#!/usr/bin/env python
# coding: utf-8

# # Installation
# 
# - python enviroment
#  - anaconda
#  - linux/virtualenv
#    - [WSL on windows](https://ubuntu.com/wsl)
#    - virtualenv --system-site-packages p3
# - jupyter
#  - pip install jupyter

# # Linux terminal essential

# ```
# cd ..                                                       
# cd # back to home dir                                       
# cd ~/p2 # ~ means home dir as well                             
# 
# ls # dir
# ```
# 
# \# install vim: sudo is to notify running as administrater,                         
# \# apt-get install to install package,                     
# \# vim is a common editor (extension of vi)                 
# ```
# sudo apt-get install vim 
# sudo apt-cache search vim # search packages relating to vi
# ```
# 
# ```
# gedit tmp.py # open to edit a file                        
# ctrl-z # break the current job                                   
# bg # send job to background                                              
# fg # send job back to foreground                                      
# ctrl-c # kill foreground job                                           
# ps aux | grep gedit # list all jobs and then search for "gedit" jobs              
# kill -9 12345 # kill job with job number 12345                                        
# ```
# 
# \# extract the audio channel of dummy.mp4                                     
# \# audio format suppose to be aac though                                     
# \# change extension (.ac3/.flac) accordingly                                       
# ```
# ffmpeg -i dummy.mp4 -acodec copy -vn audio.aac                   
# ```
# 
# #extract audio channels from all mp4 files in current folder    
# ```
# ls -1 \*.mp4|sed 's/\(.*\)\.mp4/ffmpeg -i "&" -acodec copy -vn "\1.aac"/'|sh
# ```
# 

# # Setup virtualenv (tested on Ubuntu 18.04) 

# ```
# sudo apt-get install python-virtualenv
# virtualenv ~/p2 # create a virtualenv with python2
# virtualenv --python=/usr/bin/python3 ~/p3 # create a virtualenv with python3
# source ~/p2/bin/activate
# ```
# For windows
# 
# ```
# conda create -n p36 python=3.6 # dlib seems to be faster than in 3.77
# conda activate p36
# ```

# # help

# In[99]:


help('if')


# In[6]:


import numpy


# In[1]:


# help(numpy)


# In[2]:


# help(numpy.sort)


# In[7]:


get_ipython().run_line_magic('pinfo', 'numpy.sort')


# In[106]:


dir(numpy)


# In[107]:


dir(numpy.sort)


# In[110]:


import inspect

inspect.getmembers(numpy.sort)


# In[111]:


help(inspect.getmembers)


# In[112]:


inspect.getsourcefile(numpy.sort)


# In[114]:


print(inspect.getsource(numpy.sort))


# # arithmetics

# In[6]:


2**3


# In[5]:


1+1


# In[ ]:


#a,b ctrl-_


# In[9]:


import math
math.cos(90)


# In[10]:


import numpy as np
np.cos(90)


# # if elif else

# In[11]:


#if

if 1>0:
    print('1>0')
else:
    print('error')


# In[14]:


x=[1,2]

bigger=x[0] if x[0]>x[1] else x[1]
print(bigger)


# In[18]:


state='oklahoma'

if state.lower()=='oklahoma':
    abr='ok'
elif state.lower()=='texas':
    abr='tx'
elif state.lower()=='hawaii':
    abr='hi'
print(abr)


# # for loop

# In[15]:


alist=[1,2,3]
#for

for l in alist:
    print(l)


# In[20]:


for i in range(10):
    print(i)


# ## shorthand

# In[39]:


odd_numbers2=[c*2+1 for c in range(10)]
print(odd_numbers2)


# In[37]:


odd_numbers=[c for c in range(10) if c%2==1]
print(odd_numbers)


# ## enumerate

# In[1]:


states=['texas','oklahoma','hawaii']
for state in states:
    print(state)
    
for i,state in enumerate(states):
    print(str(i)+': '+state)


# ## zip

# In[2]:


for i,state in zip(range(3),states):
    print(str(i)+': '+state)


# ## = does not create copy 

# In[3]:


states_copy = states
states_copy.append('kansas')
print(states)


# In[4]:


states_copy = states.copy()                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               
states_copy.append('tenesse')
print(states_copy)
print(states)


# In[5]:


''.join([c*3 for c in 'computer vision'])


# ## append and pop
# 
# 

# In[6]:


print(states)


# In[7]:


states.pop(1)


# In[8]:


print(states)


# In[9]:


states.insert(1,'oklahoma')
print(states)


# In[10]:


states.remove('hawaii')
print(states)


# In[11]:


odd_numbers = [i for i in range(20)]
for i in odd_numbers:
    if i%2==0:
        odd_numbers.remove(i)
print(odd_numbers)


# # dict

# In[12]:


states=dict()


# In[13]:


states


# In[14]:


states={'ok':'oklahoma','tx':'texas','hi':'hawaii'}


# In[15]:


for key in states:
    print(key)


# In[16]:


states.keys()


# In[17]:


states.values()


# In[18]:


abrvs=['ok','tx','hi']
states=['oklahoma','texas','hawaii']

state_map=dict([(abrv,state) for abrv,state in zip(abrvs,states)])


# In[19]:


print(state_map)


# In[20]:


state_map.pop('tx')


# In[21]:


state_map


# ## find key by value

# In[22]:


list(state_map.keys())[list(state_map.values()).index('hawaii')]


# # Fun

# In[23]:


from datetime import date, timedelta


# In[24]:


date.today()


# In[25]:


date(2022,1,16)+timedelta(weeks=1)


# # numpy

# In[27]:


import numpy as np
np.array([1,2,3,4])


# In[28]:


np.array(range(16)).reshape((4,4))


# In[29]:


np.ones(4)


# In[30]:


np.linalg.eig(np.random.randn(4,4))


# In[31]:


np.linalg.svd(np.random.randn(4,5))


# In[32]:


all_one=np.ones((3,3))
np.zeros_like(all_one)


# In[33]:


x=np.ones((1,3))
x @ all_one @ x.T


# # IO

# In[34]:


with open('opencv basic.ipynb') as fpt:
    print(fpt.read())


# In[35]:


import pickle 

a={'hello':'world'}

with open('dummy.pickle','wb') as fpt:
    pickle.dump(a,fpt)
    
with open('dummy.pickle','rb') as fpt:
    b = pickle.load(fpt)
    
b    


# In[36]:


from scipy.io import savemat,loadmat # save and load matlab mat files

x=range(10)
mdic={'x':x}
savemat('dummy.mat',mdic)


# In[37]:


mdic2=loadmat('dummy.mat')

mdic2


# # plotting

# In[38]:


from matplotlib import pyplot as plt
get_ipython().run_line_magic('matplotlib', 'inline')

plt.figure(figsize=(10,10))
plt.plot(range(10))
plt.xlabel('dummy')
plt.title('hello')