10 .. ------------- |
10 .. ------------- |
11 |
11 |
12 .. 1. Loops |
12 .. 1. Loops |
13 |
13 |
14 .. Author : Nishanth Amuluru |
14 .. Author : Nishanth Amuluru |
15 Internal Reviewer : |
15 Internal Reviewer : Puneeth |
16 External Reviewer : |
16 External Reviewer : |
17 Checklist OK? : <put date stamp here, if OK> [2010-10-05] |
17 Checklist OK? : <put date stamp here, if OK> [2010-10-05] |
18 |
18 |
19 Script |
19 Script |
20 ------ |
20 ------ |
21 |
21 |
22 Hello friends and welcome to the tutorial on Input/Output |
22 Hello friends and welcome to this tutorial on Input/Output |
23 |
23 |
24 {{{ Show the slide containing title }}} |
24 {{{ Show the slide containing title }}} |
25 |
25 |
26 {{{ Show the slide containing the outline slide }}} |
26 {{{ Show the slide containing the outline slide }}} |
27 |
27 |
28 Input and Output are used in almost every program we use. |
28 Input and Output are used in almost every program we use. |
29 In this tutorial, we shall learn |
29 In this tutorial, we shall learn how to |
30 |
30 |
31 * Outputting data |
31 * Output data |
32 * Taking input from the user |
32 * Take input from the user |
33 |
33 |
34 type |
34 type |
35 :: |
35 :: |
36 |
36 |
37 a = "This is a string" |
37 a = "This is a string" |
38 a |
38 a |
39 print a |
39 print a |
40 |
40 |
41 print a prints the value of a which is obvious. |
41 |
|
42 ``print a``, obviously, is printing the value of ``a``. |
|
43 |
42 As you can see, even when you type just a, the value of a is shown. |
44 As you can see, even when you type just a, the value of a is shown. |
43 But there is a difference. |
45 But there is a difference. |
|
46 |
|
47 .. #[Amit: The next sentence does seem to be clear enough] |
44 |
48 |
45 Typing a shows the value of a while print a prints the string. This difference |
49 Typing a shows the value of a while print a prints the string. This difference |
46 becomes more evident when we use strings with newlines in them. |
50 becomes more evident when we use strings with newlines in them. |
47 type |
51 type |
48 :: |
52 :: |
55 While typing print b prints the string and hence the newline. |
59 While typing print b prints the string and hence the newline. |
56 |
60 |
57 Moreover when we type just a, the value a is shown only in interactive mode and |
61 Moreover when we type just a, the value a is shown only in interactive mode and |
58 does not have any effect on the program while running it as a script. |
62 does not have any effect on the program while running it as a script. |
59 |
63 |
|
64 .. #[punch: I think we could show that?] |
|
65 |
60 We shall look at different ways of outputting the data. |
66 We shall look at different ways of outputting the data. |
61 |
67 |
62 print statement also accepts the syntax of C's printf statement. |
68 |
|
69 .. #[Amit: C's printf syntax ?? i think its better to elaborate the |
|
70 idea] |
|
71 |
|
72 print statement in python supports string formatting. |
63 Various arguments can be passed to print using modifiers. |
73 Various arguments can be passed to print using modifiers. |
|
74 |
64 type |
75 type |
65 :: |
76 :: |
66 |
77 |
67 x = 1.5 |
78 x = 1.5 |
68 y = 2 |
79 y = 2 |
69 z = "zed" |
80 z = "zed" |
70 print "x is %2.1f y is %d z is %s"%(x,y) |
81 print "x is %2.1f y is %d z is %s"%(x,y) |
71 |
82 |
72 As you can see, the values of x and y are substituted in place of %2.1f and %d |
83 As you can see, the values of x and y are substituted in place of |
|
84 ``%2.1f`` and ``%d`` |
73 |
85 |
74 {{{ Pause here and try out the following exercises }}} |
86 {{{ Pause here and try out the following exercises }}} |
75 |
87 |
76 %% 1 %% What happens when you do ``print "x is %d y is %f" %(x, y)`` |
