null);
// returns 1: true
// example 2: empty(undefined);
// returns 2: true
// example 3: empty([]);
// returns 3: true
// example 4: empty({});
// returns 4: true
// example 5: empty({'aFunc' : function () { alert('humpty'); } });
// returns 5: false
var undef, key, i, len;
var emptyValues = [undef, null, false, 0, '', '0'];
for (i = 0, len = emptyValues.length; i < len; i++) {
if (mixed_var === emptyValues[i]) {
return true;
}
}
if (typeof mixed_var === 'object') {
for (key in mixed_var) {
// TODO: should we check for own properties only?
//if (mixed_var.hasOwnProperty(key)) {
return false;
//}
}
return true;
}
return false;
}
Here's a quick one-line hack that I occasionally use to temporarily turn on log4j debug logging in a JUnit test:
Logger.getRootLogger().setLevel(Level.DEBUG);
or if you want to avoid adding imports:
org.apache.log4j.Logger.getRootLogger().setLevel(
org.apache.log4j.Level.DEBUG);
Note: this hack doesn't work in log4j2 because setLevel
has been removed from the API, and there doesn't appear to be equivalent functionality.
A simple way of doing this that I found as a comment by @awardak in Brandon Rude's answer:
new Thread( new Runnable() { @Override public void run() {
// Run whatever background code you want here.
} } ).start();
I'm not sure if, or how , this is better than using AsyncTask.execute
but it seems to work for us. Any comments as to the difference would be appreciated.
Thanks, @awardak!
The toString()
implementation of java.util.Date
does not depend on the way the class is imported. It always returns a nice formatted date.
The toString()
you see comes from another class.
Specific import have precedence over wildcard imports.
in this case
import other.Date
import java.util.*
new Date();
refers to other.Date
and not java.util.Date
.
The odd thing is that
import other.*
import java.util.*
Should give you a compiler error stating that the reference to Date is ambiguous because both other.Date
and java.util.Date
matches.
On Mac/Linux, you can easily convert a SVG file to a base64 encoded value for CSS background attribute with this simple bash command:
echo "background: transparent url('data:image/svg+xml;base64,"$(openssl base64 < path/to/file.svg)"') no-repeat center center;"
Tested on Mac OS X. This way you also avoid the URL escaping mess.
Remember that base64 encoding an SVG file increase its size, see css-tricks.com blog post.
Update: In EF 6.2 there is a like operator
Where(obj => DbFunctions.Like(obj.Column , "%expression%")
command = "ps -A | grep 'process_name'"
output = subprocess.check_output(["bash", "-c", command])
Let's say you have a tag someplace on the page which contains your loading message:
<div id='loadingmessage' style='display:none'>
<img src='loadinggraphic.gif'/>
</div>
You can add two lines to your ajax call:
function getData(p){
var page=p;
$('#loadingmessage').show(); // show the loading message.
$.ajax({
url: "loadData.php?id=<? echo $id; ?>",
type: "POST",
cache: false,
data: "&page="+ page,
success : function(html){
$(".content").html(html);
$('#loadingmessage').hide(); // hide the loading message
}
});
For people, who just want to get the current stacktrace to their logs, I would go with:
getLogger().debug("Message", new Throwable());
Cheers
If the number of fields in the CSV is constant then you could do something like this:
select a[1], a[2], a[3], a[4]
from (
select regexp_split_to_array('a,b,c,d', ',')
) as dt(a)
For example:
=> select a[1], a[2], a[3], a[4] from (select regexp_split_to_array('a,b,c,d', ',')) as dt(a);
a | a | a | a
---+---+---+---
a | b | c | d
(1 row)
If the number of fields in the CSV is not constant then you could get the maximum number of fields with something like this:
select max(array_length(regexp_split_to_array(csv, ','), 1))
from your_table
and then build the appropriate a[1], a[2], ..., a[M]
column list for your query. So if the above gave you a max of 6, you'd use this:
select a[1], a[2], a[3], a[4], a[5], a[6]
from (
select regexp_split_to_array(csv, ',')
from your_table
) as dt(a)
You could combine those two queries into a function if you wanted.
For example, give this data (that's a NULL in the last row):
=> select * from csvs;
csv
-------------
1,2,3
1,2,3,4
1,2,3,4,5,6
(4 rows)
=> select max(array_length(regexp_split_to_array(csv, ','), 1)) from csvs;
max
-----
6
(1 row)
=> select a[1], a[2], a[3], a[4], a[5], a[6] from (select regexp_split_to_array(csv, ',') from csvs) as dt(a);
a | a | a | a | a | a
---+---+---+---+---+---
1 | 2 | 3 | | |
1 | 2 | 3 | 4 | |
1 | 2 | 3 | 4 | 5 | 6
| | | | |
(4 rows)
Since your delimiter is a simple fixed string, you could also use string_to_array
instead of regexp_split_to_array
:
select ...
from (
select string_to_array(csv, ',')
from csvs
) as dt(a);
Thanks to Michael for the reminder about this function.
You really should redesign your database schema to avoid the CSV column if at all possible. You should be using an array column or a separate table instead.
You're being mislead by output -- the second approach you're taking actually does what you want, you just aren't believing it. :)
>>> foo = 'baz "\\"'
>>> foo
'baz "\\"'
>>> print(foo)
baz "\"
Incidentally, there's another string form which might be a bit clearer:
>>> print(r'baz "\"')
baz "\"
for localhost,the defaut port is 8080,you can test the link http://localhost:8080 in you browser.if you can see tomcat home page,your tomcat is running
Comparison expressions should each be in their own brackets:
{% if (a == 'foo') or (b == 'bar') %}
...
{% endif %}
Alternative if you are inspecting a single variable and a number of possible values:
{% if a in ['foo', 'bar', 'qux'] %}
...
{% endif %}
One possible C loop would be:
#include <stdio.h>
int main()
{
int c;
while ((c = getchar()) != EOF)
{
/*
** Do something with c, such as check against '\n'
** and increment a line counter.
*/
}
}
For now, I would ignore feof
and similar functions. Exprience shows that it is far too easy to call it at the wrong time and process something twice in the belief that eof hasn't yet been reached.
Pitfall to avoid: using char
for the type of c. getchar
returns the next character cast to an unsigned char
and then to an int
. This means that on most [sane] platforms the value of EOF
and valid "char
" values in c
don't overlap so you won't ever accidentally detect EOF
for a 'normal' char
.
The .NET Data Providers consist of a number of classes used to connect to a data source, execute commands, and return recordsets. The Command Object in ADO.NET provides a number of Execute methods that can be used to perform the SQL queries in a variety of fashions.
A stored procedure is a pre-compiled executable object that contains one or more SQL statements. In many cases stored procedures accept input parameters and return multiple values . Parameter values can be supplied if a stored procedure is written to accept them. A sample stored procedure with accepting input parameter is given below :
CREATE PROCEDURE SPCOUNTRY
@COUNTRY VARCHAR(20)
AS
SELECT PUB_NAME FROM publishers WHERE COUNTRY = @COUNTRY
GO
The above stored procedure is accepting a country name (@COUNTRY VARCHAR(20)) as parameter and return all the publishers from the input country. Once the CommandType is set to StoredProcedure, you can use the Parameters collection to define parameters.
command.CommandType = CommandType.StoredProcedure;
param = new SqlParameter("@COUNTRY", "Germany");
param.Direction = ParameterDirection.Input;
param.DbType = DbType.String;
command.Parameters.Add(param);
The above code passing country parameter to the stored procedure from C# application.
using System;
using System.Data;
using System.Windows.Forms;
using System.Data.SqlClient;
namespace WindowsFormsApplication1
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
private void button1_Click(object sender, EventArgs e)
{
string connetionString = null;
SqlConnection connection ;
SqlDataAdapter adapter ;
SqlCommand command = new SqlCommand();
SqlParameter param ;
DataSet ds = new DataSet();
int i = 0;
connetionString = "Data Source=servername;Initial Catalog=PUBS;User ID=sa;Password=yourpassword";
connection = new SqlConnection(connetionString);
connection.Open();
command.Connection = connection;
command.CommandType = CommandType.StoredProcedure;
command.CommandText = "SPCOUNTRY";
param = new SqlParameter("@COUNTRY", "Germany");
param.Direction = ParameterDirection.Input;
param.DbType = DbType.String;
command.Parameters.Add(param);
adapter = new SqlDataAdapter(command);
adapter.Fill(ds);
for (i = 0; i <= ds.Tables[0].Rows.Count - 1; i++)
{
MessageBox.Show (ds.Tables[0].Rows[i][0].ToString ());
}
connection.Close();
}
}
}
Worth noting that if nothing worked for you, you may have forgotten to escape your path.
For example, this code:
f = open("C:\Some\Path\To\file.csv")
Would result in an error:
SyntaxError: (unicode error) 'unicodeescape' codec can't decode bytes in position 2-3: truncated \UXXXXXXXX escape
To fix, simply do:
f = open("C:\\Some\\Path\\To\\file.csv")
I think what you want is this:
Html.ActionLink(article.Title,
"Login", // <-- Controller Name.
"Item", // <-- ActionMethod
new { id = article.ArticleID }, // <-- Route arguments.
null // <-- htmlArguments .. which are none. You need this value
// otherwise you call the WRONG method ...
// (refer to comments, below).
)
This uses the following method ActionLink signature:
public static string ActionLink(this HtmlHelper htmlHelper,
string linkText,
string controllerName,
string actionName,
object values,
object htmlAttributes)
two arguments have been switched around
Html.ActionLink(article.Title,
"Item", // <-- ActionMethod
"Login", // <-- Controller Name.
new { id = article.ArticleID }, // <-- Route arguments.
null // <-- htmlArguments .. which are none. You need this value
// otherwise you call the WRONG method ...
// (refer to comments, below).
