Useful command

1. compile cpp file that includes opencv library path using g++

$ g++ test.cpp -o test `pkg-config --cflags --libs opencv`

2. build cpp file using bazel

~tensorflow) $ bazel build tensorflow/project/...

3. remove folder command (ubuntu)

$ sudo rm -r foldername

4. data type change python

a = np.zeros(10) # float

a_ = a.astype('int8') # int8

5. python sqrt function

import math

a = math.sqrt(4)

print(a)

-> 2

6. python exp function

import math

a = math.exp(4)

7. #define function

#define MIN(X,Y) (X < Y) > X : Y

#define MAX(X,Y) (X > Y) > X : Y

8. python numpy array size

a = np.empty(10,12)

b = a.shape()

print(b(0)) -> 10

9. binary2decimal - decimal2binary in python

a = bin(4)[2:] # string type
print(a) # 100 is printed
b = int(a, 2)
print(b) # 4 is printed

10. binary2decimal - decimal2binary with fixed length in python

a = bin(4)[2:].zfill(5) # {str} '00100'
b = int(a,2)
print(b) # 4

11. check file exist in python

os.path.isfile(path_to_file)

12. my D drive address (ubuntu)

/media/dooseop/64D4183AD41810C2/

13. image flip left right (python)

image_out = np.fliplr(image_in)

14. random number generator

np.random.rand(1) # from 0 to 1

15. number 2 string in python

b = 1.25

c = str(b)

16. get_variable setting for trainable or untrainable

tf.get_variable("a", a, trainable=False)

tf.get_variable("a", a, trainable=True)

17. kill process in ubuntu

$ ps -ef

$ kill -9 pid_number

18. copy files in python

from shutil import copyfile

copyfile(src, dst)

19. rename folder or directory (ubuntu)

mv /home/user/oldname /home/user/newname

20. check existance of file

for i in range(0, len(filenames)):
    if (os.path.isfile(filenames[i]) == False):
        print('following file does not exist : ' + filenames[i])