OpenCV not working properly with python on Linux with anaconda. Getting error that cv2.imshow() is not implemented

1.The easiest way:

conda remove opencv
conda update conda
conda install --channel menpo opencv

or (for OpenCV 3.1) :

conda install -c menpo opencv3

2.And if u don't want to do this, you can try to use matplotlib .

import cv2
import matplotlib.pyplot as plt

img = cv2.imread('img.jpg',0)

plt.imshow(img, cmap='gray')
plt.show()

3.Or try to build library by your own with option WITH_GTK=ON , or smth like that.

Update - 18th Jun 2019

I got this error on my Ubuntu(18.04.1 LTS) system for openCV 3.4.2, as the method call to cv2.imshow was failing. I am using anaconda. Just the below 2 steps helped me resolve:

conda remove opencv
conda install -c conda-forge opencv=4.1.0

If you are using pip, you can try

pip install opencv-contrib-python

I have had to deal with this issue a couple of times, this is what has worked consistently thus far:

conda remove opencv
conda install -c menpo opencv
pip install --upgrade pip
pip install opencv-contrib-python

If you installed OpenCV using the opencv-python pip package at any point in time, be aware of the following note, taken from https://pypi.python.org/pypi/opencv-python

IMPORTANT NOTE MacOS and Linux wheels have currently some limitations:

• video related functionality is not supported (not compiled with FFmpeg)
• for example cv2.imshow() will not work (not compiled with GTK+ 2.x or Carbon support)

Also note that to install from another source, first you must remove the opencv-python package