)
This uses the following method ActionLink signature:
public static string ActionLink(this HtmlHelper htmlHelper,
string linkText,
string actionName,
string controllerName,
object values,
object htmlAttributes)
arguments are in the same order as MVC2, however the id value is no longer required:
Html.ActionLink(article.Title,
"Item", // <-- ActionMethod
"Login", // <-- Controller Name.
new { article.ArticleID }, // <-- Route arguments.
null // <-- htmlArguments .. which are none. You need this value
// otherwise you call the WRONG method ...
// (refer to comments, below).
)
This avoids hard-coding any routing logic into the link.
<a href="/Item/Login/5">Title</a>
This will give you the following html output, assuming:
article.Title = "Title"
article.ArticleID = 5
. .
routes.MapRoute(
"Default", // Route name
"{controller}/{action}/{id}", // URL with parameters
new { controller = "Home", action = "Index", id = "" } // Parameter defaults
);
When you run the Windows Command Prompt, and type in python
, it starts the Python interpreter.
Typing it again tries to interpret python
as a variable, which doesn't exist and thus won't work:
Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. All rights reserved.
C:\Users\USER>python
Python 2.7.5 (default, May 15 2013, 22:43:36) [MSC v.1500 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> python
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
NameError: name 'python' is not defined
>>> print("interpreter has started")
interpreter has started
>>> quit() # leave the interpreter, and go back to the command line
C:\Users\USER>
If you're not doing this from the command line, and instead running the Python interpreter (python.exe or IDLE's shell) directly, you are not in the Windows Command Line, and python
is interpreted as a variable, which you have not defined.
The best solution for me was to make
select {
direction: rtl;
}
and then
option {
direction: ltr;
}
again. So there is no change in how the text is read in a screen reader or and no formatting-problem.
in linux , Just go to "/var/lib/mysql" right click and (open as adminstrator), find the folder corresponding to your database name inside mysql folder and delete it. that's it. Database is dropped.
As a response to the two answers which mention DailyRollingFileAppender (sorry, I don't have enough rep to comment on them directly, and I think this needs to be mentioned), I would warn that unfortunately the developers of that class have documented that it exhibits synchronization and data loss, and recommend that alternatives should be pursued for new deployments.
Specifying a non-static position, e.g., position: absolute/relative
on a node means that it will be used as the reference for absolutely positioned elements within it http://jsfiddle.net/E5eEk/1/
See https://developer.mozilla.org/en-US/docs/Learn/CSS/CSS_layout/Positioning#Positioning_contexts
We can change the positioning context — which element the absolutely positioned element is positioned relative to. This is done by setting positioning on one of the element's ancestors.
#outer {_x000D_
min-width: 2000px; _x000D_
min-height: 1000px; _x000D_
background: #3e3e3e; _x000D_
position:relative_x000D_
}_x000D_
_x000D_
#inner {_x000D_
left: 1%; _x000D_
top: 45px; _x000D_
width: 50%; _x000D_
height: auto; _x000D_
position: absolute; _x000D_
z-index: 1;_x000D_
}_x000D_
_x000D_
#inner-inner {_x000D_
background: #efffef;_x000D_
position: absolute; _x000D_
height: 400px; _x000D_
right: 0px; _x000D_
left: 0px;_x000D_
}
_x000D_
<div id="outer">_x000D_
<div id="inner">_x000D_
<div id="inner-inner"></div>_x000D_
</div>_x000D_
</div>
_x000D_
There is no absolute answer to your question, because technology is always bound to be implementation-specific. I am assuming you are communicating in UDP because incoming buffer size does not bring problem to TCP communication.
According to RFC 768, the packet size (header-inclusive) for UDP can range from 8 to 65 515 bytes. So the fail-proof size for incoming buffer is 65 507 bytes (~64KB)
However, not all large packets can be properly routed by network devices, refer to existing discussion for more information:
What is the optimal size of a UDP packet for maximum throughput?
What is the largest Safe UDP Packet Size on the Internet
JavaScript has Function-Level variable scope which means you will have to declare your variable outside $(document).ready()
function.
Or alternatively to make your variable to have global scope, simply dont use var
keyword before it like shown below. However generally this is considered bad practice because it pollutes the global scope but it is up to you to decide.
$(document).ready(function() {
intro = null; // it is in global scope now
To learn more about it, check out:
The best way is by switch
-ing between v.getId(). Having separate anonymous OnClickListener for each Button is taking up more memory. Casting View to Button is unnecessary. Using if-else when switch is possible is slower and harder to read. In Android's source you can often notice comparing the references by if-else:
if (b1 == v) {
// ...
} else if (b2 == v) {
I don't know exactly why they chose this way, but it works too.
Also, what helped me understand this particular scenario that you described is the Promise API documentation, specifically where it explains how the promised returned by the then
method will be resolved differently depending on what the handler fn returns:
if the handler function:
- returns a value, the promise returned by then gets resolved with the returned value as its value;
- throws an error, the promise returned by then gets rejected with the thrown error as its value;
- returns an already resolved promise, the promise returned by then gets resolved with that promise's value as its value;
- returns an already rejected promise, the promise returned by then gets rejected with that promise's value as its value.
- returns another pending promise object, the resolution/rejection of the promise returned by then will be subsequent to the resolution/rejection of the promise returned by the handler. Also, the value of the promise returned by then will be the same as the value of the promise returned by the handler.
For a virtual function you need to provide implementation in the base class. However derived class can override this implementation with its own implementation. Normally , for pure virtual functions implementation is not provided. You can make a function pure virtual with =0
at the end of function declaration. Also, a class containing a pure virtual function is abstract i.e. you can not create a object of this class.
copy *.txt all.txt
This will concatenate all text files of the folder to one text file all.txt
If you have any other type of files, like sql files
copy *.sql all.sql
Garbage collection refers to the process of automatically freeing memory on the heap by deleting objects that are no longer reachable in your program. The heap is a memory which is referred to as the free store, represents a large pool of unused memory allocated to your Java application.
Ken's answer is basically right but I'd like to chime in on the "why would you want to use one over the other?" part of your question.
The base interface you choose for your repository has two main purposes. First, you allow the Spring Data repository infrastructure to find your interface and trigger the proxy creation so that you inject instances of the interface into clients. The second purpose is to pull in as much functionality as needed into the interface without having to declare extra methods.
The Spring Data core library ships with two base interfaces that expose a dedicated set of functionalities:
CrudRepository
- CRUD methodsPagingAndSortingRepository
- methods for pagination and sorting (extends CrudRepository
)The individual store modules (e.g. for JPA or MongoDB) expose store-specific extensions of these base interfaces to allow access to store-specific functionality like flushing or dedicated batching that take some store specifics into account. An example for this is deleteInBatch(…)
of JpaRepository
which is different from delete(…)
as it uses a query to delete the given entities which is more performant but comes with the side effect of not triggering the JPA-defined cascades (as the spec defines it).
We generally recommend not to use these base interfaces as they expose the underlying persistence technology to the clients and thus tighten the coupling between them and the repository. Plus, you get a bit away from the original definition of a repository which is basically "a collection of entities". So if you can, stay with PagingAndSortingRepository
.
The downside of directly depending on one of the provided base interfaces is two-fold. Both of them might be considered as theoretical but I think they're important to be aware of:
Page
or Pageable
in your code anyway. Spring Data is not any different from any other general purpose library like commons-lang or Guava. As long as it provides reasonable benefit, it's just fine.CrudRepository
, you expose a complete set of persistence method at once. This is probably fine in most circumstances as well but you might run into situations where you'd like to gain more fine-grained control over the methods expose, e.g. to create a ReadOnlyRepository
that doesn't include the save(…)
and delete(…)
methods of CrudRepository
.The solution to both of these downsides is to craft your own base repository interface or even a set of them. In a lot of applications I have seen something like this:
interface ApplicationRepository<T> extends PagingAndSortingRepository<T, Long> { }
interface ReadOnlyRepository<T> extends Repository<T, Long> {
// Al finder methods go here
}
The first repository interface is some general purpose base interface that actually only fixes point 1 but also ties the ID type to be Long
for consistency. The second interface usually has all the find…(…)
methods copied from CrudRepository
and PagingAndSortingRepository
but does not expose the manipulating ones. Read more on that approach in the reference documentation.
The repository abstraction allows you to pick the base repository totally driven by you architectural and functional needs. Use the ones provided out of the box if they suit, craft your own repository base interfaces if necessary. Stay away from the store specific repository interfaces unless unavoidable.
I have a use case where I have to iterate through the dict to get the key, value pair, also the index indicating where I am. This is how I do it:
d = {'x': 1, 'y': 2, 'z': 3}
for i, (key, value) in enumerate(d.items()):
print(i, key, value)
Note that the parentheses around the key, value are important, without them, you'd get an ValueError
"not enough values to unpack".
png has a wider color pallete than gif and gif is properitary while png is not. gif can do animations, what normal-png cannot. png-transparency is only supported by browser roughly more recent than IE6, but there is a Javascript fix for that problem. Both support alpha transparency. In general I would say that you should use png for most webgraphics while using jpeg for photos, screenshots, or similiar because png compression does not work too good on thoose.
Changes to Enterprise App Distribution Coming in iOS 9
iOS 9 introduces a new feature to help protect users from installing in-house apps from untrusted sources. While no new app signing or provisioning methods are required, the way your enterprise users manage in-house apps installed on their iOS 9 devices will change.
In-house apps installed using an MDM solution are explicitly trusted and will no longer prompt the user to trust the developer that signed and provisioned the app. If your enterprise app does not use an MDM solution, users who install your app for the first time will be prompted to trust the developer. All users who install your app for the first time will need an internet connection.
Using a new restriction, organizations can limit the apps installed on their devices to the in-house apps that they create. And a new interface in Settings allows users to see all enterprise apps installed from their organization.