88 %% 1 %% What happens when you do ``print "x is %d y is %f" %(x, y)`` |
77 |
89 |
78 {{{ continue from paused state }}} |
90 {{{ continue from paused state }}} |
79 |
91 |
80 We see that the int value of x and float value of y are printed corresponding |
92 We see that the ``int`` value of x and ``float`` value of y are |
81 to the modifiers used in the print statement. |
93 printed corresponding to the modifiers used in the print statement. |
82 |
94 |
83 We can also see that print statement prints a new line character at the end of |
95 We can also see that ``print`` statement prints a new line character |
84 line, everytime it is called. This can be suppressed by using a "," at the end |
96 at the end of the line, everytime it is called. This can be suppressed |
85 print statement. |
97 by using a "," at the end ``print`` statement. |
86 |
98 |
87 Let us see this by typing out following code on an editor as print_example.py |
99 Let us see this by typing out following code on an editor as print_example.py |
88 |
100 |
89 {{{ open an editor }}} |
101 {{{ open an editor }}} |
90 type |
102 type |
166 |
178 |
167 prints the string given as argument and then waits for the user input. |
179 prints the string given as argument and then waits for the user input. |
168 |
180 |
169 {{{ Pause here and try out the following exercises }}} |
181 {{{ Pause here and try out the following exercises }}} |
170 |
182 |
171 %% 4 %% How do you display a prompt and let the user enter input in a new line |
183 %% 4 %% How do you display a prompt and let the user enter input in next line |
172 |
184 |
173 {{{ continue from paused state }}} |
185 {{{ continue from paused state }}} |
174 |
186 |
175 .. #[Puneeth: We didn't talk of new-line character till now, did we?] |
187 .. #[Puneeth: We didn't talk of new-line character till now, did we?] |
176 .. #[Puneeth: non-programmers might not know?] |
188 .. #[Puneeth: non-programmers might not know?] |
177 |
189 |
|
190 .. #[Amit: Well there is a discussion earlier about new lines, I think its good |
|
191 .. as a slight trick question. But may be next line is a more easier lexicon] |
|
192 |
178 The trick is to include a newline character at the end of the prompt string. |
193 The trick is to include a newline character at the end of the prompt string. |
179 :: |
194 :: |
180 |
195 |
181 ip = raw_input("Please enter a number in the next line\n> ") |
196 ip = raw_input("Please enter a number in the next line\n> ") |
182 |
197 |
183 prints the newline character and hence the user enters input in the new line |
198 prints the newline character and hence the user enters input in the next line |
184 |
199 |
185 {{{ Show summary slide }}} |
200 {{{ Show summary slide }}} |
186 |
201 |
187 This brings us to the end of the tutorial. |
202 This brings us to the end of the tutorial. |
188 we have learnt |
203 In this totorial we have learnt |
189 |
204 |
190 * How to print some value |
205 * How to print some value |
191 * How to print using modifiers |
206 * How to print using modifiers |
192 * How to take input from user |
207 * How to take input from user |
193 * How to display a prompt to the user before taking the input |
208 * How to display a prompt to the user before taking the input |
194 |
209 |
195 {{{ Show the "sponsored by FOSSEE" slide }}} |
210 {{{ Show the "sponsored by FOSSEE" slide }}} |
196 |
211 |
197 #[Nishanth]: Will add this line after all of us fix on one. |
212 |
198 This tutorial was created as a part of FOSSEE project, NME ICT, MHRD India |
213 This tutorial was created as a part of FOSSEE project, NME ICT, MHRD India |
199 |
214 |
200 Hope you have enjoyed and found it useful. |
215 Hope you have enjoyed and found it useful. |
201 Thankyou |
216 Thank You. |
202 |
217 |