Python/C4/Advanced-features-of-functions/English-timed - Revision history

PoojaMoolya at 07:18, 27 March 2017

2017-03-27T07:18:13Z

PoojaMoolya at 10:58, 20 February 2017

2017-02-20T10:58:52Z

Gaurav at 10:22, 10 July 2014

2014-07-10T10:22:50Z

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Sneha at 06:41, 1 April 2013

2013-04-01T06:41:10Z

Sneha at 11:27, 19 March 2013

2013-03-19T11:27:53Z

Minal: Created page with '{| border=1 !Visual Cue !Narration |- | 0:01 | Hello friends and Welcome to the tutorial on 'advanced features of functions'. |- | 0:06 | At the end of this tutorial, you will b…'

2013-01-02T12:14:54Z

Created page with '{| border=1 !Visual Cue !Narration |- | 0:01 | Hello friends and Welcome to the tutorial on 'advanced features of functions'. |- | 0:06 | At the end of this tutorial, you will b…'

New page

{| border=1
!Visual Cue
!Narration
|-
| 0:01
| Hello friends and Welcome to the tutorial on 'advanced features of functions'.

|-
| 0:06
| At the end of this tutorial, you will be able to,

# Assign default values to arguments, when defining functions.
# Define and call functions with keyword arguments.
# Learn some of the built-in functions available in Python standard library and the scientific computing libraries.

|-
| 0:23
| Before beginning this tutorial,we would suggest you to complete the tutorial on "Getting started with functions".

|-
| 0:32
| Let us Start the ipython interpreter

|-
|0:36
|ipython hypen pylab in command

|-
| 0:43
| Let's use the <tt>round</tt> function as an example to understand what a default value of an argument means.

|-
| 0:49
| Let's type the following expressions in the terminal.

|-
|0:52
|Type round within bracket 2.484 and hit enter.
Then type round within bracket 2.484 comma 2

|-
| 1:10
| Both the first expression and the second are calls to the <tt>round</tt> function, but the first calls it with only one argument and the second calls it with two arguments.

|-
| 1:22
| By observing the output, we can guess that the first one is equivalent to call with the second argument being 0. 0 .

|-
| 1:30
| '''s.strip() # strips on spaces.'''

|-
| 1:35
| s.strip within single quote at the rate # strips the string of 'at the rate' symbols.

|-
| 1:47
| Thus it can be said that here, blank space is the default argument.

|-
| 1:52
| plot within bracket x comma y # plots with x vesus y using default line style. plot within bracket x comma y comma in single quote o # plots x versus y with circle markers.

|-
| 2:14
| Hence, here when third argument is not provided, it shows default line style.

|-
| 2:20
| linspace within bracket 0 comma 2 star pi comma 100 # returns 100 points between 0 and 2pi linspace within bracket 0 comma 2 star pi # returns 50 points between 0 and 2pi

|-
| 2:37
| Hence, the default for the third argument is 50.

|-
| 2:42
| Let's now define a simple function that uses default arguments.

|-
| 2:46
| We define a simple function that prints a welcome message to a person, given a greeting and his/her name.

|-
|2:54
|So type in the terminal def welcome within bracket greet comma name= within double quotes World colon (hit enter)
print greet comma name (hit enter)

|-
| 3:18
| Let us first call the function with two arguments, one for <tt>greet</tt> and other for <tt>name</tt>.

|-
|3:25
|So type welcome within bracket within double quotes Hi comma within double quotes Guido

|-
| 3:35
| We get the expected welcome message, "Hi Guido".

|-
| 3:41
| Now let us call the function with just one argument "Hello".

|-
|3:45
|So type welcome within bracket within double quotes Hello

|-
| 3:53
| "Hello" is treated as the <tt>greet</tt> and we get "Hello World" as the output.

|-
| 3:59
| "World" is the default value for the argument <tt>name</tt>.

|-
| 4:02
| Pause the video here, try out the following exercise and resume the video.

|-
| 4:07
| '''Redefine the function <tt>welcome</tt>, by interchanging it's''' arguments.