Source: Official email sent from [email protected] to existing enterprise app developers.
I have stumbled here twice, and this last time was a unique situation and even though I ditch using copy-item
I wanted to post the solution I used.
Had a list of nothing but files with the full path and in majority of the case the files have no extensions. the -Recurse -Force
option would not work for me so I ditched copy-item
function and fell back to something like below using xcopy as I still wanted to keep it a one liner. Initially I tied with Robocopy but it is apparently looking for a file extension and since many of mine had no extension it considered it a directory.
$filelist = @("C:\Somepath\test\location\here\file","C:\Somepath\test\location\here2\file2")
$filelist | % { echo f | xcopy $_ $($_.Replace("somepath", "somepath_NEW")) }
Hope it helps someone.
<style type="text/css">
#container{
text-align: center;
width: 100%;
height: 200px; /* Set height */
margin: 0px;
padding: 0px;
background-image: url('../assets/images/img.jpg');
background-size: content; /* Scaling down large image to a div */
background-repeat: no-repeat;
background-position: center;
}
</style>
<div id="container>
<!-- Inside container -->
</div>
There might be a fix to <input type="button">
- but if there is, I don't know it.
Otherwise, a good option seems to be to replace it with a carefully styled a
element.
Example: http://jsfiddle.net/Uka5v/
.button {
background-color: #E3E1B8;
padding: 2px 4px;
font: 13px sans-serif;
text-decoration: none;
border: 1px solid #000;
border-color: #aaa #444 #444 #aaa;
color: #000
}
Upsides include that the a
element will style consistently between different (older) versions of Internet Explorer without any extra work, and I think my link looks nicer than that button :)
From the doc for path.resolve
:
The resulting path is normalized and trailing slashes are removed unless the path is resolved to the root directory.
But path.join
keeps trailing slashes
So
__dirname = '/';
path.resolve(__dirname, 'foo/'); // '/foo'
path.join(__dirname, 'foo/'); // '/foo/'
Consider this: I use it to export 20 typed list by same way:
private void Generate<T>()
{
T item = (T)Activator.CreateInstance(typeof(T));
((T)item as DemomigrItemList).Initialize();
Type type = ((T)item as DemomigrItemList).AsEnumerable().FirstOrDefault().GetType();
if (type == null) return;
if (type != typeof(account)) //account is listitem in List<account>
{
((T)item as DemomigrItemList).CreateCSV(type);
}
}
SharePoint lists V: Techniques for managing large lists :
Tutorial By Microsoft
Level: Advanced
Length: 40 - 50 minutes
When a SharePoint list gets large, you might see warnings such as, “This list exceeds the list view threshold,” or “Displaying the newest results below.” Find out why these warnings occur, and learn ways to configure your large list so that it still provides useful information.
After completing this course you will be able to:
How to access screen size or pixel density or aspect ratio in flutter ?
We can access screen size and other like pixel density, aspect ration etc. with helps of MediaQuery.
syntex : MediaQuery.of(context).size.height
I had a similar problem. It turned out, I was including an old header file of the same name from an old folder. I deleted the old file changed the #include directive to point to my new file and all was good.
You can only add folders or jar files to a class loader. So if you have a single class file, you need to put it into the appropriate folder structure first.
Here is a rather ugly hack that adds to the SystemClassLoader at runtime:
import java.io.IOException;
import java.io.File;
import java.net.URLClassLoader;
import java.net.URL;
import java.lang.reflect.Method;
public class ClassPathHacker {
private static final Class[] parameters = new Class[]{URL.class};
public static void addFile(String s) throws IOException {
File f = new File(s);
addFile(f);
}//end method
public static void addFile(File f) throws IOException {
addURL(f.toURL());
}//end method
public static void addURL(URL u) throws IOException {
URLClassLoader sysloader = (URLClassLoader) ClassLoader.getSystemClassLoader();
Class sysclass = URLClassLoader.class;
try {
Method method = sysclass.getDeclaredMethod("addURL", parameters);
method.setAccessible(true);
method.invoke(sysloader, new Object[]{u});
} catch (Throwable t) {
t.printStackTrace();
throw new IOException("Error, could not add URL to system classloader");
}//end try catch
}//end method
}//end class
The reflection is necessary to access the protected method addURL
. This could fail if there is a SecurityManager.
I think you should use the Rails debug options:
logger.debug "Person attributes hash: #{@person.attributes.inspect}"
logger.info "Processing the request..."
logger.fatal "Terminating application, raised unrecoverable error!!!"
https://guides.rubyonrails.org/debugging_rails_applications.html
//in html file
<div class="row">
<div class="col-md-6">
<div class="form-group">
<label for="name">Country</label>
<select class="form-control" formControlName="country" (change)="onCountryChange($event.target.value)">
<option disabled selected value [ngValue]="null"> -- Select Country -- </option>
<option *ngFor="let country of countries" [value]="country.id">{{country.name}}</option>
<div *ngIf="isEdit">
<option></option>
</div>
</select>
</div>
</div>
</div>
<div class="help-block" *ngIf="studentForm.get('country').invalid && studentForm.get('country').touched">
<div *ngIf="studentForm.get('country').errors.required">*country is required</div>
</div>
<div class="row">
<div class="col-md-6">
<div class="form-group">
<label for="name">State</label>
<select class="form-control" formControlName="state" (change)="onStateChange($event.target.value)">
<option disabled selected value [ngValue]="null"> -- Select State -- </option>
<option *ngFor="let state of states" [value]="state.id">{{state.state_name}}</option>
</select>
</div>
</div>
</div>
<div class="help-block" *ngIf="studentForm.get('state').invalid && studentForm.get('state').touched">
<div *ngIf="studentForm.get('state').errors.required">*state is enter code hererequired</div>
</div>
<div class="row">
<div class="col-md-6">
<div class="form-group">
<label for="name">City</label>
<select class="form-control" formControlName="city">
<option disabled selected value [ngValue]="null"> -- Select City -- </option>
<option *ngFor="let city of cities" [value]="city.id" >{{city.city_name}}</option>
</select>
</div>
</div>
</div>
<div class="help-block" *ngIf="studentForm.get('city').invalid && studentForm.get('city').touched">
<div *ngIf="studentForm.get('city').errors.required">*city is required</div>
</div>
//then in component
onCountryChange(countryId:number){
this.studentServive.getSelectedState(countryId).subscribe(resData=>{
this.states = resData;
});
}
onStateChange(stateId:number){
this.studentServive.getSelectedCity(stateId).subscribe(resData=>{
this.cities = resData;
});
}`enter code here`
Tests
On the Tests
class we will add an @XmlRootElement
annotation. Doing this will let your JAXB implementation know that when a document starts with this element that it should instantiate this class. JAXB is configuration by exception, this means you only need to add annotations where your mapping differs from the default. Since the testData
property differs from the default mapping we will use the @XmlElement
annotation. You may find the following tutorial helpful: http://wiki.eclipse.org/EclipseLink/Examples/MOXy/GettingStarted
package forum11221136;
import javax.xml.bind.annotation.*;
@XmlRootElement
public class Tests {
TestData testData;
@XmlElement(name="test-data")
public TestData getTestData() {
return testData;
}
public void setTestData(TestData testData) {
this.testData = testData;
}
}
TestData
On this class I used the @XmlType
annotation to specify the order in which the elements should be ordered in. I added a testData
property that appeared to be missing. I also used an @XmlElement
annotation for the same reason as in the Tests
class.
package forum11221136;
import java.util.List;
import javax.xml.bind.annotation.*;
@XmlType(propOrder={"title", "book", "count", "testData"})
public class TestData {
String title;
String book;
String count;
List<TestData> testData;
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getBook() {
return book;
}
public void setBook(String book) {
this.book = book;
}
public String getCount() {
return count;
}
public void setCount(String count) {
this.count = count;
}
@XmlElement(name="test-data")
public List<TestData> getTestData() {
return testData;
}
public void setTestData(List<TestData> testData) {
this.testData = testData;
}
}
Demo
Below is an example of how to use the JAXB APIs to read (unmarshal) the XML and populate your domain model and then write (marshal) the result back to XML.
package forum11221136;
import java.io.File;
import javax.xml.bind.*;
public class Demo {
public static void main(String[] args) throws Exception {
JAXBContext jc = JAXBContext.newInstance(Tests.class);
Unmarshaller unmarshaller = jc.createUnmarshaller();
File xml = new File("src/forum11221136/input.xml");
Tests tests = (Tests) unmarshaller.unmarshal(xml);
Marshaller marshaller = jc.createMarshaller();
marshaller.setProperty(Marshaller.JAXB_FORMATTED_OUTPUT, true);
marshaller.marshal(tests, System.out);
}
}
I wanted to throw a 'normal' 404 for any logged in user that isn't an admin, so I ended up writing something like this in Rails 5:
class AdminController < ApplicationController
before_action :blackhole_admin
private
def blackhole_admin
return if current_user.admin?
raise ActionController::RoutingError, 'Not Found'
rescue ActionController::RoutingError
render file: "#{Rails.root}/public/404", layout: false, status: :not_found
end
end
var isWin64 = process.env.hasOwnProperty('ProgramFiles(x86)');
AMD
CommonJS:
Example
upper.js file
exports.uppercase = str => str.toUpperCase()
main.js file
const uppercaseModule = require('uppercase.js')
uppercaseModule.uppercase('test')
Summary
Resources:
Initialize DataTable:
DataTable dt = new DataTable();
dt.Columns.Add("id", typeof(String));
dt.Columns.Add("name", typeof(String));
for (int i = 0; i < 5; i++)
{
string index = i.ToString();
dt.Rows.Add(new object[] { index, "name" + index });
}
Query itself:
IList<Class1> items = dt.AsEnumerable().Select(row =>
new Class1
{
id = row.Field<string>("id"),
name = row.Field<string>("name")
}).ToList();
I was having trouble with the not (~) symbol as well, so here's another way from another StackOverflow thread:
df[df["col"].str.contains('this|that')==False]
If you are looking for pre-written code that is well maintained, use the function sympy.ntheory.primefactors from SymPy.
