Python-String Literals(N)

April 23, 2020

Good Morning Boys

Welcome to the 5th session of the online classes for Python Programing.
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Lets look at the solutions for the Exercise given in the last session.
1.   happy_10- This is a valid identifier.
2.   For-This is a valid identifier because although "for" is a reserved word but because here it begins with capital f "F", it cannot be treated as a reserved word. User can use it as an identifier.
3.   for- This is an invalid identifier because it is a reserved word.
4.   10find-This is an invalid identifier because it is begins with a number.
5.   Count- This is a valid identifier as it conforms to the rules of making a valid identifier.
6.   Count 1-This is an invalid identifier because it is has a white space in between which is not allowed.
7.   cout@1- This is an invalid identifier because it uses a special symbol "@" which is not allowed. Only underscore is allowed while creating a valid identifier.
8.   1count-This is an invalid identifier because it is begins with a number.
9.   Count_1- This is a valid identifier as it conforms to the rules of making a valid identifier.
10.  if- This is an invalid identifier because it is a reserved word.
11.  if#-This is an invalid identifier as it is using # , a symbol that is invalid and is not available while creating identifiers.
12.  while- This is an invalid identifier because it is a reserved word.
13.  while 2-This is an invalid identifier because it is has a white space in between which is not allowed.
14.  while_2-This is a valid identifier as it conforms to the rules of making a valid identifier.
15.  while.nd- This is an invalid identifier because it uses a special symbol "." which is not allowed. Only underscore is allowed while creating a valid identifier.
16.  while2-This is a valid identifier as it conforms to the rules of making a valid identifier.

I hope the concept is clear. Doubts if any, can be shared in the comments section.
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Lets start the topic for the day.- "Strings in Python"

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By the end of the session, you will be able to

Understand the string data type
definition and purpose of string data type
Ways to print strings
Apply the concatenation operator and repetition operators and predict the output.

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All of you are expected to copy the notes shared on the blog today.

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Python Strings

Strings in Python are identified as a contiguous set of characters represented in the quotation marks.
Python allows for either pairs of single or double quotes.
Example:

"Geeta", 'Pratham', "1234", '786'

Two types of strings supported in Python

Single Line String

Strings that are terminated in within a single line.

For example:

Let's work on a SINGLE LINE STRING ==>>> "Hello, How are you?"

Output will be:

Multiline string

Piece of text that is spread along multiple lines
(i.e. it covers more than one line)

There are two ways to create Multiline Strings:

Adding backslash (" \ ") at the end of each line.

For example: working on string ==>> "Hello, How are you?"
in a Multiline format using backslash (" \ ")

The Output will be:

Using Triple quotation marks ("""):

To create Multiline strings, we can also use three single/double quotes.

For example: working on string ==>> "Hello, How are you?"
in a Multiline String format using Triple quotation marks (""")

The Output will be :

Boys... You must have seen the outputs by both the methods

In First Method (i.e. by using backslash (" \ ") -- Even after writing the string in different lines we got the output on one single line as:
Hello, How are you?

In Second Method (i.e. by using triple quotation marks ( """) -- We got the output same as we typed. i.e.:
Hello,
How
are you?

When we want the output to be exactly as we type, then we must use triple quotation marks ( """).

In addition to this, we can work on Strings using following characters...

The plus (+) sign is the string concatenation operator.

The asterisk (*) is the repetition operator.

---------------------------------------------------------------------------------------------------------------------------------For example −

#!/usr/bin/python

str = 'Hello World!'

print str          # Prints complete string
print str * 2      # Prints string two times
print str + "TEST" # Prints concatenated string

This will produce the following result −

Hello World!
Hello World!Hello World!
Hello World!TEST

EXERCISE



What can you say about the string data type?


Is there a difference between "Geeta" and 'Geeta'? Justify.


Predict the output of the following:


print("SCS"*5)


print(("SCS"," ")*5)


print("I"+"Love"+"Columbas")


print("I","Love","Columbas")




Suppose 

           str='I LOVE COLUMBAS'

Predict the output of the following:

print str          # Prints complete string
print str * 2      # Prints string two times
print str + " MUSIC"

You are requested to first try to predict the output based on your understanding and then try to check on the computer.

God Bless You

Computer Science Department
(Middle School)

Edited_Python-Strings.txt Displaying Edited_Python-Strings.txt.