### Nudge Notes - Python Language Basics

1. Datatypes in Python:

• None
• Numeric
• float -> 1.5
• int -> 5
• complex -> 2+5j
• bool -> True/false
• Sequence
• List -> [3,5,6,7,1]
• Tuple -> (3,5,6,7,1)
• Set -> {3,5,6,7,1}
• String -> "Akshay"
• Range
• range(5) -> range(0, 5)
• list(range(5)) -> [0,1,2,3,4]
• list(range(2,10,2)) -> [2,4,6,8]
• Dictonary
• product_price = {'book': 50, 'pen': 300, 'eraser': 10}
• product_price.get('book') -> 50
2. Number Conversion in Python
• bin(28) -> 0b11100
• oct(28) -> 0o34
• hex(28) ->  0x1c
3. Swap two numbers in Python
a = 5
b = 6
• Method #1:
a, b = b, a
• Method #2
a = a + b
b = a - b
a = a - b
4. "math" module in python

import math
• math.sqrt(25) -> 5.0
• math.floor(2.5) -> 2.0
• math.ceil(2.5) -> 3.0
• math.pow(2, 3) -> 8.0
• math.pi -> 3.141592653589793
• math.e -> 2.718281828459045
5. How to import a module in python
• import math
• import math as m
• from math import sqrt, pow
6. How to take input from command line in python

from sys import argv

x = int(argv)
y = int(argv)
z = x + y
print(z)

7. Print below pattern in Python

str1 = "ABCD"
str2 = "PQR"
for i in range(4):
print(str1[:i+1]+str2[i:])

8. Use else with for loop in python
• for loop must have 'break' statement in it to use the 'else'.
• example: find the number in the list that is divisible by 2
digits = [7, 3, 5, 11]
for digit in digits:
if digit%2==0:
print(digit)
break;
else:

9. Array in python
• Array is similar to list but must have elements of same datatype.
from array import *
# 'i' denotes the type of array i.e. integer
digits = array('i', [1,2,4,5,7])

# u denotes the unicode type array
unico = array('u', ["a","k","s","h","a","y"])

#copying array
digitcp = array(digits.typecode, [ a for a in digits])

#print array with for loop
for d in unico:
print(d)

* These notes only meant to remind the basics of Python. These are not full notes.

### How to kill a process running on particular port in Linux

If port 8080 needs to be kill use below single command: kill -9 \$(lsof -t -i:8080) Note: remove -9 from the command, if you don't want to kill the process violently. To list any process listening to the port 8080: lsof -i:8080 Use any port number that you want to kill.