It returns a sorted list of prime factors of n
.
>>> from sympy.ntheory import primefactors
>>> primefactors(6008)
[2, 751]
Pass the list to max()
to get the biggest prime factor.
In case you want the prime factors of n
and also the multiplicities of each of them, use sympy.ntheory.factorint.
Given a positive integer
n
,factorint(n)
returns a dict containing the prime factors ofn
as keys and their respective multiplicities as values.
>>> from sympy.ntheory import factorint
>>> factorint(6008) # 6008 = (2**3) * (751**1)
{2: 3, 751: 1}
The code is tested against Python 3.6.9 and SymPy 1.1.1.
You can simply do the following inside your TR loop:
$(this).find('td').each (function() {
// do your cool stuff
});
Something like this:
NSTimer *timer;
timer = [NSTimer scheduledTimerWithTimeInterval: 0.5
target: self
selector: @selector(handleTimer:)
userInfo: nil
repeats: YES];
Hey Its working for me..
$shell = New-Object -ComObject shell.application
$zip = $shell.NameSpace("put ur zip file path here")
foreach ($item in $zip.items()) {
$shell.Namespace("destination where files need to unzip").CopyHere($item)
}
I've had a LOT of trouble with pretty photo and IE9. I also had issues with fancybox in IE.
For youtube.com, I'm having a lot of luck with CeeBox.
http://catcubed.com/2008/12/23/ceebox-a-thickboxvideobox-mashup/
If you need direct access:
WScript.Arguments.Item(0)
WScript.Arguments.Item(1)
...
Do not use any service similar to https://www.diawi.com/ as it can potentially have huge security implications. Using this kind of process and with some clever coding skills, a third party can inject extra stuff in you application. And they are basically charging you for something that you can do yourself.
In iTunes 12.7.x, it is still possible to install an ipa directly on a device with a simple drag-n-drop. Look at @ganesh ubale' solution here or the other answers at https://stackoverflow.com/a/46520816/609862 or https://stackoverflow.com/a/46229114/609862.
The Apple developer web site also have detailed information about how to configure a web site for installing an IPA wirelessly (by simply sharing the download link).
If you are working with Maven and have this problem, check the repository server (for example nexus server), if the artifact is there. Sometimes, they can change the name of the artifact and you try to get the artifact with its old name.
The accepted answer by @Meherzad only works if the data is in a particular order. It happens to work with the data from the OP question. In my case, I had to modify it to work with my data.
Note This only works when every record's "id" (col1 in the question) has a value GREATER THAN that record's "parent id" (col3 in the question). This is often the case, because normally the parent will need to be created first. However if your application allows changes to the hierarchy, where an item may be re-parented somewhere else, then you cannot rely on this.
This is my query in case it helps someone; note it does not work with the given question because the data does not follow the required structure described above.
select t.col1, t.col2, @pv := t.col3 col3
from (select * from table1 order by col1 desc) t
join (select @pv := 1) tmp
where t.col1 = @pv
The difference is that table1
is being ordered by col1
so that the parent will be after it (since the parent's col1
value is lower than the child's).
Since Ant 1.8.0 there's apparently also resourceexists
From http://ant.apache.org/manual/Tasks/conditions.html
Tests a resource for existance. since Ant 1.8.0
The actual resource to test is specified as a nested element.
An example:
<resourceexists> <file file="${file}"/> </resourceexists>
I was about rework the example from the above good answer to this question, and then I found this
As of Ant 1.8.0, you may instead use property expansion; a value of true (or on or yes) will enable the item, while false (or off or no) will disable it. Other values are still assumed to be property names and so the item is enabled only if the named property is defined.
Compared to the older style, this gives you additional flexibility, because you can override the condition from the command line or parent scripts:
<target name="-check-use-file" unless="file.exists"> <available property="file.exists" file="some-file"/> </target> <target name="use-file" depends="-check-use-file" if="${file.exists}"> <!-- do something requiring that file... --> </target> <target name="lots-of-stuff" depends="use-file,other-unconditional-stuff"/>
from the ant manual at http://ant.apache.org/manual/properties.html#if+unless
Hopefully this example is of use to some. They're not using resourceexists, but presumably you could?.....
We call it the "ant" menu. Guess it was a good time to change since everyone had just gotten used to the hamburger.
if {le_gur_bond.gur1}="" or IsNull({le_gur_bond.gur1}) Then
""
else
"and " + {le_gur_bond.gur2} + " of "+ {le_gur_bond.grr_2_address2}
I had the same problem 2 years ago and I solved it in the following way:
1) I build my projects with makefiles, not managed by eclipse 2) I use a SAMBA connection to edit the files inside Eclipse 3) Building the project: Eclipse calles a "local" make with a makefile which opens a SSH connection to the Linux Host. On the SSH command line you can give parameters which are executed on the Linux host. I use for that parameter a makeit.sh shell script which call the "real" make on the linux host. The different targets for building you can give also by parameters from the local makefile --> makeit.sh --> makefile on linux host.
After the latest automatic Java update, I could not run Java from the command prompt.
My path variable had 'C:\ProgramData\Oracle\Java\javapath;'
I could not cd into 'C:\ProgramData\Oracle\Java\javapath;' from the command prompt window, since it did not exist.
I removed C:\ProgramData\Oracle\Java\javapath;' from the path variable and replaced it with 'C:\Program Files\Java\jre1.8.0_141\bin;'
Yes, make the shortcut's path
%comspec% /k <command>
where
%comspec%
is the environment variable for cmd.exe's full path, equivalent to C:\Windows\System32\cmd.exe
on most (if not all) Windows installs/k
keeps the window open after the command has run, this may be replaced with /c
if you want the window to close once the command is finished running<command>
is the command you wish to runExtracts myArchive.tar to /destinationDirectory
Commands:
cd /destinationDirectory
pax -rv -f myArchive.tar -s ',^/,,'
Use these plugins to optimize your production build:
new webpack.optimize.CommonsChunkPlugin('common'),
new webpack.optimize.DedupePlugin(),
new webpack.optimize.UglifyJsPlugin(),
new webpack.optimize.AggressiveMergingPlugin()
I recently came to know about compression-webpack-plugin which gzips your output bundle to reduce its size. Add this as well in the above listed plugins list to further optimize your production code.
new CompressionPlugin({
asset: "[path].gz[query]",
algorithm: "gzip",
test: /\.js$|\.css$|\.html$/,
threshold: 10240,
minRatio: 0.8
})
Server side dynamic gzip compression is not recommended for serving static client-side files because of heavy CPU usage.
add this in web.config file
<configuration>
<appSettings>
<add key="ConnectionString" value="Your connection string which contains database id and password"/>
</appSettings>
</configuration>
.cs file
public ConnectionObjects()
{
string connectionstring= ConfigurationManager.AppSettings["ConnectionString"].ToString();
}
Hope this helps.
Here's what i did:
SomeActivity.java
@Override
public void onBackPressed() {
Intent newIntent = new Intent(this,QuitAppActivity.class);
newIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP|Intent.FLAG_ACTIVITY_CLEAR_TASK | Intent.FLAG_ACTIVITY_NEW_TASK);
startActivity(newIntent);
finish();
}
QuitAppActivity.java
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
finish();
}
Basically what you did is cleared all activities from the stack and launch QuitAppActivity
, that will finish the task.
The data series names are defined by the column headers. Add the names to the column headers that you would like to use as titles for each of your data series, select all of the data (including the headers), then re-generate your graph. The names in the headers should then appear as the names in the legend for each series.
I found this question looking for solution about how to send post request from java client to Google Endpoints. Above answers, very likely correct, but not work in case of Google Endpoints.
Solution for Google Endpoints.
Content type header must be set to "application/json".
post("http://localhost:8888/_ah/api/langapi/v1/createLanguage",
"{\"language\":\"russian\", \"description\":\"dsfsdfsdfsdfsd\"}");
public static void post(String url, String json ) throws Exception{
String charset = "UTF-8";
URLConnection connection = new URL(url).openConnection();
connection.setDoOutput(true); // Triggers POST.
connection.setRequestProperty("Accept-Charset", charset);
connection.setRequestProperty("Content-Type", "application/json;charset=" + charset);
try (OutputStream output = connection.getOutputStream()) {
output.write(json.getBytes(charset));
}
InputStream response = connection.getInputStream();
}
It sure can be done using HttpClient as well.
var mysql = require('mysql');
var pool = mysql.createPool({
host : 'yourip',
port : 'yourport',
user : 'dbusername',
password : 'dbpwd',
database : 'database schema name',
dateStrings: true,
multipleStatements: true
});
// TODO - if any pool issues need to try this link for connection management
// https://stackoverflow.com/questions/18496540/node-js-mysql-connection-pooling
module.exports = function(qry, qrytype, msg, callback) {
if(qrytype != 'S') {
console.log(qry);
}
pool.getConnection(function(err, connection) {
if(err) {
if(connection)
connection.release();
throw err;
}
// Use the connection
connection.query(qry, function (err, results, fields) {
connection.release();
if(err) {
callback('E#connection.query-Error occurred.#'+ err.sqlMessage);
return;
}
if(qrytype==='S') {
//for Select statement
// setTimeout(function() {
callback(results);
// }, 500);
} else if(qrytype==='N'){
let resarr = results[results.length-1];
let newid= '';
if(resarr.length)
newid = resarr[0]['@eid'];
callback(msg + newid);
} else if(qrytype==='U'){
//let ret = 'I#' + entity + ' updated#Updated rows count: ' + results[1].changedRows;
callback(msg);
} else if(qrytype==='D'){
//let resarr = results[1].affectedRows;
callback(msg);
}
});
connection.on('error', function (err) {
connection.release();
callback('E#connection.on-Error occurred.#'+ err.sqlMessage);
return;
});
});
}
This is what I have used in the past.
html, body {
height: 100%;
overflow: auto;
}
Also in the iframe
add the following style
border: 0; position:fixed; top:0; left:0; right:0; bottom:0; width:100%; height:100%
If you have just a pair of brackets ( []
) in your string, you can use indexOf()
:
String str = "ABC[ This is the text to be extracted ]";
String result = str.substring(str.indexOf("[") + 1, str.indexOf("]"));
If you're using ZLib in your project, then you need to find :
#if 1
in zconf.h and replace(uncomment) it with :
#if HAVE_UNISTD_H /* ...the rest of the line
If it isn't ZLib I guess you should find some alternative way to do this. GL.
