Interesting Stuff Using Python Part 1

Let us discuss some cool tips and tricks that can be done using Python.

Khushwant Soni
30 January 2018 | Khushwant Soni
   

In this article, we’re going to do some interesting and fun stuff using python and its built-in Functions that you probably didn’t know about.

Building a Calculator in Python

Things You Already Need To Know:

In this program, we will be building a powerful calculator in which you can give input with any number of operations in the form of any mathematical expression. And we will be also performing calculations on the answers of every step as we do in a real calculator.

You should know about the precedence order of the operations to solve complex expressions, If you don’t know, please refer to the table below (priority From high to low).

Operation Symbol
Parentheses ()
Exponentiation **
Multiplication *
Division /
Addition +
Subtraction -

Now let’s come to the practical part. Python has a built-in function which you may haven’t used yet, eval(). Eval function takes a string of mathematical expression as input and generates output. Make sure to pass a valid mathematical expression which you want to solve.

You can even pass a string with 500-1000 operands.

Here’s the code of calculator below:

print("Enter any expression you want to solve.")
total =''
while True:
    ex=input(total)
    total = str(eval(total+ex))
    print("answer:",total)
     choice = input('Do You wish to continue calculating? (Y/N) ')
    if (choice == 'n') or (choice == 'N'):
        break
    else:
        continue

Output:

Enter any expression you want to solve.
3+6-225**3*5-23//6
answer: -56953119
Do You wish to continue calculating? (Y/N) Y
-56953119+89**5+7*2
answer: 5527106344
Do You wish to continue calculating? (Y/N) Y
5527106344-7**12-8*9
answer: -8314180929
Do You wish to continue calculating? (Y/N) Y     
-8314180929+6**17+9-4//2
answer: 16918345263814
Do You wish to continue calculating? (Y/N) N

Membership Operator ‘in’

Things You Already Need To Know:

Most of the beginners use this membership operator (in) only in for loops, But we can also use it directly on data structures like string, list, set, tuple & dictionary. Just write the element and use ‘in’ along with the data structure you want to check into. It will give output in boolean form, Either True or False.

Example 1:

mystring='principle'
print('p' in mystring)

Output:

True

Example 2:

mylist=['p' , 'i' , 'n' , 'e' , 'a' , 'p' , 'p' , 'l' , 'e']
print('i' in mylist)

Output:

True

Example 3:

myset={ 'p' , 'y' , 't' , 'h' , 'o' , 'n' }
print('k' in myset)

Output:

False

Example 4:

mytuple=('p','i','n','e','a','p','p','l','e')
print('l' in mytuple)

Output:

True

Example 5:

mydict={'d':3, 'i':2 , 'n':4, 'e':6, 'a':1, 'p':5, 'l':8}
print('b' in mydict)

Output:

False

Checking Inequalities

Things You Already Need To Know:

You can check for any inequality in python quite easily. Just write the inequality you want to check and print it. This thing is much useful for large calculations and exponents. The output will be in boolean form, either True or False
Below are the examples containing some of the cases of inequalities.

Example 1:
Consider a very basic inequality with 2 operands

var=3
print(1<var)

Output:

True

Example 2:
Now we’ll be having 3 operands

var=97
print(17<=var<=20)

Output:

False

Example 3:
Now it’s time for some exponents.

var=113
print(2**4<var<=8**9)

Output:

True

Example 4:
Now let’s make a complex inequality

var1=87
var2=8**2
var3=15387**5
var4=52*6
print(var3>=var4>=var1>=var2)

Output:

True

Interactive ‘_’ Operator

Things You Already Need To Know:

Many of you may haven’t heard of this before. We can check the value of last command executed in interactive command line mode using underscore(’ _ ‘) operator.

Example:

>>>"hello"
hello
>>>_
hello

This is only used in the interactive command line of python.

Printing all the List elements along with their indexes

Things You Already Need To Know:

At some point of time, you may need to know all the elements present in a list along with their indexes. This code below will get your work done.

a=["Apple", "Banana", "Pineapple", "Mango", "Watermelon"]
for i in range(len(a)):
    print(a[i],":",i)

Output:

Apple : 0
Banana : 1
Pineapple : 2
Mango : 3
Watermelon : 4




       
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