|-
| 4:11
| Place the <tt>name</tt> argument with it's default value of "World" before the <tt>greet</tt> argument.

|-
| 4:17
| Switch to the terminal for solution

|-
|4:20
|def welcome within bracket name= within double quotes World comma greet colon (hit enter)
print greet comma name (hit enter)

|-
| 4:36
| We get an error that reads <tt>SyntaxError: non-default argument follows default argument</tt>.Then ipython control line one.

|-
| 4:47
| When defining a function all the argument with default values should come at the end.

|-
| 4:52
| Pause the video here, try out the following exercise and resume the video.

|-
| 4:58
| '''See the definition of linspace using <tt>question mark</tt> and make a note of all''' the arguments with default values are towards the end.

|-
| 5:09
| Switch to the terminal for solution

|-
|5:12
|linspace question mark hit enter

|-
| 5:17
| <nowiki>As we go on hitting the enter key, we the the number of arguments this command has.

|-
| 5:26
| Please read the content on your terminal. <pause></nowiki>

|-
| 5:30
| Again,Pause the video here,try out the following exercise and resume the video.

|-
| 5:35
| '''Redefine the function <tt>welcome</tt> with a default value of'''

|-
| 5:41
| "Hello" to the <tt>greet</tt> argument.

|-
| 5:44
| Then, call the function without any arguments.

|-
| 5:48
| Switch to the terminal for solution

|-
|5:51
|Type def welcome within bracket greet= within double quotes Hello comma name= within double quotes World colon
print greet comma name
(After hitting enter type)
welcome()

|-
| 6:17
| As we can see, we get the output as <tt>Hello World</tt>.

|-
| 6:20
| Let us now learn what keyword arguments or named arguments are.

|-
| 6:26
| We shall refer to them as keyword arguments, henceforth.

|-
| 6:31
| When you are calling functions in Python, you don't need to remember the order in which to pass the arguments.

|-
| 6:38
| Instead, you can use the name of the argument to pass it a value.

|-
| 6:44
| This slide shows a few function calls that use keyword arguments.

|-
| 6:52
| <tt>loc</tt>, <tt>linewidth</tt>, <tt>xy</tt> and <tt>labels</tt> are being called with keyword arguments.

|-
| 7:00
| Let us try and understand this better using the <tt>welcome</tt> function that we have been using all along.

|-
| 7:07
| Let us call it in different ways and observe the output to see how keyword arguments work.

|-
|7:14
|So in terminal type welcome()

welcome within bracket within double quotes Hello comma within double quotes James

welcome within bracket within double quotes Hi comma name= within double quotes Guido

|-
| 7:37
| When no keyword is specified, the arguments are allotted based on their position.

|-
| 7:42
| So, "Hi" is the value of the argument <tt>greet</tt> and name is passed the value "Guido".

|-
| 7:48
| If we type in the terminal welcome within bracket name= within double quotes Guido comma greet= within double quotes Hey exclamation

|-
|8:02
| When keyword arguments are used, the arguments can be called in any order.

|-
| 8:07
| And if we call our function as,welcome within bracket name="Guido" comma "Hey"

|-
| 8:17
| This call returns an error that reads, <tt>non-keyword arg after keyword arg</tt>. Python expects all the keyword to be present towards the end.

|-
| 8:30
| That brings us to the end of what we wanted to learn about <tt>keyword</tt> arguments.

|-
| 8:37
| Before defining a function of your own, make sure that you check the standard library, for a similar function.

|-
| 8:43
| Python is popularly called a "Batteries included" language, for the huge library that comes along with it.

|-
| 8:55
| Math functions - abs, sin, .... Plot functions - plot, bar, pie ... Boolean functions - and, or, not ...

|-
| 9:11
| Apart from the standard library there are other libraries like <tt>pylab</tt>, <tt>scipy</tt>, etc which have a huge collection of functions for scientific purposes.