When using MVC, try using ViewBag. The best way to take input from textbox and displaying in View.
Instance variable is the variable declared inside a class, but outside a method: something like:
class IronMan {
/** These are all instance variables **/
public String realName;
public String[] superPowers;
public int age;
/** Getters and setters here **/
}
Now this IronMan Class can be instantiated in another class to use these variables. Something like:
class Avengers {
public static void main(String[] a) {
IronMan ironman = new IronMan();
ironman.realName = "Tony Stark";
// or
ironman.setAge(30);
}
}
This is how we use the instance variables. Shameless plug: This example was pulled from this free e-book here here.
The year()
function just retrieves the year component of the underlying Date
object, so it returns a number.
Calling format('YYYY')
will invoke moment's string formatting functions, which will parse the format string supplied, and build a new string containing the appropriate data. Since you only are passing YYYY
, then the result will be a string containing the year.
If all you need is the year, then use the year()
function. It will be faster, as there is less work to do.
Do note that while years are the same in this regard, months are not! Calling format('M')
will return months in the range 1-12. Calling month()
will return months in the range 0-11. This is due to the same behavior of the underlying Date
object.
top
object makes more sense inside frames. Inside a frame, window
refers to current frame's window while top
refers to the outermost window that contains the frame(s). So:
window.location.href = 'somepage.html';
means loading somepage.html
inside the frame.
top.location.href = 'somepage.html';
means loading somepage.html
in the main browser window.
Yes I got the trick.
public void onClick(View v) {
if( Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH ){
imgDisplay.setSystemUiVisibility( View.SYSTEM_UI_FLAG_HIDE_NAVIGATION );
}
else if( Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB )
imgDisplay.setSystemUiVisibility( View.STATUS_BAR_HIDDEN );
else{}
}
But it didn't solve my problem completely. I want to hide the horizontal scrollview too, which is in front of the imageView (below), which can't be hidden in this.
-- Declare the text we want to search for
DECLARE @Text nvarchar(4000);
SET @Text = 'employee';
-- Get the schema name, table name, and table type for:
-- Table names
SELECT
TABLE_SCHEMA AS 'Object Schema'
,TABLE_NAME AS 'Object Name'
,TABLE_TYPE AS 'Object Type'
,'Table Name' AS 'TEXT Location'
FROM INFORMATION_SCHEMA.TABLES
WHERE TABLE_NAME LIKE '%'+@Text+'%'
UNION
--Column names
SELECT
TABLE_SCHEMA AS 'Object Schema'
,COLUMN_NAME AS 'Object Name'
,'COLUMN' AS 'Object Type'
,'Column Name' AS 'TEXT Location'
FROM INFORMATION_SCHEMA.COLUMNS
WHERE COLUMN_NAME LIKE '%'+@Text+'%'
UNION
-- Function or procedure bodies
SELECT
SPECIFIC_SCHEMA AS 'Object Schema'
,ROUTINE_NAME AS 'Object Name'
,ROUTINE_TYPE AS 'Object Type'
,ROUTINE_DEFINITION AS 'TEXT Location'
FROM INFORMATION_SCHEMA.ROUTINES
WHERE ROUTINE_DEFINITION LIKE '%'+@Text+'%'
AND (ROUTINE_TYPE = 'function' OR ROUTINE_TYPE = 'procedure');
Component code:
import { Component } from "@angular/core";
@Component({
templateUrl:"home.html"
})
export class HomePage {
public items: Array<string>;
constructor() {
this.items = ["item1", "item2", "item3"]
}
public open(event, item) {
alert('Open ' + item);
}
}
View:
<ion-header>
<ion-navbar primary>
<ion-title>
<span>My App</span>
</ion-title>
</ion-navbar>
</ion-header>
<ion-content>
<ion-list>
<ion-item *ngFor="let item of items" (click)="open($event, item)">
{{ item }}
</ion-item>
</ion-list>
</ion-content>
As you can see in the code, I'm declaring the click handler like this (click)="open($event, item)"
and sending both the event and the item (declared in the *ngFor
) to the open()
method (declared in the component code).
If you just want to show the item and you don't need to get info from the event, you can just do (click)="open(item)"
and modify the open
method like this public open(item) { ... }
You can always use strtotime to minus the number of days from the current date:
$users = Users::where('status_id', 'active')
->where( 'created_at', '>', date('Y-m-d', strtotime("-30 days"))
->get();
SQL> select substr('999123456789', greatest (-9, -length('999123456789')), 9) as value from dual;
VALUE
---------
123456789
SQL> select substr('12345', greatest (-9, -length('12345')), 9) as value from dual;
VALUE
----
12345
The call to greatest (-9, -length(string))
limits the starting offset either 9 characters left of the end or the beginning of the string.
It is specific from your driver. You need to supply a parameter in your Java program to tell it the time zone you want to use.
java -Duser.timezone="America/New_York" GetCurrentDateTimeZone
Further this:
to_char(new_time(sched_start_time, 'CURRENT_TIMEZONE', 'NEW_TIMEZONE'), 'MM/DD/YY HH:MI AM')
May also be of value in handling the conversion properly. Taken from here
This is due to using obsolete mysql-connection-java version, your MySQl is updated but not your MySQL jdbc Driver, you can update your connection jar from the official site Official MySQL Connector site. Good Luck.
Some of the other answers return an actual string whereas I had more need to know the actual index int. And the answers that do that seem to over-complicate things. Using some of the other answers as inspiration, I did the following...
First, I created a function:
CREATE FUNCTION [dbo].[LastIndexOf] (@stringToFind varchar(max), @stringToSearch varchar(max))
RETURNS INT
AS
BEGIN
RETURN (LEN(@stringToSearch) - CHARINDEX(@stringToFind,REVERSE(@stringToSearch))) + 1
END
GO
Then, in your query you can simply do this:
declare @stringToSearch varchar(max) = 'SomeText: SomeMoreText: SomeLastText'
select dbo.LastIndexOf(':', @stringToSearch)
The above should return 23 (the last index of ':')
Hope this made it a little easier for someone!
Some Linux distributions such as Arch Linux have Node.js in their package repositories. On such systems it is better to use a standard package update procedure, such as pacman -Suy
or analogous apt-get
or yum
commands.
As of now (Nov 2016) EPEL7 offers a pretty recent version of Node.js (6.9.1 which is an up-to-date LTS version offered on the Node.js home page). So on CentOS 7 and derivatives you can just add EPEL repository by yum install epel-release
and yum install nodejs
.
CentOS 6/EPEL6 has 0.10.x which isn't supported upstream since Oct 2016.
The best solution if you don't care about staging modified files is to use git add -u
as said by mshameers and/or pb2q.
If you just want to remove deleted files, but not stage any modified ones, I think you should use the ls-files
argument with the --deleted
option (no need to use regex or other complex args/options) :
git ls-files --deleted | xargs git rm
For Python 3.x
import urllib.request
from urllib.error import HTTPError
try:
urllib.request.urlretrieve(url, fullpath)
except urllib.error.HTTPError as err:
print(err.code)
You need to click to the project Open Module Settings and change the path of your JDK, if in the file POM you use jdk 1.8, configure jdk 1.8 with correct path.
git diff --stat commit1 commit2
EDIT: You have to specify the commits as well (without parameters it compares the working directory against the index). E.g.
git diff --stat HEAD^ HEAD
to compare the parent of HEAD
with HEAD
.
in resources/views/layouts/app.blade.php file
<script type="text/javascript">
var baseUrl = '<?=url('');?>';
</script>
if the other div is sibling/child, or any combination of, of the parent yes
.showme{ _x000D_
display: none;_x000D_
}_x000D_
.showhim:hover .showme{_x000D_
display : block;_x000D_
}_x000D_
.showhim:hover .hideme{_x000D_
display : none;_x000D_
}_x000D_
.showhim:hover ~ .hideme2{ _x000D_
display:none;_x000D_
}
_x000D_
<div class="showhim">_x000D_
HOVER ME_x000D_
<div class="showme">hai</div> _x000D_
<div class="hideme">bye</div>_x000D_
</div>_x000D_
<div class="hideme2">bye bye</div>
_x000D_
In my case, same error was coming with JSP. This is how I got to the root of this issue: I went to the Network tab and clearly saw that the browser request to fetch the css was returning response header having "Content-type" : "text/html". I opened another tab and manually hit the request to fetch the css. It ended up returning a html log in form. Turns out that my web application had a url mapping for path = /
Tomcat servlet entry : (@WebServlet({ "/, /index", })
. So, any unmatching request URLs were somehow being matched to /
and the corresponding servlet was returning a Log in html form. I fixed it by removing the mapping to /
Also, the tomcat configuration wrt handling css MIME-TYPE was already present.
