Difference between revisions of "BASH/C2/More-on-Arrays/English-timed"

|'''Time'''

|'''Narration'''

|  Welcome to the '''spoken tutorial''' on '''More on Arrays''' in '''BASH'''.

| In this tutorial, we will learn to:

|00:10

|Extract an element from an ''' array'''

|00:13

|Replace an element in an ''' array'''  

| 00:16

| Add an element to an ''' array''' and

|00:19

|Remove an element from an ''' array'''.

|00:22

|To follow this tutorial, you should be familiar with the '''Linux Operating System.'''

|00:28

|If not, for relevant tutorials, please visit our website which is as shown.

|00:34

|For this tutorial, I am using '''Ubuntu Linux 12.04''' OS and

|00:41

|'''GNU Bash''' version '''4.1.10'''

| '''GNU Bash '''version 4 or above is recommended for practice.

| Let us see how to extract an '''element''' from an '''array'''.

| The elements in an ''' array''' can be extracted from any position.

| Here, position is the '''index number'''.

| Note that ''' index number''' always starts from zero.

| '''ArrayName''' within square bracket "At" sign colon '''position''' colon '''Number of elements''' to be extracted from the position mentioned.

| Open the '''terminal''' by pressing '''Ctrl+Alt''' and '''T''' keys simultaneously on your keyboard.

| Type:  '''gedit''' space''' array2.sh''' space & (ampersand sign). Press '''Enter.'''

|  Now type the '''code''' as shown here, in your "array2.sh" file.

| This is the ''' Shebang line'''.

| This''' "declare" command ''' declares an '''array ''' named '''Linux ''' with elements-

| "Debian", "Redhat"

| "Ubuntu" and "Fedora".

| This '''"echo" command''' will '''print''' the list of all the elements in the '''array'''.

| The next''' "echo" command''' will print the extracted elements.

| The command '''<nowiki>${Linux[@]:1:2}</nowiki>''' will print two elements starting from index 'one' which is "Redhat".

| First, let's make the file executable by typing '''chmod''' space '''plus x space array2.sh'''. Press '''Enter.'''

|  Type: '''dot slash array2.sh''' press '''Enter.'''

|  We get the output -''' "Original elements in an array Linux: Debian Redhat Ubuntu Fedora".'''

|''' "The two elements starting from index one(Redhat): Redhat Ubuntu".'''

| Let us switch back to the '''slides'''.

| We will see how to replace an element in an '''array''' .

| An existing element in an '''array''' can be replaced using the following syntax.

| '''ArrayName''' within square brackets 'n' equals to within single quote '''NewWord.'''

| Here 'n' is the '''index number''' or '''element number.'''

| Come back to our '''text editor'''.

|  '''Linux[2]='Mandriva'''' .

| This command will replace the third element "Ubuntu" with "Mandriva".

| This '''echo''' command will display all elements of array '''Linux''' after replacement.

| Let's '''execute''' again.

| This displays- "All elements after replacement : Debian Redhat Mandriva Fedora" .

| Now, switch to the '''slides'''.

| We will see how to add an '''element''' to an '''array'''.

| '''ArrayName''' equal to opening round bracket within double quotes dollar sign opening curly bracket '''ArrayName''' opening square bracket "At" sign closing square bracket closing curly bracket space within double quotes '''New_Word_1''' space within double quotes '''New_Word_2''' and closing round bracket.

|  Let us understand this with the help of one example.  

| The highlighted '''command''' will '''append ''' a new element''' "Suse" ''' to the '''array Linux'''.

| Then we will '''echo''' all the elements after appending "Suse".

| Switch to the '''terminal'''.

| Let me clear the '''prompt'''.

| We will '''execute''' the program again.

| The '''output''' is displayed: '''All elements after appending Suse : Debian Redhat Mandriva Fedora and Suse.'''

| Now, come back to our '''slides'''.

| We will see how to remove an '''element''' from an '''array.'''

| '''unset space ArrayName''' opening square bracket '''index number''' closing square bracket.

| Here, we are using the '''unset''' '''command.'''

| And we will remove the third element''' Mandriva''' from the array '''Linux.'''

| Now switch to the '''terminal'''.

| We will '''execute''' the program.

| Here is the list of elements after removing  '''Mandriva'''.

| '''Debian Redhat Fedora''' and  '''Suse'''

| Come back to our '''slides'''.

|-

| In this tutorial, we learned to:

|Extract an element from an''' array'''

|Replace an element in an''' array'''  

|Add element to an''' array''' and

|Remove element from an''' array'''.

| As an assignment- # Declare an array '''names2''' of length 7 and perform following operations.

|Extract three elements, starting from index two.

|Replace third element with '''Debian''' and display.

| Append any new name at the end of array.

| Watch the video available at the link shown below.

| It summarizes the Spoken Tutorial project.

| If you do not have good bandwidth, you can download and watch it.

| The Spoken Tutorial Project team:

|Conducts workshops using spoken tutorials.

|Gives certificates to those who pass an online test.

| '''Spoken Tutorial''' Project is a part of the '''Talk to a Teacher''' project.

| It is supported by the National Mission on Education through ICT, MHRD, Government of India.

| More information on this mission is available at the link shown below.

| The script has been contributed by FOSSEE and spoken-tutorial teams.

| This is Ashwini Patil from IIT Bombay, signing off.