## List 
# List basics
    courses = ['History', 'Math', 'Physics', 'CompSci']
    print(courses)
    print(len(courses))
    print(courses[0])
    print(courses[-1]) # start from the end 
    print(courses[4]) # error
    print(courses[0:2]) # the first index include, not the second one
    print(courses[:2]) # from the first to index 2
    print(courses[2:]) # from index 2 to the end

# Add elements to List
    courses1 = ['History', 'Math', 'Physics', 'CompSci']    
    courses1.append('Art')
    print(courses1) # ['History', 'Math', 'Physics', 'CompSci', 'Art']
    
    courses2 = ['History', 'Math', 'Physics', 'CompSci']    
    courses2.insert(0, 'Art')
    print(courses2) # ['Art', 'History', 'Math', 'Physics', 'CompSci']
    
    
    courses3 = ['History', 'Math', 'Physics', 'CompSci'] 
    courses4 = ['Art', 'Education']
    courses3.insert(0, courses4)
    print(courses3) # [['Art', 'Education'], 'History', 'Math', 'Physics', 'CompSci'] 
    
    courses5 = ['History', 'Math', 'Physics', 'CompSci'] 
    courses6 = ['Art', 'Education']
    courses5.extend(courses6)
    print(courses5) # ['History', 'Math', 'Physics', 'CompSci', 'Art', 'Education'] 
    
# Remove elements to List    
    courses = ['History', 'Math', 'Physics', 'CompSci']
    courses.remove('Math')
    print(courses) #['History', 'Physics', 'CompSci']
    
    courses1 = ['History', 'Math', 'Physics', 'CompSci']
    courses.pop()
    print(courses) #['History', 'Math', 'Physics']
    
    
    courses2 = ['History', 'Math', 'Physics', 'CompSci']
    popped = courses.pop()
    print(popped) #'CompSci'
    
# Order in List       
    courses = ['History', 'Math', 'Physics', 'CompSci']
    courses.reverse()
    print(courses) #['CompSci', 'Physics', 'Math', 'History']
    
    courses1 = ['History', 'Math', 'Physics', 'CompSci']
    courses1.sort()
    print(courses1) #['CompSci', 'History', 'Math', 'Physics']
     
    courses2 = ['History', 'Math', 'Physics', 'CompSci']
    courses2.sort(reverse=True)
    print(courses2) #['Physics', 'Math', 'History', 'CompSci']
    
 
    courses3 = ['History', 'Math', 'Physics', 'CompSci']
    courses4 = sorted(courses3)
    print(courses4) #['CompSci', 'History', 'Math', 'Physics']
    
# Min, Max, Sum in List  
    nums = [1,5,2,4,3]
    print(min(nums)) #1
    print(max(nums)) #5
    print(sum(nums)) #15
    
# index in List  
    courses = ['History', 'Math', 'Physics', 'CompSci']
    print(courses.index('ComSci')) # 3
    print(courses.index('Art')) # error
    print('Art' in courses) # False
    print('Math' in courses) # True
    
    for item in courses:
        print(item)  # History Math Physics CompSci
    
    for index, course in enumerate(courses):
        print(index, course)  # 0 History  1 Math  2 Physics  3 CompSci
    
    for index, course in enumerate(courses, start=1):
        print(index, course)  # 1 History  2 Math  3 Physics  4 CompSci
    
# join in List
    courses = ['History', 'Math', 'Physics', 'CompSci']
    course_str = ', '.join(courses)
    new_courses = course_str.split(', ')
    print(course_str) # 'History', 'Math', 'Physics', 'CompSci'
    print(new_courses) # ['History', 'Math', 'Physics', 'CompSci']
    
