ERROR: Could not build wheels for cryptography which use PEP 517 and cannot be installed directly
Setting cryptography to version 2.8 in requirements.txt fixed the issue.
python
How do I access my webcam in Python?
OpenCV has support for getting data from a webcam, and it comes with Python wrappers by default, you also need to install numpy for the OpenCV Python extension (called cv2) to work. As of 2019, you can install both of these libraries with pip: pip install numpy pip install opencv-python More information on using OpenCV with Python. An example copied … Read more
Remove specific characters from a string in Python
Strings in Python are immutable (can’t be changed). Because of this, the effect of line.replace(…) is just to create a new string, rather than changing the old one. You need to rebind (assign) it to line in order to have that variable take the new value, with those characters removed. Also, the way you are doing it is going to be kind of … Read more
Python: What OS am I running on?
The output of platform.system() is as follows: Linux: Linux Mac: Darwin Windows: Windows See: platform — Access to underlying platform’s identifying data
What is a unicode string?
Update: Python 3 In Python 3, Unicode strings are the default. The type str is a collection of Unicode code points, and the type bytes is used for representing collections of 8-bit integers (often interpreted as ASCII characters). Here is the code from the question, updated for Python 3: Working with files: Historical answer: Python 2 In Python 2, … Read more
What is the difference between ‘SAME’ and ‘VALID’ padding in tf.nn.max_pool of tensorflow?
I’ll give an example to make it clearer: x: input image of shape [2, 3], 1 channel valid_pad: max pool with 2×2 kernel, stride 2 and VALID padding. same_pad: max pool with 2×2 kernel, stride 2 and SAME padding (this is the classic way to go) The output shapes are: valid_pad: here, no padding so the output … Read more
What is the difference between random.randint and randrange?
The docs on randrange say: random.randrange([start], stop[, step]) Return a randomly selected element from range(start, stop, step). This is equivalent to choice(range(start, stop, step)), but doesn’t actually build a range object. And range(start, stop) returns [start, start+step, …, stop-1], not [start, start+step, …, stop]. As for why… zero-based counting rules and range(n) should return n elements, I suppose. Most useful for getting a random index, I suppose. While randint is documented … Read more
What does ‘wb’ mean in this code, using Python?
File mode, write and binary. Since you are writing a .jpg file, it looks fine. But if you supposed to read that jpg file you need to use ‘rb’ More info On Windows, ‘b’ appended to the mode opens the file in binary mode, so there are also modes like ‘rb’, ‘wb’, and ‘r+b’. Python on … Read more
How do I merge lists in python? [duplicate]
+ operator can be used to merge two lists. Lists can be merged like this in python. Building on the same idea, if you want to join multiple lists or a list of lists to a single list, you can still use “+” but inside a reduce method like this,
threshold in 2D numpy array
One solution: The first part array < 25 gives you an array of the same shape that is 1 (True) where values are less than 25 and 0 (False) otherwise. Element-wise multiplication with the original array retains the values that are smaller than 25 and sets the rest to 0. This does not change the … Read more