You can extend the accepted answer with a default value to avoid exceptions:
public static T ParseEnum<T>(string value, T defaultValue) where T : struct
{
try
{
T enumValue;
if (!Enum.TryParse(value, true, out enumValue))
{
return defaultValue;
}
return enumValue;
}
catch (Exception)
{
return defaultValue;
}
}
Then you call it like:
StatusEnum MyStatus = EnumUtil.ParseEnum("Active", StatusEnum.None);
If the default value is not an enum the Enum.TryParse would fail and throw an exception which is catched.
After years of using this function in our code on many places maybe it's good to add the information that this operation costs performance!
Its very simple:
For ObjC:
NSString *string1 = @"This is";
NSString *string2 = @"Swift Language";
ForSwift:
let string1 = "This is"
let string2 = "Swift Language"
For ObjC AppendString:
NSString *appendString=[NSString stringWithFormat:@"%@ %@",string1,string2];
For Swift AppendString:
var appendString1 = "\(string1) \(string2)"
var appendString2 = string1+string2
Result:
print("APPEND STRING 1:\(appendString1)")
print("APPEND STRING 2:\(appendString2)")
Complete Code In Swift:
let string1 = "This is"
let string2 = "Swift Language"
var appendString = "\(string1) \(string2)"
var appendString1 = string1+string2
print("APPEND STRING1:\(appendString1)")
print("APPEND STRING2:\(appendString2)")
Yes, this is confusing...
According to this blog post, it looks like this is an omission from WPF.
To make it work you need to use a style:
<Border Name="ClearButtonBorder" Grid.Column="1" CornerRadius="0,3,3,0">
<Border.Style>
<Style>
<Setter Property="Border.Background" Value="Blue"/>
<Style.Triggers>
<Trigger Property="Border.IsMouseOver" Value="True">
<Setter Property="Border.Background" Value="Green" />
</Trigger>
</Style.Triggers>
</Style>
</Border.Style>
<TextBlock HorizontalAlignment="Center" VerticalAlignment="Center" Text="X" />
</Border>
I guess this problem isn't that common as most people tend to factor out this sort of thing into a style, so it can be used on multiple controls.
Code:
using System;
using System.Diagnostics;
namespace playSound
{
class Program
{
public static void Main(string[] args)
{
Console.WriteLine(args[0]);
Process amixerMediaProcess = new Process();
amixerMediaProcess.StartInfo.CreateNoWindow = false;
amixerMediaProcess.StartInfo.UseShellExecute = false;
amixerMediaProcess.StartInfo.ErrorDialog = false;
amixerMediaProcess.StartInfo.RedirectStandardOutput = false;
amixerMediaProcess.StartInfo.RedirectStandardInput = false;
amixerMediaProcess.StartInfo.RedirectStandardError = false;
amixerMediaProcess.EnableRaisingEvents = true;
amixerMediaProcess.StartInfo.Arguments = string.Format("{0}","-ssh username@"+args[0]+" -pw password -m commands.txt");
amixerMediaProcess.StartInfo.FileName = "plink.exe";
amixerMediaProcess.Start();
Console.Write("Presskey to continue . . . ");
Console.ReadKey(true);
}
}
}
Sample commands.txt:
ps
Due to the locking implementation issues, MySQL
does not allow referencing the affected table with DELETE
or UPDATE
.
You need to make a JOIN
here instead:
DELETE gc.*
FROM guide_category AS gc
LEFT JOIN
guide AS g
ON g.id_guide = gc.id_guide
WHERE g.title IS NULL
or just use a NOT IN
:
DELETE
FROM guide_category AS gc
WHERE id_guide NOT IN
(
SELECT id_guide
FROM guide
)
What i did was to uninstall and install the "^0.13.0". I confirm/ support this last answer. It worked for me as well. I had uninstall version "^0.800.0" and installed the "^0.13.0". rebuild your project it will work fine.
You could have them semi-colon delimited in a single value, e.g.
App.config
<add key="paths" value="C:\test1;C:\test2;C:\test3" />
C#
var paths = new List<string>(ConfigurationManager.AppSettings["paths"].Split(new char[] { ';' }));
StudentList studentList = mapper.readValue(jsonString,StudentList.class);
Change this to this one
StudentList studentList = mapper.readValue(jsonString, new TypeReference<List<Student>>(){});
create a list like :-
this.xyzlist = [
{
id: 1,
value: 'option1'
},
{
id: 2,
value: 'option2'
}
];
Html :-
<div class="checkbox" *ngFor="let list of xyzlist">
<label>
<input formControlName="interestSectors" type="checkbox" value="{{list.id}}" (change)="onCheckboxChange(list,$event)">{{list.value}}</label>
</div>
then in it's component ts :-
onCheckboxChange(option, event) {
if(event.target.checked) {
this.checkedList.push(option.id);
} else {
for(var i=0 ; i < this.xyzlist.length; i++) {
if(this.checkedList[i] == option.id) {
this.checkedList.splice(i,1);
}
}
}
console.log(this.checkedList);
}
The best option is to use INSERT...SELECT statement in mysql.
Standard letter-based representations of date parts are great, except the fact they're not so intuitive. The much more convenient way is to identify basic abstractions and a number of specific implementations. Besides, with this approach, you can benefir from autocompletion.
Since we're talking about datetimes here, it seems plausible that the basic abstraction is ISO8601DateTime
. One of the specific implementations is current datetime, the one you need when a makes a request to your backend, hence Now()
class. Second one which is of some use for you is a datetime adjusted to some timezone. Not surprisingly, it's called AdjustedAccordingToTimeZone
. And finally, you need a day of the week in a passed datetime's timezone: there is a LocalDayOfWeek
class for that. So the code looks like the following:
(new LocalDayOfWeek(
new AdjustedAccordingToTimeZone(
new Now(),
new TimeZoneFromString($_POST['timezone'])
)
))
->value();
For more about this approach, take a look here.
The code below demonstrates on how to do this.
var http = new XMLHttpRequest();
var url = 'get_data.php';
var params = 'orem=ipsum&name=binny';
http.open('POST', url, true);
//Send the proper header information along with the request
http.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
http.onreadystatechange = function() {//Call a function when the state changes.
if(http.readyState == 4 && http.status == 200) {
alert(http.responseText);
}
}
http.send(params);
In case you have/create an object you can turn it into params using the following code, i.e:
var params = new Object();
params.myparam1 = myval1;
params.myparam2 = myval2;
// Turn the data object into an array of URL-encoded key/value pairs.
let urlEncodedData = "", urlEncodedDataPairs = [], name;
for( name in params ) {
urlEncodedDataPairs.push(encodeURIComponent(name)+'='+encodeURIComponent(params[name]));
}
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Swingtest extends JFrame implements ActionListener
{
JTextField txtdata;
JButton calbtn = new JButton("Calculate");
public Swingtest()
{
JPanel myPanel = new JPanel();
add(myPanel);
myPanel.setLayout(new GridLayout(3, 2));
myPanel.add(calbtn);
calbtn.addActionListener(this);
txtdata = new JTextField();
myPanel.add(txtdata);
}
public void actionPerformed(ActionEvent e)
{
if (e.getSource() == calbtn) {
String data = txtdata.getText(); //perform your operation
System.out.println(data);
}
}
public static void main(String args[])
{
Swingtest g = new Swingtest();
g.setLocation(10, 10);
g.setSize(300, 300);
g.setVisible(true);
}
}
now its working
I think you might be able to use the ExpandProperty
parameter of Select-Object
.
For example, to get the list of the current directory and just have the Name property displayed, one would do the following:
ls | select -Property Name
This is still returning DirectoryInfo or FileInfo objects. You can always inspect the type coming through the pipeline by piping to Get-Member (alias gm
).
ls | select -Property Name | gm
So, to expand the object to be that of the type of property you're looking at, you can do the following:
ls | select -ExpandProperty Name
In your case, you can just do the following to have a variable be an array of strings, where the strings are the Name property:
$objects = ls | select -ExpandProperty Name
In Java, you can use the Collection
interface's removeAll
method.
// Create a couple ArrayList objects and populate them
// with some delicious fruits.
Collection firstList = new ArrayList() {{
add("apple");
add("orange");
}};
Collection secondList = new ArrayList() {{
add("apple");
add("orange");
add("banana");
add("strawberry");
}};
// Show the "before" lists
System.out.println("First List: " + firstList);
System.out.println("Second List: " + secondList);
// Remove all elements in firstList from secondList
secondList.removeAll(firstList);
// Show the "after" list
System.out.println("Result: " + secondList);
The above code will produce the following output:
First List: [apple, orange]
Second List: [apple, orange, banana, strawberry]
Result: [banana, strawberry]
It's a generics literal. It means that you don't know the type of class this Class
instance is representing, but you are still using the generic version.
Class<Foo>
. That way you can create a new instance, for example, without casting: Foo foo = clazz.newInstance();
Your question is ambiguous; the first two sentences taken together imply that you believe that space and "period" are non-ASCII characters. This is incorrect. All chars such that ord(char) <= 127 are ASCII characters. For example, your function excludes these characters !"#$%&\'()*+,-./ but includes several others e.g. []{}.
Please step back, think a bit, and edit your question to tell us what you are trying to do, without mentioning the word ASCII, and why you think that chars such that ord(char) >= 128 are ignorable. Also: which version of Python? What is the encoding of your input data?
Please note that your code reads the whole input file as a single string, and your comment ("great solution") to another answer implies that you don't care about newlines in your data. If your file contains two lines like this:
this is line 1
this is line 2
the result would be 'this is line 1this is line 2'
... is that what you really want?
