Python Variables
Variables are containers for storing data values. Python has no command for declaring a variable. A variable is created the moment you first assign a value to it.
For Example:
X=10
Y=’’Jhon”
Print(x)
Print(y)
Output:
10
Jhon
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Python For Loops
A for loop is used for iterating over a sequence (that is either a list, a tuple, a dictionary, a set, or a string). This is less like the for keyword in other programming languages, and works more like an iterator method as found in other object-orientated programming languages. With the for loop we can execute a set of statements, once for each item in a list, tuple, set etc.
Example:
fruits = ["apple", "banana", "cherry"]
for x in fruits:
print(x)
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Python Functions
A function is a block of code which only runs when it is called. You can pass data, known as parameters, into a function. A function can return data as a result.
Example:
def my_function():
print("Hello from a function")
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Arguments:
Information can be passed into functions as arguments. Arguments are specified after the function name, inside the parentheses. You can add as many arguments as you want, just separate them with a comma. The following example has a function with one argument (fname). When the function is called, we pass along a first name, which is used inside the function to print the full name:
def b(fname):
Print(fname )
b("america")
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Number of Arguments:
By default, a function must be called with the correct number of arguments. Meaning that if your function expects 2 arguments, you have to call the function with 2 arguments, not more, and not less.
Example:
Def a(fname, lname)
Print(fname + lname)
a(“Aelina”+ “” +”Rai”)
Output: Aelina Rai
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Python Lambda
A lambda function is a small anonymous function. A lambda function can take any number of arguments, but can only have one expression.
Syntax:
lambda arguments: expression
The expression is executed and the result is returned:
For example:
Add 10 to argument a, and return the result:
x = lambda a : a + 10
print(x(5))
Lambda functions can take any number of arguments:
Example
Multiply argument a with argument b and return the result:
x = lambda a, b : a * b
print(x(5, 6))
Example
Summarize argument a, b, and c and return the result:
x = lambda a, b, c : a + b + c
print(x(5, 6, 2))
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Python Arrays
An array is a special variable, which can hold more than one value at a time. Arrays are used to store multiple values in one single variable:
Example
Create an array containing car names:
cars = ["Ford", "Volvo", "BMW"]
Example
Get the value of the first array item:
x = cars[0]
The Length of an Array:
Use the len() method to return the length of an array (the number of elements in an array).
Example
Return the number of elements in the cars array:
x = len(cars)
Looping Array Elements:
You can use the for in loop to loop through all the elements of an array.
Example
Print each item in the cars array:
for x in cars:
print(x)
Adding Array Elements:
You can use the append() method to add an element to an array.
Example
Add one more element to the cars array:
cars.append("Honda")
Removing Array Elements:
You can use the pop() method to remove an element from the array.
Example
Delete the second element of the cars array:
cars.pop(1)
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