## Tuple
# List is mutable, Tuple is immnutable, we can't add, append, modify element in Tuple
    list1 = ['History', 'Math', 'Physics', 'CompSci']
    list2 = list1
    print(list1) #['History', 'Math', 'Physics', 'CompSci']
    print(list2) #['History', 'Math', 'Physics', 'CompSci']
    
    list1[0] = 'Art'
    print(list1) #['Art', 'Math', 'Physics', 'CompSci']
    print(list2) #['Art', 'Math', 'Physics', 'CompSci']
    
    tuple1 = ('History', 'Math', 'Physics', 'CompSci')
    tuple2 = tuple1
    print(tuple1) #('History', 'Math', 'Physics', 'CompSci')
    print(tuple2) #('History', 'Math', 'Physics', 'CompSci')
    
    tuple1[0] = 'Art'  # error
    
    
## Set
# Set values are unordered and unduplicated
    set1 = {'History', 'Math', 'Physics', 'CompSci'}
    print(set1) #{'Math', 'History', 'Physics', 'CompSci'} order may change
    
    set2 = {'History', 'Math', 'Physics', 'CompSci', 'Math'}
    print(set2) #{'Math', 'History', 'Physics', 'CompSci'} order may change
    
    set3 = {'History', 'Math', 'Physics', 'CompSci'}
    print('Math' in set3) #True Set is optimized for the check existing
     
    # Set is optimized to find the same and differences between 2 ones
    set4 = {'History', 'Math', 'Physics', 'CompSci'}
    set5 = {'History', 'Math', 'Art', 'Design'}
    print(set4.intersaction(set5)) #{'History', 'Math'}
    print(set4.difference(set5)) #{'Physics', 'CompSci'}
    print(set4.union(set5)) #{'History', 'Math', 'Physics', 'CompSci', 'Art', 'Design'}
    
## How to create empty List, Tuple, Set
    empty_list = []    
    empty_list = list()    
     
    empty_tuple = ()    
    empty_tuple = tuple()    
    
    empty_set = {} # This is wrong, it's a dict
    empty_set = set()

# different types
    num1 = 4
    print(type(num1))
    
    num2 = 2.1
    print(type(num2))
      
# arithmetic operators
    print(5 + 2)
    print(5 - 2)
    print(5 * 2)
    print(5 / 2)
    print(5 // 2) # floor division
    print(3 ** 2) # exponent
    print(3 % 2) # modulus
    print(abs(-3)) # absolute
    print(round(3.6)) # round number 4
    print(round(3.75, 1)) # round number 3.8
    
# calculation order
    print(3 + 2 * 2)
    print((3+2)*2)   
     
# increment
    num1 = 1
    num1 = num1 + 1
    print(num1)
    
    num2 = 1
    num2 += 1
    print(num2)

# comparisons
    print(3 == 2) # equal
    print(3 != 2) # not equal
    print(3 > 2)  # greater than
    print(3 < 2)  # less than
    print(3 >= 2) # greater or equal
    print(3 <= 2) # less or equal

# cast
    num1 = '10'
    num2 = '20'
    print(num1 + num2) # 1020

    num3 = int(num1)
    num4 = int(num2)
    print(num3 + num4) # 30
   

# 1
   message1 = 'Hello World'
   print(message1)

# 2   
   message2 = "hello 'Jimmy'"
   print(message2)
   
# 3   
   message3 = 'Hello World'
   print(len(message3))
   
# 4   
   message4 = 'Hello World'
   print(message4[1])
   print(message4[-1])
   print(message4[0:5]) # first include, second not
   print(message4[:5]) # end to the 5
   print(message4[6:]) # start from the 6
   print(message4[11]) # error

# 5   
   message5 = 'Hello World'
   print(message5.lower())
   print(message5.upper())
   print(message5.count('l')) # count l's number in the message
   print(message5.find('World')) # return 6
   print(message5.find('Unknown')) # return -1

# 6   
   message6 = 'Hello World'
   # or by the same message6 = message6.replace('World', 'You')
   new_message6 = message6.replace('World', 'You')
   print(new_message6)
   
# 7   
   greeting='Hello'
   name='Bob'
   message7 = greeting + ', ' + name
   print(message7)  
   
   message8 = '{}, {}. Welcome!'.format(greeting, name)
   print(message8)
   
   message9 = f'{greeting}, {name}. Welcome!' # python >3.10
   print(message9)
   
   message10 = f'{greeting}, {name.upper()}. Welcome!' # python >3.10
   print(message10)
   
# 8
   print(help(str))   
   print(help(str.lower))