A greater solution would include:
onlyascii
recognition that a filter function merely needs to return a truthy value if the argument is to be retained:
def filter_func(char):
return char == '\n' or 32 <= ord(char) <= 126
# and later:
filtered_data = filter(filter_func, data).lower()
max_connections
You can change max_connections
while MySQL is running via SET
:
mysql> SET GLOBAL max_connections = 5000;
Query OK, 0 rows affected (0.00 sec)
mysql> SHOW VARIABLES LIKE "max_connections";
+-----------------+-------+
| Variable_name | Value |
+-----------------+-------+
| max_connections | 5000 |
+-----------------+-------+
1 row in set (0.00 sec)
timeout
relatedI had never seen your error message before, so I googled. probably, you are using Connector/Net. Connector/Net Manual says there is max connection pool size. (default is 100) see table 22.21.
I suggest that you increase this value to 100k or disable connection pooling Pooling=false
he has two questions.
Q1 - what happens if I disable pooling
Slow down making DB connection. connection pooling
is a mechanism that use already made DB connection. cost of Making new connection is high. http://en.wikipedia.org/wiki/Connection_pool
Q2 - Can the value of pooling be increased or the maximum is 100?
you can increase but I'm sure what is MAX value, maybe max_connections
in my.cnf
My suggestion is that do not turn off Pooling, increase value by 100 until there is no connection error.
If you have Stress Test tool like JMeter
you can test youself.
There are two possibilities, both from Quest Software, TOAD & SQL Navigator:
Here is the TOAD Freeware download: http://www.toadworld.com/Downloads/FreewareandTrials/ToadforOracleFreeware/tabid/558/Default.aspx
And the SQL Navigator (trial version): http://www.quest.com/sql-navigator/software-downloads.aspx
<table style="width:100%;">
<tbody ><tr><td align="center">
<img src="axe.JPG" />
</td>
</tr>
</tbody>
</table>
or
td
{
text-align:center;
}
in the CSS file
My apache listens to 2 different ports,
Listen 8080
Listen 80
I use the 80 when i want a transparent URL and do not put the port after the URL useful for google services that wont allow local url?
But i use the 8080 for internal developing where i use the port as a reference for a "dev environment"
I came here looking for a way to specify the height of the select2-enabled dropdown. That what has worked for me:
.select2-container .select2-choice, .select2-result-label {
font-size: 1.5em;
height: 41px;
overflow: auto;
}
.select2-arrow, .select2-chosen {
padding-top: 6px;
}
BEFORE:
AFTER:
You need to understand the different between pass-by-reference and pass-by-value.
Basically, C only support pass-by-value. So you can't reference a variable directly when pass it to a function. If you want to change the variable out a function, which the swap do, you need to use pass-by-reference. To implement pass-by-reference in C, need to use pointer, which can dereference to the value.
The function:
void intSwap(int* a, int* b)
It pass two pointers value to intSwap, and in the function, you swap the values which a/b pointed to, but not the pointer itself. That's why R. Martinho & Dan Fego said it swap two integers, not pointers.
For chars, I think you mean string, are more complicate. String in C is implement as a chars array, which referenced by a char*, a pointer, as the string value. And if you want to pass a char* by pass-by-reference, you need to use the ponter of char*, so you get char**.
Maybe the code below more clearly:
typedef char* str;
void strSwap(str* a, str* b);
The syntax swap(int& a, int& b) is C++, which mean pass-by-reference directly. Maybe some C compiler implement too.
Hope I make it more clearly, not comfuse.
I can't guarantee that this will work for every new iPad Pro which will be released but this works pretty well as of 2019:
@media only screen and (min-width: 1024px) and (max-height: 1366px)
and (-webkit-min-device-pixel-ratio: 1.5) and (hover: none) {
/* ... */
}
Just a quick modification to DaniP's answer, for anyone dealing with elements that can sometimes extend beyond the bounds of the device's viewport.
Added just a slight conditional - In the case of elements that are bigger than the viewport, the element will be revealed once it's top half has completely filled the viewport.
function elementInView(el) {
// The vertical distance between the top of the page and the top of the element.
var elementOffset = $(el).offset().top;
// The height of the element, including padding and borders.
var elementOuterHeight = $(el).outerHeight();
// Height of the window without margins, padding, borders.
var windowHeight = $(window).height();
// The vertical distance between the top of the page and the top of the viewport.
var scrollOffset = $(this).scrollTop();
if (elementOuterHeight < windowHeight) {
// Element is smaller than viewport.
if (scrollOffset > (elementOffset + elementOuterHeight - windowHeight)) {
// Element is completely inside viewport, reveal the element!
return true;
}
} else {
// Element is larger than the viewport, handle visibility differently.
// Consider it visible as soon as it's top half has filled the viewport.
if (scrollOffset > elementOffset) {
// The top of the viewport has touched the top of the element, reveal the element!
return true;
}
}
return false;
}
You have to use a different background image, not color, for each state of the EditText
(focus, enabled, activated).
http://android-holo-colors.com/
In the site above, you can get images from a lot of components in the Holo theme. Just select "EditText" and the color you want. You can see a preview at the bottom of the page.
Download the .zip file, and copy paste the resources in your project (images and the XML).
if your XML is named: apptheme_edit_text_holo_light.xml (or something similar):
Go to your XML "styles.xml" and add the custom EditText
style:
<style name="EditTextCustomHolo" parent="android:Widget.EditText">
<item name="android:background">@drawable/apptheme_edit_text_holo_light</item>
<item name="android:textColor">#ffffff</item>
</style>
Just do this in your EditText
:
<EditText
android:layout_width="wrap_content"
android:layout_height="wrap_content"
style="@style/EditTextCustomHolo"/>
And that's it, I hope it helps you.
The truth value of an empty list is False
whereas for a non-empty list it is True
.
You need to set the property server.contextPath
to /myWebApp
.
Check out this part of the documentation
The easiest way to set that property would be in the properties file you are using (most likely application.properties
) but Spring Boot provides a whole lot of different way to set properties. Check out this part of the documentation
EDIT
As has been mentioned by @AbdullahKhan, as of Spring Boot 2.x the property has been deprecated and should be replaced with server.servlet.contextPath
as has been correctly mentioned in this answer.
Unfortunately for MSForms list box looping through the list items and checking their Selected property is the only way. However, here is an alternative. I am storing/removing the selected item in a variable, you can do this in some remote cell and keep track of it :)
Dim StrSelection As String
Private Sub ListBox1_Change()
If ListBox1.Selected(ListBox1.ListIndex) Then
If StrSelection = "" Then
StrSelection = ListBox1.List(ListBox1.ListIndex)
Else
StrSelection = StrSelection & "," & ListBox1.List(ListBox1.ListIndex)
End If
Else
StrSelection = Replace(StrSelection, "," & ListBox1.List(ListBox1.ListIndex), "")
End If
End Sub
If you'd like to call this method directly on an NSDate object and get the timestamp as a string in milliseconds without any decimal places, define this method as a category:
@implementation NSDate (MyExtensions)
- (NSString *)unixTimestampInMilliseconds
{
return [NSString stringWithFormat:@"%.0f", [self timeIntervalSince1970] * 1000];
}
Using a dict wouldn't like double your memory usage unless the objects you're storing are really tiny, since the values are only pointers to the actual objects:
>>> a = 'foo'
>>> b = [a]
>>> c = [a]
>>> b[0] is c[0]
True
In that example, 'foo' is only stored once. Does that make a difference for you? And exactly how many items are we talking about anyway?
OID's are still in use for Postgres with large objects (though some people would argue large objects are not generally useful anyway). They are also used extensively by system tables. They are used for instance by TOAST which stores larger than 8KB BYTEA's (etc.) off to a separate storage area (transparently) which is used by default by all tables. Their direct use associated with "normal" user tables is basically deprecated.
The oid type is currently implemented as an unsigned four-byte integer. Therefore, it is not large enough to provide database-wide uniqueness in large databases, or even in large individual tables. So, using a user-created table's OID column as a primary key is discouraged. OIDs are best used only for references to system tables.
Apparently the OID sequence "does" wrap if it exceeds 4B 6. So in essence it's a global counter that can wrap. If it does wrap, some slowdown may start occurring when it's used and "searched" for unique values, etc.
See also https://wiki.postgresql.org/wiki/FAQ#What_is_an_OID.3F
You can implement throwing exceptions on mysql query fail on your own. What you need is to write a wrapper for mysql_query function, e.g.:
// user defined. corresponding MySQL errno for duplicate key entry
const MYSQL_DUPLICATE_KEY_ENTRY = 1022;
// user defined MySQL exceptions
class MySQLException extends Exception {}
class MySQLDuplicateKeyException extends MySQLException {}
function my_mysql_query($query, $conn=false) {
$res = mysql_query($query, $conn);
if (!$res) {
$errno = mysql_errno($conn);
$error = mysql_error($conn);
switch ($errno) {
case MYSQL_DUPLICATE_KEY_ENTRY:
throw new MySQLDuplicateKeyException($error, $errno);
break;
default:
throw MySQLException($error, $errno);
break;
}
}
// ...
// doing something
// ...
if ($something_is_wrong) {
throw new Exception("Logic exception while performing query result processing");
}
}
try {
mysql_query("INSERT INTO redirects SET ua_string = '$ua_string'")
}
catch (MySQLDuplicateKeyException $e) {
// duplicate entry exception
$e->getMessage();
}
catch (MySQLException $e) {
// other mysql exception (not duplicate key entry)
$e->getMessage();
}
catch (Exception $e) {
// not a MySQL exception
$e->getMessage();
}
afaik iPhone uses "Helvetica" by default < iOS 10
The UPDATE
statement is given so that older fields can be updated to new value. If your older values are the same as your new ones, why would you need to update it in any case?
For eg. if your columns a
to g
are already set as 2
to 8
; there would be no need to re-update it.
Alternatively, you can use:
INSERT INTO table (id,a,b,c,d,e,f,g)
VALUES (1,2,3,4,5,6,7,8)
ON DUPLICATE KEY
UPDATE a=a, b=b, c=c, d=d, e=e, f=f, g=g;
To get the id
from LAST_INSERT_ID
; you need to specify the backend app you're using for the same.
