Pratik kamble: Created page with "{| border =1 | '''Time ''' |'''Narration''' |- | 00:01 | Welcome to the spoken tutorial on '''Manipulating''' '''Strings'''. |- | 00:06 |In this tutorial, we will learn to..."

2019-06-04T12:41:39Z

Created page with "{| border =1 | '''Time ''' |'''Narration''' |- | 00:01 | Welcome to the spoken tutorial on '''Manipulating''' '''Strings'''. |- | 00:06 |In this tutorial, we will learn to..."

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{| border =1
| '''Time '''
|'''Narration'''

|-
| 00:01
| Welcome to the spoken tutorial on '''Manipulating''' '''Strings'''.

|-
| 00:06
|In this tutorial, we will learn to

Slice a '''string''' and get '''substrings''' out of them

Reverse a '''string'''

Replace characters in a '''string'''

Convert a '''string''' to upper or lowercase and

Join '''list''' '''elements''' to form a '''string'''

|-
| 00:27
| To record this tutorial, I am using

'''Ubuntu Linux 16.04''' operating system

'''Python 3.4.3''' and

'''IPython 5.1.0'''

|-
|00:43
|To practise this tutorial, you should know how to use

'''basic datatypes, operators, strings '''and '''lists'''

If not, see the relevant '''Python''' tutorials on this website.

|-
| 00:59
| First let us see about '''string slicing'''.

|-
| 01:03
| '''String slicing '''allows us to obtain '''substrings'''.

|-
| 01:08
| The syntax for the string slicing is:

'''string_name '''''inside square brackets '''''start '''''colon''''' stop '''or

'''string_name '''''inside square brackets '''''start '''''colon '''''stop '''''colon '''''step'''

|-
| 01:24
| Let us start '''ipython'''. Open the '''terminal.'''

|-
| 01:29
| Type '''ipython3 '''and press '''Enter.''' From here onwards, remember to press the '''Enter''' key after typing every command on the '''terminal'''.

|-
| 01:40
| Let us understand the '''string slicing''' with an example. Type, '''data '''''is equal to inside double quotes''''' python'''

|-
| 01:51
| Type, '''print '''''inside brackets '''''data '''''inside square brackets '''''0 '''''colon '''''3'''

|-
| 01:59
| We get the '''sliced substring''' as '''pyt.'''

|-
| 02:03
| Note that, we are '''slicing''' the '''string''' from the '''index''' 0 to 3.

|-
| 02:09
| By doing so, the string elements from index 3 are not included.

|-
| 02:15
| Let us create a '''list, week''''' underscore '''''name '''which has names of the days of the week.

|-
|02:21
|Type as shown. Type, '''s '''''is equal to inside double quotes''''' saturday'''

|-
| 02:31
| We need to check if the first three characters of the given '''string''' exists in the list''' week''''' underscore '''''name'''.

|-
| 02:39
| '''Strings''' can be '''sliced''' into '''substrings'''.

|-
|02:43
|To get the first three characters of the string '''s''', type, '''s '''''inside square brackets '''''0 '''''colon '''''3'''

|-
| 02:52
| As you can see, the character at last index ie '''3''' is not included in the sliced output.

|-
| 03:00
| We will check if the '''substring '''of''' s '''is present in the '''list''' '''week''''' underscore '''''name.'''

|-
| 03:06
| Type '''s '''''inside square brackets '''''0 '''''colon '''''3 in week''''' underscore '''''name'''

|-
| 03:14
| We get the output as '''True''' which indicates that the substring is present in the list.

|-
| 03:20
| Pause the video. Try this exercise and then resume the video.

|-
| 03:26
| Obtain the '''substring''' excluding the first and last characters from the '''string''' '''s'''.

|-
| 03:32
| Switch back to '''terminal''' for the solution.

|-
| 03:36
| Type, '''s '''''inside square brackets '''''1 '''''colon '''''-1'''

|-
| 03:42
| As we already know, the last element of the '''string''' can be accessed using the index''' -1'''.

|-
| 03:49
| Next let us learn to check if a given '''string''' is a '''palindrome''' or not.

|-
| 03:55
| A '''palindromic string''' is a '''string''' that is same as its reverse.

|-
| 04:01
| Type, '''s1 '''''is equal to inside double quotes''''' dad'''

|-
| 04:07
| Now, we need to compare this '''string''' with its reverse.

|-
| 04:11
| For reversing '''s1''', we '''stride''' the '''string''' from the first to last '''character.'''

|-
| 04:17
| It is done''' '''by keeping the '''start''' and '''stop''' values as empty and '''step''' as -1.

|-
| 04:24
| That is '''s1 '''''inside square brackets colon colon''''' -1'''

|-
| 04:30
| Now, we will check if the string '''s1''' is a '''palindrome''' or not.

|-
| 04:35
| Type, '''s1''''' is double equal to''''' s1 '''''inside square brackets colon colon '''''-1'''

|-
| 04:44
| The output '''True '''indicates that it is a '''palindrome'''.

|-
| 04:49
| If the given '''string''' has capital '''D '''in''' dad''' instead of small '''d''', the comparison would return '''False'''.

