Python: a quick overview

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sudo apt update && sudo apt upgrade

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sudo apt install python2

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sudo apt install python3

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# Here some examples
myIntVariable = 435                             # Normal integer variable
myFloatVariable = 34.465                        # Normal float variable
myStringVariable = "I am a string!"             # String variable - you don't have to set length nor mem alloc
myBoolVariable = False                          # Boolean variable
myListVariable = [3, 4, 5, 14232]               # List of integer values
myComplexListVariable = [3, 2.546654, "String"] # Mixed list! This feature is great!

# Also reassignment is dynamic
myIntVariable = "Now I'm a string!"
myComplexListVariable = [ ['c', 3454] , [43.54, "Another string"] , [22, True] ]
myStringVariable = ()

# Complex numbers
myComplexNumber = 0+1j                          # Yes, Python can manage complex numbers too!

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myVarA = 55
myVarB = 71
myVarP = 3.14

def myFunctionA():
    localVarQ = "PI is: "
    print(localVarQ+str(myVarP))      # myVarP is accessed as a read-only variable so it is linked to the outer one

def myFunctionA2():
    myVarP = 3.141592                 # MyVarP is accessed in writing mode so myVarP in myFunctionA2 is NOT the 
    localVarQ = "PI is: "             # same myVarP of the outer scope
    print(localVarQ+str(myVarP))

def myFunctionA3():
    global myVarP                     # The 'global' keyword makes the function understand that myVarP inside the  
    myVarP = 3.14159265358            # myFunctionA3 scope is the same as the outer one! Here the OUTER variable is accessed and modified
    localVarQ = "PI is: "
    print(localVarQ+str(myVarP))
    
def myFunctionB(myVarA, myVarB):
    print(str(myVarA*myVarB))         # This two variables are local and not related to the outer ones

class myClass:
    myVarA = 42                       # These two variables are locally defined
    myVarB = 2.71828182
    def printOuterValues(self):       # Variables without 'self.' are the outer ones
        print("Outer Values: ",myVarA,myVarB)
    def printInnerValues(self):       # Variables with 'self.' are the inner ones
        print("Inner values ",self.myVarA,self.myVarB)
    
print(myVarA,myVarB,myVarP)
myFunctionA()
print(myVarA,myVarB,myVarP)
myFunctionA2()
print(myVarA,myVarB,myVarP)
myFunctionA3()
print(myVarA,myVarB,myVarP)
myFunctionB(54,70)
print(myVarA,myVarB,myVarP)
myObj = myClass()
myObj.printOuterValues()
myObj.printInnerValues()
print(myVarA,myVarB,myVarP)
myObj.myVarA = 105
myObj.myVarB = 1
myObj.printOuterValues()
myObj.printInnerValues()
print(myVarA,myVarB,myVarP)
    

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# Here I define two functions and I recall one of them in the main script when I need it

# This function returns the area of a trapezium
def trapzAreaFunction(bmin,bmaj,step):
    return (float(bmin)+float(bmaj))*float(step)/2.0

# This function returns the integral of a y=f(x), given y and x as two lists
# It is based on the previous function for the single trapezium area calculation
def integralCalcFunction(y,x):
    intsum = 0
    # Check if the two lists have the same length
    if len(x) != len (y):
        return 0
    l = len(y)              # len is a built-in Python function to know the number of elements in a list 
    for i in range(0,l-1):  # range is a built-in Python function that returns a list of numbers
        intsum += trapzAreaFunction(y[i],y[i+1],x[i+1]-x[i])
    return intsum

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def functionA(x,y):     # This functionA...
	return x+y
	
def functionB(k,l):
	def functionA(x,y):     # and this one are not the same; the latter is local to functionB only
		return x+y-y**2
	return functionA(k,l)
	
print (functionA(45,11), functionB(45,11))

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import math             # If you want to refer to 'math' library functions as math.<funct name>
from math import *      # If you want to use directly <funct name> along your code
import math as m        # If you want to address the library with the name you prefer (alias)

# Example of first import mode
freq = 1000
timeInst = 0.4
x = math.sin(2*math.pi*freq*timeInst) # pi is a constant and sin is a function, both defined in 'math' library

# Example of second import mode
freq = 1000
timeInst = 0.4
x = sin(2*pi*freq*timeInst) # pi is a constant and sin is a function, both defined in 'math' library

# Example of third import mode
freq = 1000
timeInst = 0.4
x = m.sin(2*m.pi*freq*timeInst) # Here 'm.' was used instead of 'math.' since the library was imported with an alias

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# Python 2.7 code

highestPrime = 0
for i in range(2,100001):
	flag = 0
	for j in range(2,i):
		if (i%j == 0):
			flag = 1
			break
	if (flag == 1):
		continue
	else:
		highestPrime = i
print highestPrime

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// C code

#include <stdio.h>

int main(){
	int highestPrime = 0;
	int flag = 0;
	for(int i=2; i<100001; i++){
		flag = 0;
		for(int j=2; j<i; j++){
			if(i%j == 0){
				flag = 1;
				break;
			}
		}
		if(flag == 1){
			continue;
		}
		else{
			highestPrime = i;
		}
	}
	printf("%d\n",highestPrime);
	return 0;
}