1. List
frame
variable = [element 1, element 2, element 3,..... ]
1.1 changing the element
variable[number] = 'element'
Ex.
a = [1,2,3]
a[1] = 4
result a = [1,4,3]
1.2 adding the element
variable.append('element')
1.3 removing the element
variable.remove('element')
1.4 checking the length of the list
len(variable)
Ex.
print(len(variable))
1.5 sorting the list
variable.sort()
Ex.
a.sort()
print(a)
result -> [1,3,4]
2. Tuple -> similar to list but cannot be edited once it is created
Ex.
a = (1,2,3) -> similar to list (a = [1,2,3]) -> but covered by ()
3. Dictionary
frame
variable = {"key" : "value", "key" : "value", "key" : "value",.....}
Ex.
result -> 1
3.1 Adding the dictionary
variable['key'] = value -> just put the key which doesn't exist in the dict data as well as the value
Ex.
result -> {'first': 1, 'second': 2, 'third': 3, 'fourth': 4}
Additionally,
If I put the existing key, the value will be changed.
variable['key(already exist)'] = value(changed)
3.2 Removing dict
del variable['key(already exist)']
3.3 finding key and value
variable.keys() -> will show all the existing keys
variable.values() -> will show all the existing values
4. Set -> represents a set of non-duplicated elements. (must covered by {})
What if there is duplicated data?
Ex.
a = {1,2,3,3,4,5}
print (a)
result -> {1,2,3,4,5}
4.1 adding element
variable.add(element)
4.2 removing element
variable.remove(element)
What if I want to add between two sets?
variable1.union(variable2)
What if I want to get the duplicated data?
variable1.intersection(variable2)
Changing the type of data
1. Explicit Conversion
1.1 int()
1.2 float()
1.3 str()
1.4 bool()
1.5 list(), tuple(), set()
Ex.
a = 6.4343 -> float
b = '5944'
c = int(6)
d = int(b)
result
6
5944
BUT must be aware of the types of data
'3.14'(str type) -> int('3.14') X , float('3.14') O
bool1 = 0
bool2 = ""
bool(bool1)
bool(bool2)
result
False -> 0 is the common data type of false
False -> Empty value, empty list, empty dict, etc(mostly empty data) are considered as false data type
For list(), tuple(), set()
Ex.
a = 1
list(a) -> X
a = [1,2,3,4]
list (a) -> [1,2,3,4]
tuple (a) -> (1,2,3,4)
set (a) -> {1,2,3,4}
str and list can be worked together
result -> ['K', 'E', 'V', 'I', 'N']
So, I can work like this
result -> ['K', 'I', 'V', 'I', 'N']
2. Implicit Conversion -> automatically change the type of data
Ex.
a = 1
b = 1.5
print (a + b)
result -> 2.5
Control statement, loop statement
1. if
frame
if condition:
codes
Ex.
a = 2
if a == 2: -> should use ==, <, >, etc
print(a)
2. else -> used when the condidtion are not satisfied
Ex.
If -> input 40 -> result: bigger than 20
If -> input 15 -> result: whatever
3. elif -> since it is not useful to keep write if, so elif is used when to put mutiple condition
Ex.
If -> input 40 -> result: bigger than 20
If -> input 50 -> result: bigger than 40
If -> input 15 -> result: whatever
Nested Conditions (if:if)
Ex.
If I input 13, then It will show 'nah' but, If I input 5, then it will show 'password'. If I input 10 again, It will show passed or else denied
Tip. -> .lower() -> willt turn the input value into lowercase
Loop statement
1. for -> reiterate based on the collection(list, tuple, string text)
frame
for variable in collection:
codes
2. while -> will continuesly reiterate codes till the condition is satisfited
frame
while condition:
codes
3. break -> stop the codes when certain condition are met
4. continue -> will skip next code and continue the next loop
for i in range(1, 6): -> 1,2,3,4,5
if i % 2 == 0: -> 2,4
continue -> skip
print(i) -> 1,3,5
Tips
range() -> same as like ~
range(1~11) -> will get 1~10(except the last one)
range(number) -> will get 0~number
range(start, stop) -> will get start to start -1
range(start, stop, step) -> will get number base on the stop
ex. (0, 21, 2) -> 2, 4, 6, 8, etc...
enumerate() -> shows the order of the value
ex.
result ->
0 1
1 2
2 3
3 4
4 5
Good night!