Python beginner string

                    PYTHON STRING

                                 2^nd Part

This is our python string second part. So, Let’s get coding.

You want to search a word from your string. I give you a 1000 text 

file. You want to search your favorite word. How you search this.?

Python has a find() method. Let’s give you a couple of examples.

>>> country = “Bangladesh”

>>> country.find(‘Bangla’)

0

find() method return which position you find ‘Bangla’ string.

you find method found ‘Bangla’ in 0 positions. Again, I give

you the scenario.

B a n l a d e s h

0 1 2 3 4 5 6 7 8

so, when you put ‘Bangla’ in find method, it starts position 0. 

That’s why it returns zero. Now, if I give ‘abc’, then find method 

returns -1.That means find method does not found your ‘abc’ in 

‘Bangladesh’.

>>> country.find(‘abc’)

-1

>>> full_name=”iftekharul islam”

>>> full_name

>>> full_name.find(‘tekharul’)

2

why two? I said that it always start the first position. What is 

‘t’ index number in full_name. Think again. I know you know the

answer. you are the best. Yeah, ‘t’ index number is 2.

i f t e k h a r u l

0 1 2 3 4 5 6 7 8 9

Now, you can ask me why ‘.find()’. Why you use dot(.)?. Good 

question.Here the country is an object. The string is an object. 

String object has a many methods. We discuss object later.

replace() method

Now we want to change string inside. Really? How?
>>> Boyfriend = “messi”

>>> Boyfriend.replace(‘messi’,’ronaldo’)
'ronaldo'

you can use variable

>>> ex_girl = “shakira”

>>> current_girl=”Laila”

>>> ex_girl.replace(ex_girl,current_girl)

‘Laila’

>>> ex_girl

‘shakira’

Here, ex_girl still same. When I use replace method ex_girl or

Boyfriend example, replace() method make new string and then return

it. But main string ex_girl does not change.

>>> country = ‘Bangladesh’

>>> new_country = country.replace(‘B’,’b’)

>>> new_country

‘bangladesh’

>>> country

‘Bangladesh’

I am finishing here. I will write string last part. So, stay tune

with me. God Bless you.