Python Programming - Class #3

Strings

Concatenation:-

Concatenation is the process of Combining two strings.

We use “+” symbol to concatenate two strings.

For Example:-

think = "Think"

python = 'Python'

think_python = think + ' ' + python

print(think_python)

String Multiplication:-

Python Language support the Property of String Multiplication.We can multiply the the String.

For Example:-

love = "love"

fifteen_of_love = love * 10

print(fifteen_of_love)

String Indexing:-

We can access any character of string by using index number of that character.

For Example:-

python = "Python"

print("o " + python[4])     # Note: string indexing starts with 0

p_letter = python[0]

print(p_letter) 

String Negative Indexing:-

We can also use the negative indexing to access the Desired character by counting “Backword” the string.

For Example:-

long_string = "This is a very long string!"

g_word = long_string[-2]

print(g_word)

String Slicing:-

String Slicing is used to convert a long string into Sub Strings.We can divide a long string into Sub Strings.We can also divide more then one character by using Slicing.

str[start:end] # items start through end-1

str[start:]    # items start through the rest of the array

str[:end]      # items from the beginning through end-1

str[:]         # a copy of the whole array

For Example:-

think_python = "Think Python"

think = think_python[:5]      # one or both index could be dropped. think_python[:5] is equal to monty_python[0:5]

print(think)

python = think_python[6:]

print(python)

In Operator:-

We can search any character by using “in operator” in a string.

For Example:-

think_python = "think python"

print("think" in think_python)    # print boolean result directly

contains = 'python' in think_python

print(contains)

String Length:-

We can use the “len()” function to calculate the length of a string.

For Example:-

pakistan = "I love Pakistan"

print(len(pakistan))

Basic String Method:-

There are a lot of methods in Python Programming.We can use lowers() and Uppers() function to write the String in Lower case or Upper Case..

For Example:-

love_python = "I Love Python"

print(love_python)

print(love_python.lower())    # print lower-cased version of the string

print(love_python.upper())