|-
| 04:57
| So, we have to convert the '''string''' to all '''lowercase''' or '''uppercase''', before comparison.

|-
| 05:04
| '''Python''' provides the '''string''' '''methods''' '''lower''' and '''upper''' to achieve this.

|-
| 05:10
| Let's try it out. Type, '''s2 '''''is equal to inside double quotes''''' '''capital''' D ad'''

|-
| 05:19
| Type '''s2.upper '''open and close parentheses We get all the '''characters''' in '''uppercase'''.

|-
| 05:29
| Type '''s2''' As you can see, '''s2''' has not changed.

|-
| 05:36
| It is because, '''method upper''' returns a new '''string'''. It doesn't change the original '''string'''.

|-
| 05:43
| Let us compare the original and reversed '''string''' in '''lowercase.'''

Type as shown. As expected the output is '''True'''.

|-
| 05:56
| Pause the video. Try this exercise and then resume the video.

|-
| 06:02
| Check if each '''element''' in the following '''list '''is present in the '''list''' '''week''''' underscore '''''name'''.

|-
| 06:09
| Switch back to '''terminal''' for the solution.

|-
| 06:13
| Type as shown. It returns '''False''' for '''python '''as it is not there in the '''list week''''' underscore '''''name.'''

|-
| 06:24
| Next let us learn to use '''replace method'''.

|-
| 06:28
| Type, '''email '''''is equal to inside double quotes '''''info[at]fossee[dot]in'''

|-
| 06:36
| We often encounter '''email addresses''' which have '''@''' '''symbol '''and '''periods''' replaced with text as shown.

|-
| 06:44
| Let us learn how to get back proper '''email''' '''addresses'''.

|-
|06:49
| Now, we will first replace the '''[at]''' with the '''@ symbol''', using the '''replace method'''.

|-
| 06:55
| Type as shown. You can see that the '''@ symbol '''is properly replaced now.

|-
| 07:05
| Pause the video. Try this exercise and then resume the video.

|-
| 07:11
| Replace the '''[dot] '''with ''''.'''' symbol in the given '''email.'''

|-
| 07:16
| Switch back to '''terminal''' for the solution.

|-
| 07:20
| Type as shown.

|-
| 07:24
| Now the variable '''email''''' underscore '''''proper''' has the '''email '''in the proper form.

|-
| 07:30
| Next, we will look at another interesting problem.

|-
| 07:34
| Let us say, we have a list of '''email addresses''' in the variable '''email''''' underscore '''''list''' as shown.

|-
| 07:41
| We will obtain one long '''string''' of '''email addresses,''' separated by '''commas''' or '''semicolons'''.

|-
|07:48
| We will use the '''string method join '''for joining the '''list items '''into a single '''string.'''

|-
| 07:55
| Type as shown. '''Comma''' followed by a '''space''' will give the '''string''' with the same '''formatting'''.

|-
| 08:04
| Type, '''print '''''inside parentheses''''' email''''' underscore '''''str''' You can see that all the email addresses joined into a single '''string'''.

|-
| 08:16
| Pause the video. Try this exercise and then resume the video.

|-
| 08:22
| From the '''email''''' underscore '''''str''', change the separator to '''semicolon''' instead of '''comma'''.

|-
| 08:29
| Switch back to '''terminal''' for the solution.

|-
| 08:33
|Type as shown. We see that the email addresses are joined by a semicolon followed by a space.

|-
| 08:43
| This brings us to the end of this tutorial. Let us summarize.

|-
|08:49
|In this tutorial, we have learnt to,

Obtain '''substrings'''

Reverse '''strings''' by using the index numbers

|-
| 08:58
|Use the following methods

'''upper()'''

'''lower()'''

'''replace() '''and

'''join()'''

|-
| 09:05
| Here are some self assessment questions for you to solve

1. Given a string '''s = "this was a string”''', how will you change it to "'''this wasn't a list'''"?

2. The string '''s''' is assigned as shown, change the string to "'''friends'''"

|-
| 09:25
| And the answers,

1. We will use the '''replace''' '''method''' to accomplish this.

Here '''string''' and '''was''' in the statement will be replaced by '''list''' and '''wasn't '''respectively.

|-
| 09:39
| 2. In order to remove dots and to get '''substring '''we '''stride '''the '''string s'''.

|-
| 09:45
| To change the '''string''' to '''lowercase''', we use the '''string method lower().'''

|-
| 09:51
| Please post your timed queries in this forum.

|-
| 09:55
| Please post your general queries on Python in this forum.

|-
| 10:00
| FOSSEE team coordinates the TBC project. (16.45)

|-
| 10:04
| Spoken Tutorial Project is funded by NMEICT, MHRD, Govt. of India. For more details, visit this website.

|-
| 10:14
| This is Priya from IIT Bombay signing off. Thanks for joining.

|}

Python-3.4.3/C3/Manipulating-strings/English-timed - Revision history

Pratik kamble: Created page with "{| border =1 | '''Time ''' |'''Narration''' |- | 00:01 | Welcome to the spoken tutorial on '''Manipulating''' '''Strings'''. |- | 00:06 |In this tutorial, we will learn to..."