1
00:00:00 --> 00:00:04
Hello friends and welcome to this tutorial on 'Input/Output'.

2
00:00:05 --> 00:00:19
At the end of this tutorial,you will be able to,

 Print some value.

 Print using modifiers.

 Take input from user.

 Display a prompt to the user before taking the input.

3
00:00:20 --> 00:00:25
So type ipython in the terminal.

4
00:00:26 --> 00:00:44
Type a = within double quotes This is a string
 Type a
 Type print a

5
00:00:45 --> 00:00:51
obviously,  print a , prints the value of a .

6
00:00:52 --> 00:00:58
As you can see, even when you type just a, the value of a is shown.

7
00:00:59 --> 00:01:00
But there is a difference.

8
00:01:01 --> 00:01:07
Typing just   a  displays the content of  a  whereas the statement  print a  prints the string itself.

9
00:01:08 --> 00:01:13
This difference becomes more evident when we use strings with newlines in them.

10
00:01:14 --> 00:01:34
Type b =  within double quotes A line backslash n New line and hit enter
Type b
Type print b

11
00:01:35 --> 00:01:45
As you can see, just typing  b  shows that b contains a newline character but While typing print b,it prints the string and hence the newline.

12
00:01:46 --> 00:01:59
Moreover when we type just  a , the value a is shown only in interactive mode and does not have any effect on the program while running it as a script.

13
00:02:00 --> 00:02:03
We shall look at different ways of outputting the data.

14
00:02:04 --> 00:02:07
print statement in python supports string formatting.

15
00:02:08 --> 00:02:11
Various arguments can be passed to print using modifiers.

16
00:02:12 --> 00:02:50
type x = 1.5
      y = 2
      z = within double quotes red
      print  then in double quotes x is modula 2 dot 1f comma  y is modula d comma  z is modula s then again a modula within brackets x comma y comma z

17
00:02:51 --> 00:03:02
As you can see, the values of x, y and z are substituted in place of the modifiers modula 2.1f, modula d and modula s respectively.

18
00:03:03 --> 00:03:07
Pause the video here, try out the following exercise and resume the video.

19
00:03:08 --> 00:03:18
What happens when you do print  within double quotes x is modula d comma  y is modula f modula  x comma  y

20
00:03:19 --> 00:03:23
Switch to the terminal for solution.

21
00:03:24 --> 00:03:49
Type print  within double quotes x is modula d comma  y is modula f modula within brackets x comma  y

22
00:03:50 --> 00:03:57
We see that the int value of x and float   value of y are printed corresponding to the modifiers used in the print statement.

23
00:03:58 --> 00:04:03
We have seen that print statement prints a new line character every time it is called.

24
00:04:04 --> 00:04:12
This can be suppressed by using a " comma " at the end of the print statement.

25
00:04:13 --> 00:04:23
Let us see this by typing out following code on an editor as print underscore example.py

26
00:04:24 --> 00:04:43
So Type..

27
00:04:44 --> 00:05:21
print "Hello"
print "World"

print "Hello" comma 
print "World"

28
00:05:22 --> 00:05:33
Save the script as 'print underscore example.py' and run it using modula run  slash home slash fossee slash print underscore example.py

29
00:05:34 --> 00:05:45
As we can see, the print statement when used with comma in the end, prints a space instead of a new line.

30
00:05:46 --> 00:06:05
Now we shall look at taking input from the user.

31
00:06:06 --> 00:06:10
We will use the ~~raw underscore input~~ for this.

32
00:06:11 --> 00:06:22
So type ip = raw underscore input()

33
00:06:23 --> 00:06:31
The cursor is blinking indicating that it is waiting for input, so type something and hit enter.

34
00:06:32 --> 00:06:34
So you can type an input

35
00:06:35 --> 00:06:40
Now let us see what is the value of ip by typing it.

36
00:06:41 --> 00:06:44
So type ip on the terminal and hit enter

37
00:06:45 --> 00:06:50
We can see that it contains the string "an input"

38
00:06:51 --> 00:06:57
Pause the video here, try out the following exercise and resume the video.

39
00:06:58 --> 00:07:01
You have an question

40
00:07:02 --> 00:07:10
Enter the number 5.6 as input and store it in a variable called c.

41
00:07:11 --> 00:07:14
Switch to the terminal for solution.

42
00:07:15 --> 00:07:18
We have to use the raw underscore input command with variable c.

43
00:07:19 --> 00:07:35
So type c = raw underscore input() and hit enter
Put 5.6
And again enter.
Type c

44
00:07:36 --> 00:07:39
Now let us see the type of c.

45
00:07:40 --> 00:07:45
Type type within brackets c

46
00:07:46 --> 00:07:48
We see that c is a string.

47
00:07:49 --> 00:07:54
This implies that anything you enter as input, it will be taken as a string no matter what you enter.

48
00:07:55 --> 00:07:58
Pause the video here, try out the following exercise and resume the video.

49
00:07:59 --> 00:08:03
What happens when you do not enter anything and hit enter.

50
00:08:04 --> 00:08:07
Switch to the terminal for solution.

51
00:08:08 --> 00:08:27
Type d = raw underscore input()
	
	d

52
00:08:28 --> 00:08:31
We see that when nothing is entered, an empty string is considered as input.

53
00:08:32 --> 00:08:36
raw underscore input also can display a prompt to assist the user.

54
00:08:37 --> 00:08:47
So type name = raw underscore input within brackets  within double quotes Please enter your name:

55
00:08:48 --> 00:08:53
It prints the string given as argument and then waits for the user input.

56
00:08:54 --> 00:08:55
Let us do one more exercise.

57
00:08:56 --> 00:08:59
Pause the video here, try out the following exercise and resume the video.

58
00:09:00 --> 00:09:08
How do you display a prompt and let the user enter input in next line.

59
00:09:09 --> 00:09:11
Switch to the terminal now.

60
00:09:12 --> 00:09:16
The trick is to include a newline character at the end of the prompt string.

61
00:09:17 --> 00:09:27
Type ip = raw underscore input within brackets  within double quotes Please enter a number in the next line backslash n

62
00:09:28 --> 00:09:34
It prints the newline character and hence the user enters input in the next line

63
00:09:35 --> 00:09:38
This brings us to the end of the tutorial.

64
00:09:39 --> 00:09:41
In this tutorial, we have learnt to,1. Use the print statement.

65
00:09:42 --> 00:09:46
2. Use the modifiers modula d, modula f, modula s in the print statement.

66
00:09:47 --> 00:09:54
3. Take input from user by using raw underscore input().

67
00:09:55 --> 00:10:03
4. Display a prompt to the user before taking the input by passing a string as an argument to raw underscore input.

68
00:10:04 --> 00:10:07
Here are some self assessment questions for you to solve

69
00:10:08 --> 00:10:12
1. a = raw underscore input()  and user enters 2.5 .

70
00:10:13 --> 00:10:19
What is the type of a?


 str

 int

 float

 char

71
00:10:20 --> 00:10:26
2. a = 2 and b = 4.5.

72
00:10:27 --> 00:10:49
What does ``print "a is modula d and b is  In line literal start-string without end-string. modula 2.1f" modula within brackets b comma a`` print?


 a is 2 and b is 4.5

 a is 4 and b is 2

 a is 4 and b is 2.0

 a is 4.5 and b is 2

73
00:10:50 --> 00:10:52
And the answers,

74
00:10:53 --> 00:10:57
1.No matter what you enter, it will be taken as a string.

75
00:10:58 --> 00:11:00
Hence 2.5 is a string.

76
00:11:01 --> 00:11:09
2. Since 'b' is called first, It will display integer value of 'a' because the modifier used is modula d.

77
00:11:10 --> 00:11:17
Similarly, 'b' will get the float value of 'a' due to it's modifier modula 2.1f.

78
00:11:18 --> 00:11:23
Hence 'a' will be 4 and 'b' 2.0 .

79
00:11:24 --> 00:11:29
Hope you have enjoyed this tutorial and found it useful.