Tuples, lists, sets, and some notes on exception handling

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'''  Tuples  tuple And list similar , The difference is tuple Can't modify  tulpe Write in parentheses , The elements are separated by commas   The elements of tuples are immutable , But it can contain variable objects , Such as list  Be careful ： Define a 1 An element of tuple, Must be added ,.  You can use subscripts , Slice access , The nature of the visit is the same as list num1 = (1,)# That's the plus , Why  num2 = (2) print(type(num1)) print(type(num2)) # increase ： Connect  tul1 = (1,2,3) tul2 = (3,34,4) tul = tul1 + tul2 print(tul) # Delete ： Deleted the entire tuple variable  del tul #print(tul)# Will report a mistake NameError: name 'tul' is not defined., # check  print(tul1.count(1))# Return the number of occurrences  # Change  #tul1[0] = 2 This will change the report , So it can't be changed  '''
#dict( Dictionaries )
'''  A dictionary is an unordered collection of objects , Use key value storage , With extremely fast search speed .  Keys must be of immutable type   The key must be immutable  '''
# Dictionary definition 
info = {
    "name":" Shangguanhao ","age":19}

# Access to dictionaries 
''' print(info["name"]) print(info["age"]) '''
# Accessed a nonexistent key 
#print(info["gender"]) Direct access will report an error 
''' print(info.get("gender",2 ))# Use get Method , No corresponding key found , Default return ：None print(info.get("age",18))# If you find it , Return value  # increase  info["id"] = "123456" # Delete  #[del] del info["age"] # If you access the deleted key value pair after deletion , Will report a mistake  # It's fine too del info Delete entire dictionary , If you visit the dictionary again, you will report an error  # Sure %s Output brother Zhen dictionary  #print("%s"%info) #[clear] #info.clear() print(info)# The output will not report an error , Output an empty dictionary  # Change  # Just access the change through the key  # check  print(info.keys())# Get all the keys （ list ） print(info.values())# Get all the values （ list ） print(info.items())# Get all the items （ list ）, Each key value is a tuple  # Traverse all the values , Automatic assignment  for key,value in info.items(): print("key=%s,value=%s"%(key,value)) # The same goes for traversing all values  '''
''' # Get the subscript and element content of the list by enumerating  mylist = ["a","b","c","d"] for i,x in enumerate(mylist): print(i,x)  The resulting output  0 a 1 b 2 c 3 d '''
#set( aggregate ) It can be called a collection of dictionary keys , The elements inside are not repeated and disordered , Repeated elements will be times filtered 
s = set([1,1,2,2,3,4,4])
print(s)

'''  list []  Orderly   Variable type   Dictionaries {}  disorder  key immutable  value variable   Tuples ()  Orderly   Immutable type   aggregate {}  disorder   Variable type （ No repetition ） '''

exception handling
try: Inside are local variables
# Code snippets that may report exceptions
except :# Type of exception , If it's one, don't add （）
# If there are two or more （error1,error2） Parentheses required
# If you want to include all exceptions , use exception To replace mistakes
# If you need to print an error and there will be no error report, which will cause the program to stop running
# Can be in error Add after as result
else:
Don't have to else, use finally It means that it will be executed no matter whether an error is reported