For LuaSQL, a conn:getlastautoid()
fetches the value.
take advantage of the methods offered by a Series:
>>> import pandas as pd
>>> y = [0, 0, 0, 1, 0, 1, 1, 0, 0, 0, 0, 1]
>>> pd.Series(y).value_counts()
0 8
1 4
dtype: int64
It should also be noted that one key detail about package-lock.json is that it cannot be published, and it will be ignored if found in any place other than the top level package. It shares a format with npm-shrinkwrap.json(5), which is essentially the same file, but allows publication. This is not recommended unless deploying a CLI tool or otherwise using the publication process for producing production packages.
If both package-lock.json and npm-shrinkwrap.json are present in the root of a package, package-lock.json will be completely ignored.
For general purposes of copying any text to the clipboard, I wrote the following function:
function textToClipboard (text) {
var dummy = document.createElement("textarea");
document.body.appendChild(dummy);
dummy.value = text;
dummy.select();
document.execCommand("copy");
document.body.removeChild(dummy);
}
The value of the parameter is inserted into value of a newly created <textarea>
, which is then selected, its value is copied to the clipboard and then it gets removed from the document.
There are different ways to return status code, 1 : RestController class should extends BaseRest class, in BaseRest class we can handle exception and return expected error codes. for example :
@RestController
@RequestMapping
class RestController extends BaseRest{
}
@ControllerAdvice
public class BaseRest {
@ExceptionHandler({Exception.class,...})
@ResponseStatus(value=HttpStatus.INTERNAL_SERVER_ERROR)
public ErrorModel genericError(HttpServletRequest request,
HttpServletResponse response, Exception exception) {
ErrorModel error = new ErrorModel();
resource.addError("error code", exception.getLocalizedMessage());
return error;
}
I have been investigating these ideas and here is my five cents worth. It avoids calling BoundaryNorm
as well as specifying norm
as an argument to scatter
and colorbar
. However I have found no way of eliminating the rather long-winded call to matplotlib.colors.LinearSegmentedColormap.from_list
.
Some background is that matplotlib provides so-called qualitative colormaps, intended to use with discrete data. Set1
, e.g., has 9 easily distinguishable colors, and tab20
could be used for 20 colors. With these maps it could be natural to use their first n colors to color scatter plots with n categories, as the following example does. The example also produces a colorbar with n discrete colors approprately labelled.
import matplotlib, numpy as np, matplotlib.pyplot as plt
n = 5
from_list = matplotlib.colors.LinearSegmentedColormap.from_list
cm = from_list(None, plt.cm.Set1(range(0,n)), n)
x = np.arange(99)
y = x % 11
z = x % n
plt.scatter(x, y, c=z, cmap=cm)
plt.clim(-0.5, n-0.5)
cb = plt.colorbar(ticks=range(0,n), label='Group')
cb.ax.tick_params(length=0)
which produces the image below. The n
in the call to Set1
specifies
the first n
colors of that colormap, and the last n
in the call to from_list
specifies to construct a map with n
colors (the default being 256). In order to set cm
as the default colormap with plt.set_cmap
, I found it to be necessary to give it a name and register it, viz:
cm = from_list('Set15', plt.cm.Set1(range(0,n)), n)
plt.cm.register_cmap(None, cm)
plt.set_cmap(cm)
...
plt.scatter(x, y, c=z)
You can try putting 'Access-Control-Allow-Origin':'*'
in response.writeHead(, {[here]})
.
On my case I solved the problem after 2 hours :
The sender (a tabBar item) wasn't having any Referencing Outlet. So it was pointing nowhere.
Juste create a referencing outlet corresponding to your function.
Hope this could help you guys.
Zxing is an excellent library to perform Qr code scanning and generation. The following implementation uses Zxing library to scan the QR code image Don't forget to add following dependency in the build.gradle
implementation 'me.dm7.barcodescanner:zxing:1.9'
Code scanner activity:
public class QrCodeScanner extends AppCompatActivity implements ZXingScannerView.ResultHandler {
private ZXingScannerView mScannerView;
@Override
public void onCreate(Bundle state) {
super.onCreate(state);
// Programmatically initialize the scanner view
mScannerView = new ZXingScannerView(this);
// Set the scanner view as the content view
setContentView(mScannerView);
}
@Override
public void onResume() {
super.onResume();
// Register ourselves as a handler for scan results.
mScannerView.setResultHandler(this);
// Start camera on resume
mScannerView.startCamera();
}
@Override
public void onPause() {
super.onPause();
// Stop camera on pause
mScannerView.stopCamera();
}
@Override
public void handleResult(Result rawResult) {
// Do something with the result here
// Prints scan results
Logger.verbose("result", rawResult.getText());
// Prints the scan format (qrcode, pdf417 etc.)
Logger.verbose("result", rawResult.getBarcodeFormat().toString());
//If you would like to resume scanning, call this method below:
//mScannerView.resumeCameraPreview(this);
Intent intent = new Intent();
intent.putExtra(AppConstants.KEY_QR_CODE, rawResult.getText());
setResult(RESULT_OK, intent);
finish();
}
}
Make your life easy when working with dates, timestamps and durations. Use HalDateTime from
http://sourceforge.net/projects/haldatetime/?source=directory
For example you can just use it to parse your input like this:
HalDateTime mydate = HalDateTime.valueOf( "25.12.1988" );
System.out.println( mydate ); // will print in ISO format: 1988-12-25
You can also specify patterns for parsing and printing.
As Charles Duffey has stated, XML parsers are best parsed with a proper XML parsing tools. For one time job the following should work.
grep -oPm1 "(?<=<title>)[^<]+"
$ echo "$data"
<item>
<title>15:54:57 - George:</title>
<description>Diane DeConn? You saw Diane DeConn!</description>
</item>
<item>
<title>15:55:17 - Jerry:</title>
<description>Something huh?</description>
$ title=$(grep -oPm1 "(?<=<title>)[^<]+" <<< "$data")
$ echo "$title"
15:54:57 - George:
Position the cursor inside the class, then press ALT + Ins and select Getters and Setters
from the contextual menu.
If you look into CREATE PROCEDURE Syntax for latest MySQL version you'll see that procedure parameter can only contain IN/OUT/INOUT specifier, parameter name and type.
So, default values are still unavailable in latest MySQL version.
The excellent Pandas library adds features to numpy that make these kinds of operations more intuitive IMO. For example:
import numpy as np
import pandas as pd
# column
df = pd.DataFrame([1,2,3])
# row
df2 = pd.DataFrame([[1,2,3]])
You can even define a DataFrame and make a spreadsheet-like pivot table.
What is ultimately a time_t typedef to?
Robust code does not care what the type is.
C species time_t
to be a real type like double, long long, int64_t, int
, etc.
It even could be unsigned
as the return values from many time function indicating error is not -1
, but (time_t)(-1)
- This implementation choice is uncommon.
The point is that the "need-to-know" the type is rare. Code should be written to avoid the need.
Yet a common "need-to-know" occurs when code wants to print the raw time_t
. Casting to the widest integer type will accommodate most modern cases.
time_t now = 0;
time(&now);
printf("%jd", (intmax_t) now);
// or
printf("%lld", (long long) now);
Casting to a double
or long double
will work too, yet could provide inexact decimal output
printf("%.16e", (double) now);
The Python 2 documentation, 7.6. Function definitions gives you a couple of ways to detect whether a caller supplied an optional parameter.
First, you can use special formal parameter syntax *
. If the function definition has a formal parameter preceded by a single *
, then Python populates that parameter with any positional parameters that aren't matched by preceding formal parameters (as a tuple). If the function definition has a formal parameter preceded by **
, then Python populates that parameter with any keyword parameters that aren't matched by preceding formal parameters (as a dict). The function's implementation can check the contents of these parameters for any "optional parameters" of the sort you want.
For instance, here's a function opt_fun
which takes two positional parameters x1
and x2
, and looks for another keyword parameter named "optional".
>>> def opt_fun(x1, x2, *positional_parameters, **keyword_parameters):
... if ('optional' in keyword_parameters):
... print 'optional parameter found, it is ', keyword_parameters['optional']
... else:
... print 'no optional parameter, sorry'
...
>>> opt_fun(1, 2)
no optional parameter, sorry
>>> opt_fun(1,2, optional="yes")
optional parameter found, it is yes
>>> opt_fun(1,2, another="yes")
no optional parameter, sorry
Second, you can supply a default parameter value of some value like None
which a caller would never use. If the parameter has this default value, you know the caller did not specify the parameter. If the parameter has a non-default value, you know it came from the caller.
readChar doesn't have much flexibility so I combined your solutions (readLines and paste).
I have also added a space between each line:
con <- file("/Users/YourtextFile.txt", "r", blocking = FALSE)
singleString <- readLines(con) # empty
singleString <- paste(singleString, sep = " ", collapse = " ")
close(con)
There is a super simple way.
in BaseActivity, Activity or Fragment override attachBaseContext
override fun attachBaseContext(context: Context) {
super.attachBaseContext(context.changeLocale("tr"))
}
extension
fun Context.changeLocale(language:String): Context {
val locale = Locale(language)
Locale.setDefault(locale)
val config = this.resources.configuration
config.setLocale(locale)
return createConfigurationContext(config)
}
The Upload
method's HttpPostedFileBase
parameter must have the same name as the the file input
.
So just change the input to this:
<input type="file" name="file" />
Also, you could find the files in Request.Files
:
[HttpPost]
public ActionResult Upload()
{
if (Request.Files.Count > 0)
{
var file = Request.Files[0];
if (file != null && file.ContentLength > 0)
{
var fileName = Path.GetFileName(file.FileName);
var path = Path.Combine(Server.MapPath("~/Images/"), fileName);
file.SaveAs(path);
}
}
return RedirectToAction("UploadDocument");
}