Foundation
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# variable declaration
# ============================
some_variable = None;
some_variable = 5;
x,y,z = 10,20,30; # x=10; y=20; z=30
# data types
type(10); # int
type(10.55); # float
type('Hello World'); # str
type(False); # bool
type([]); # list
type(None); # NoneType
# data type conversion
# ============================
str(10); # int to str
int('100'); # str to int
float(10) # int to float
float('100'); # str to float
bool(1); # int to bool
bool('True'); # str to bool
# string data type operations
# ============================
'*' * 10; # **********
'ali'.upper(); # ALI
'ali'.capitalize(); # Ali
'ALI'.lower(); # ali
'to be or not to be'.replace('be', 'do'); # to do or not to do
len('ali'); # 3
','.join(['a','b']); # a,b
name = 'Ali'
print(f'Name: {name}'); # Name: Ali
# number data type (int, float) operations
# ========================================
2 ** 3; # 8
5 / 4; # 1.25
5 // 4; # 1 (rounded down to int)
6 % 4; # 2 (remainder)
abs(-3.4); # 3.4 (positive)
bin(5); # 0b101 (Binary representation... 101)
round(3.5); # 4
# List data type operations
# ============================
some_list = [0,1,2,3,4,5,6,7,8,9];
len(some_list); # 10
# [start:stop:stepover]
some_list[0]; # 0
some_list[:]; # 0123456789
some_list[0:]; # 0123456789
some_list[0:8]; # 01234567
some_list[2:5]; # 234
some_list[:4]; # 0123
some_list[0:8:2]; # 024
some_list[::2]; # 0246
some_list[-1]; # 9
some_list[::-1]; # 9876543210
some_list[0] = -1; # list are mutable
# Note: string is also a list of characters i.e. '0123456789'[0] => 0
# strings are imutable i.e. '0123456789'[0] = -1 will throw error
some_list_copy = some_list[:]; # list copy or clone
some_list_copy2 = some_list.copy(); # list copy or clone
grades = ['A','B'];
grades.append('C'); # ['A','B','C']
grades.insert(1,'A+') # ['A','A+',B','C']
grades.extend(['D','F']); # ['A','A+',B','C','D','F']
grades.pop(); # ['A','A+',B','C','D']
grades.pop(1); # ['A',B','C','D']
grades.remove('B'); # ['A', 'C', 'D']
grades.index('A'); # 0
'A' in grades; # True
grades.append('A'); # ['A', 'C', 'D', 'A']
grades.count('A'); # 2 i.e. A comes 2 times
['X', 'Z', 'Y'].sort(); # ['X','Y','Z'] modifies the original list
sorted(['X', 'Z', 'Y']); # ['X','Y','Z'] returns a new sorted list
['X', 'Z', 'Y'].reverse(); # ['Y','Z','X']
['X', 'Z', 'Y'][::-1]; # ['Y','Z','X']
grades.clear(); # []
marks = list(range(1, 5)); # [1,2,3,4,5]
marks = list(range(5)); # [0,1,2,3,4]
# Lists usage as Matrix
# =======================
matrix = [[1,2,3],[4,5,6],[7,8,9]]
print(matrix[0][0] + matrix[1][1] + matrix[2][2]); # 1+5+9 => 15
# List unpacking
a,b,c,*other, d = [1,2,3,4,5,6,7]; # a=1; b=2; c=3; other=[4, 5, 6]; d=7
Python
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