Operations:
Output: Sample prints
print(5 + 5) #Addition
print(5 - 5) # subtraction
print(3 * 5) # Multiplication
print(10 / 2) #Division
print(18 % 7) #Modulo
print(4 ** 2) #exponentiation
# How much is your INR 100 worth
after 7 years at the rate of interest per year is 10%?
print(100 * 1.1 ** 7)
Variables:
Str - “sangeeth”, ‘gowtham’
Bool - True /False
Int – 1, 9
Float – 1.98, 8.78
Function: Type()
- //to find unknown type of variables
List:
My_list = []
Ex:
= [1, 3, 4, 2]
= [[1, 2, 3], [4, 5, 7]]
= [1 + 2, "a" * 5, 3] =
[3,aaa,3]
= ["room1", 11.2478,
"room2", 8.459, "room3", 74.56, "room4", 74.698,
"room5", 10.25]
Subset listing:
List Index get: [0,1,2,3…]
(Asc), [….-3,-2,-1] [Desc]
List Slicing: [Start
(inclusive) : End (exclusive)]
My_list = ["room1", 11.2478,
"room2", 8.459, "room3", 74.56, "room4", 74.698,
"room5", 10.25]
Get_First_6list = My_list [:6] or
Get_First_6list = My_list [1:6] or Get_last_list = My_list[6:]
Sub setting lists of lists:
My_list =
[["a", "b", "c"], ["d", "e",
"f"], ["g", "h", "i"]]
My_list[2][0]
My_list[2][:2]
List Manipulation:
My_list =
["room1", 11.2478, "room2", 8.459, "room3",
74.56, "room4", 74.698, "room5", 10.25]
To update list
My_list[<index
position>] = “room5” or 9.897
Adding to new list by amending
My_list_1 = My_list
+ [“room6”, 24.5896]
Delete list
del(My_list [10]); del(My_list [11])
del(My_list [10:11])
del(My_list [-4:-2])
del(My_list [-3]); del(My_list [-4])
Assigning one list to another
My_list
_Copy = My_list (Note: while update
My_list_copy it will affect My_list)
My_list_copy1 = My_list [:] (Note: This will copy all list values
from My_list, but while update My_list_copy1 it will affect My_list)
Functions:
Max
Min
Sorted
len
Complex
Help(<functionName>) – to get
details for function and arguments
Methods:
Upper (Ex:
<StrVariables>.upper()), Count (Ex: <Variables>.count(..))
print(<list>.index(20.0)) –
Index position finding
print(<list>.count(9.50)) –
getting count of repeated times in list values
append(), that adds an element to
the list it is called on,
remove(), that removes the first
element of a list that matches the input, and
reverse(), that reverses the order
of the elements in the list it is called on.
Packages:
import math
import numpy
from math import radians (Note: To import radians function from
math package)
from scipy.linalg import inv as
my_inv (Note: Suppose you want to
use the function inv(), which is in the linalg subpackage of the scipy package)
Numpy: (Numeric
Python)
Adv:
Powerful
Collection of values
Hold different types
Change add remove
Data Science
Mathematical
operation over collection
Speed
NumPy array:
Calculation
over entire arrays
Easy
and fast for complex calculation
Syntax: Example
import numpy as np
np_array1 =
np.array(array1)
Manipulation with
np array = np_array1 + np_array2 (+, _ ,*, /, **)
Ex:
height = [180,
175, 165, 168, 189, 195]
weight = [74, 52,
42, 85, 96, 53]
import numpy as np
np_height =
np.array(height)
print(np_height)
np_height_m =
np_height * 0.0254
print(np_height_m)
np_height_m = np.array(height)
* 0.0254
np_weight_kg =
np.array(weight) * 0.453592
bmi = np_weight_kg
/ np_height_m ** 2
print(bmi[light])
2D – NumPy Array
N dimensional array
My_list = [[180, 78.4],
[215, 102.7],
[210, 98.5],
[188, 75.2]]
import numpy as np
np_ My_list = np.array(My_list)
print(type(np_My_list))
print(np_My_list.shape)
Output:
<class 'numpy.ndarray'>
(4, 2) (Shape will return total
size of array (row, column))
Ex:
# Print out the 4th row of np_My_list
print(np_My_list [4,:])
# Select the entire second column
of np_My_list
np_array1 np_My_list [:,1]
# Print out value of 3th player
print(np_baseball[2, 0])
Output:
[ 70 195]
75
Basic statistics:
Data Analysis: