diff options
Diffstat (limited to 'input_output')
| -rw-r--r-- | input_output/script.rst | 32 | ||||
| -rw-r--r-- | input_output/script.rst.orig | 222 |
2 files changed, 244 insertions, 10 deletions
diff --git a/input_output/script.rst b/input_output/script.rst index b5f994a..b35507d 100644 --- a/input_output/script.rst +++ b/input_output/script.rst @@ -12,7 +12,7 @@ .. 1. Loops .. Author : Nishanth Amuluru - Internal Reviewer : + Internal Reviewer : Puneeth External Reviewer : Checklist OK? : <put date stamp here, if OK> [2010-10-05] @@ -26,10 +26,10 @@ Hello friends and welcome to this tutorial on Input/Output {{{ Show the slide containing the outline slide }}} Input and Output are used in almost every program we use. -In this tutorial, we shall learn +In this tutorial, we shall learn how to - * Outputting data - * Taking input from the user + * Output data + * Take input from the user type :: @@ -38,7 +38,11 @@ type a print a +<<<<<<< local print a, prints the value of a. +======= +``print a``, obviously, is printing the value of ``a``. +>>>>>>> other As you can see, even when you type just a, the value of a is shown. But there is a difference. @@ -59,13 +63,20 @@ While typing print b prints the string and hence the newline. 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. +.. #[punch: I think we could show that?] + We shall look at different ways of outputting the data. +<<<<<<< local .. #[Amit: C's printf syntax ?? i think its better to elaborate the idea] print statement in python supports string formatting. Various arguments can be passed to print using modifiers. +======= +``print`` statement also accepts the syntax of C's ``printf`` statement. +Various arguments can be passed to ``print`` using modifiers. +>>>>>>> other type :: @@ -74,7 +85,8 @@ type z = "zed" print "x is %2.1f y is %d z is %s"%(x,y) -As you can see, the values of x and y are substituted in place of %2.1f and %d +As you can see, the values of x and y are substituted in place of +``%2.1f`` and ``%d`` {{{ Pause here and try out the following exercises }}} @@ -82,12 +94,12 @@ As you can see, the values of x and y are substituted in place of %2.1f and %d {{{ continue from paused state }}} -We see that the int value of x and float value of y are printed corresponding -to the modifiers used in the print statement. +We see that the ``int`` value of x and ``float`` value of y are +printed corresponding to the modifiers used in the print statement. -We can also see that print statement prints a new line character at the end of -line, everytime it is called. This can be suppressed by using a "," at the end -print statement. +We can also see that ``print`` statement prints a new line character +at the end of the line, everytime it is called. This can be suppressed +by using a "," at the end ``print`` statement. Let us see this by typing out following code on an editor as print_example.py diff --git a/input_output/script.rst.orig b/input_output/script.rst.orig new file mode 100644 index 0000000..b35507d --- /dev/null +++ b/input_output/script.rst.orig @@ -0,0 +1,222 @@ +.. Objectives +.. ---------- + +.. #. How to print some value +.. #. How to print using modifiers +.. #. How to take input from user +.. #. How to display a prompt to the user before taking the input + +.. Prerequisites +.. ------------- + +.. 1. Loops + +.. Author : Nishanth Amuluru + Internal Reviewer : Puneeth + External Reviewer : + Checklist OK? : <put date stamp here, if OK> [2010-10-05] + +Script +------ + +Hello friends and welcome to this tutorial on Input/Output + +{{{ Show the slide containing title }}} + +{{{ Show the slide containing the outline slide }}} + +Input and Output are used in almost every program we use. +In this tutorial, we shall learn how to + + * Output data + * Take input from the user + +type +:: + + a = "This is a string" + a + print a + +<<<<<<< local +print a, prints the value of a. +======= +``print a``, obviously, is printing the value of ``a``. +>>>>>>> other +As you can see, even when you type just a, the value of a is shown. +But there is a difference. + +.. #[Amit: The next sentence does seem to be clear enough] + +Typing a shows the value of a while print a prints the string. This difference +becomes more evident when we use strings with newlines in them. +type +:: + + b = "A line \n New line" + b + print b + +As you can see, just typing b shows that b contains a newline character. +While typing print b prints the string and hence the newline. + +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. + +.. #[punch: I think we could show that?] + +We shall look at different ways of outputting the data. + +<<<<<<< local +.. #[Amit: C's printf syntax ?? i think its better to elaborate the + idea] + +print statement in python supports string formatting. +Various arguments can be passed to print using modifiers. +======= +``print`` statement also accepts the syntax of C's ``printf`` statement. +Various arguments can be passed to ``print`` using modifiers. +>>>>>>> other +type +:: + + x = 1.5 + y = 2 + z = "zed" + print "x is %2.1f y is %d z is %s"%(x,y) + +As you can see, the values of x and y are substituted in place of +``%2.1f`` and ``%d`` + +{{{ Pause here and try out the following exercises }}} + +%% 1 %% What happens when you do ``print "x is %d y is %f" %(x, y)`` + +{{{ continue from paused state }}} + +We see that the ``int`` value of x and ``float`` value of y are +printed corresponding to the modifiers used in the print statement. + +We can also see that ``print`` statement prints a new line character +at the end of the line, everytime it is called. This can be suppressed +by using a "," at the end ``print`` statement. + +Let us see this by typing out following code on an editor as print_example.py + +{{{ open an editor }}} +type +:: + + print "Hello" + print "World" + + print "Hello", + print "World" + +Now we run the script using %run /home/fossee/print_example.py + +As we can see, the print statement when used with comma in the end, prints a +space instead of a new line. + +Now we shall look at taking input from the user. +We will use the ~~raw_input~~ for this. +type +:: + + ip = raw_input() + +The cursor is blinking indicating that it is waiting for input +type +:: + + an input + +and hit enter. +Now let us see what is the value of ip by typing. +:: + + ip + +We can see that it contains the string "an input" + +{{{ Pause here and try out the following exercises }}} + +%% 2 %% enter the number 5.6 as input and store it in a variable called c. + +{{{ continue from paused state }}} + +We have to use the raw_input command with variable c. +type +:: + + c = raw_input() + 5.6 + c + +Now let us see the type of c. + +:: + + type(c) + +We see that c is a string. This implies that anything you enter as input, will +be taken as a string no matter what you enter. + +{{{ Pause here and try out the following exercises }}} + +%% 3 %% What happens when you do not enter anything and hit enter + +{{{ continue from paused state }}} + +:: + + d = raw_input() + <RET> + d + +We see that when nothing is entered, an empty string is considered as input. + +raw_input also can display a prompt to assist the user. +:: + + name = raw_input("Please enter your name: ") + +prints the string given as argument and then waits for the user input. + +{{{ Pause here and try out the following exercises }}} + +%% 4 %% How do you display a prompt and let the user enter input in next line + +{{{ continue from paused state }}} + +.. #[Puneeth: We didn't talk of new-line character till now, did we?] +.. #[Puneeth: non-programmers might not know?] + +.. #[Amit: Well there is a discussion earlier about new lines, I think its good +.. as a slight trick question. But may be next line is a more easier lexicon] + +The trick is to include a newline character at the end of the prompt string. +:: + + ip = raw_input("Please enter a number in the next line\n> ") + +prints the newline character and hence the user enters input in the next line + +{{{ Show summary slide }}} + +This brings us to the end of the tutorial. +In this totorial we have learnt + + * How to print some value + * How to print using modifiers + * How to take input from user + * How to display a prompt to the user before taking the input + +{{{ Show the "sponsored by FOSSEE" slide }}} + + +This tutorial was created as a part of FOSSEE project, NME ICT, MHRD India + +Hope you have enjoyed and found it useful. +Thank You. + |