[ ] = List
{ } = Dictionary
( ) = Tuple
Boolean:- boolean_true_of_false
Identified by square brackets and uses comma as seperator between elements. A list element is looked up by it's position in the list.
list = ['value1', 'value2']
Remember, list indices start at 0!!
To get the first item, start with the index 0:-
firstitem = list[0]
Add a new item to the end of the list with:-
list.append(value3)
Add a new item in the middle:-
list.insert(value2)
Select the last item in a list, this example splits a file url on directory separator (/), and selects the last item which should be the filename. Won't work on windows, but who cares!!
fileName = key.split('/')[-1]
Iterate over a list
# for loop for index in list: print(index)
Identified by curly brackets and uses “:” to seperate out a Key and a Value. A value in a dictionary is referenced by it's key, the actual order of items stored in a dictionary can change, so you cannot retreive a value based on the position if you just print out the whole dictionary, you have to use the key.
dict = { "key1": "value1", "key2": "value2" }
If you want to look up the meaning of a word in English, you use a Dictionary to find the word (Key) and then read out the meaning of the word (Value).
wordlist = { 'obfuscate': 'to make something less clear and harder to understand, especially intentionally', 'clarify': 'to make something clear or easier to understand by giving more details' }
So:-
definition = wordlist['obfuscate']
returns to make something less clear and harder to understand, especially intentionally
As a dictionary is referenced by it's key to get a value, adding a new element is as easy as just creating a new key:value pair, there is no concept of insert as with a list.
wordlist.update({'understand':'to know the meaning of something that someone says'}) wordlist['difficult'] = 'needing skill or effort'
Testing if a key exists in a dictionary, key in dictionary evaluates to true or false:-
if record["Key1"] in record: record["Key2"] = record["Key1"]
Print just keys:-
print(dictionary.keys())
Print all keys and values in a dictionary:-
for key in dict: print(key, dict[key])
Print out each key/value line by line:-
for key, value in get_metadata_response.items(): print(key, ' : ', value)
Testing keys, check if a dictionary contains a specified key:-
if 'user_a' in metadata.keys(): print("user_a supplied") elif 'user_b' in metadata.keys(): print("user_b supplied") else: print('Neither user A or B')
A tuples is an immutable sequence. This means you cannot change it after it is created.
tuple = (a, b, c)
In Python a string is a list so you can address individual elements in it using list notation.
So to select a portion of a string you can address each character as a list element:-
account = '445156287145' removechar = 8 result1 = account[removechar:] result2 = account[removechar:len(account)] print(result1, result2)
7145 7145
listOfDict = [ {'foo':1,'bar':123}, {'boo':3,'mar':234}, {'moo':5,'par':345} ]
Booleans are either “True or False”
# Add user to user_model table, sql code to add new row OR update existing one:-
# https://stackoverflow.com/questions/15383852/sql-if-exists-update-else-insert-into
user_model_sql = f'''
insert into user_model(highside_user_id, login_status)
values ('{hsusername}', true)
on duplicate key
update highside_user_id = values(highside_user_id), login_status = values(login_status);
'''
mysql_query = f“SELECT IF(login_status, 'true', 'false') from user_model WHERE highside_user_id = '{sessionname}'; ”