|-
| 9:22
| '''pylab''' has

|-
| 9:23
| plot, bar, contour, boxplot, errorbar, log, polar, quiver, semilog

|-
| 9:32
| '''scipy (modules)'''has

|-
| 9:35
| fftpack, stats, linalg, ndimage, signal, optimize, integrate

|-
|9:46
| This brings us to the end of this tutorial.

|-
| 9:48
| In this tutorial, we have learnt to, 1. Define functions with default arguments.

|-
| 9:53
| 2. Call functions using keyword arguments.

|-
| 9:55
| 3. Use the range of functions available in the Python standard library and the Scientific Computing related packages.

|-
| 10:04
| Here are some self assessment questions for you to solve

|-
| 10:08
| 1. All arguments of a function cannot have default values. - True or False?

|-
| 10:14
| 2. The following is a valid function definition.

|-
| 10:17
| True or False?

|-
| 10:21
| def seperator within bracket count=40 comma char comma show=False colon
if show colon
print char star count
return char star count

|-
| 10:36
| 3. When calling a function, the arguments should always be in the order in which they are defined.

|-
| 10:45
| the arguments can be in any order.

|-
| 10:47
| '''only keyword arguments can be in any order, but should be called'''<br/> at the beginning.

|-
| 10:56
| only keyword arguments can be in any order, but should be called at the end.

|-
| 11:10
| And the answers,

|-
| 11:13
| 1.False.

|-
| 11:15
| All arguments of a Python function can have default values.

|-
| 11:21
| 2. False.

|-
| 11:23
| All parameters with default arguments should be defined at the end.

|-
| 11:27
| 3. When calling a function,only keyword arguments can be in any order, but should be called at the end.

|-
| 11:35
| Hope you have enjoyed this tutorial and found it useful.

|-
| 11:39
| Thank you!

|}

@@ Line 280: / Line 280: @@
 |-
 | 09:22
-| '''pylab''' has
+| '''pylab''' has plot, bar, contour, boxplot, errorbar, log, polar, quiver, semilog
-−
-|-
-| 09:23
-| plot, bar, contour, boxplot, errorbar, log, polar, quiver, semilog
 |-

@@ Line 10: / Line 10: @@
 | 00:06
 | At the end of this tutorial, you will be able to,
 Assign default values to arguments, when defining functions.
-# Assign default values to arguments, when defining functions.
+Define and call functions with keyword arguments.
-# Define and call functions with keyword arguments.
+Learn some of the built-in functions available in Python standard library and the scientific computing libraries.
-# Learn some of the built-in functions available in Python standard library and the scientific computing libraries.
 |-
@@ Line 37: / Line 36: @@
 |-
 |00:52
-|Type round within bracket 2.484 and hit enter.
+|Type round within bracket 2.484 and hit enter.Then type round  2.484 comma  2
 Then type round  2.484 comma  2
 |-
@@ Line 86: / Line 84: @@
 |-
 |02:54
-|So type in the terminal def welcome within bracket greet comma  name= within double quotes World colon (hit enter)
+|So type in the terminal def welcome within bracket greet comma  name= within double quotes World colon (hit enter) print greet comma  name (hit enter)
-                         print greet comma  name (hit enter)
 |-
@@ Line 135: / Line 132: @@
 |-
 |04:20
-|def welcome within bracket name= within double quotes World comma  greet colon (hit enter)
+|def welcome within bracket name= within double quotes World comma  greet colon (hit enter),  print greet comma  name (hit enter)
-    print greet comma  name (hit enter)
 |-
@@ Line 192: / Line 188: @@
 |-
 |05:51
-|Type def welcome within bracket greet= within double quotes Hello comma  name= in double quotes World colon
+|Type def welcome within bracket greet= within double quotes Hello comma  name= in double quotes World colon, print greet comma  name. After hitting enter type welcome()
-    print greet comma  name
-(After hitting enter type)
-    welcome()
 |-
@@ Line 311: / Line 304: @@
 |-
 | 09:53
-| 2. Call functions using keyword arguments.
+| Call functions using keyword arguments.
 |-
 | 09:55
-| 3. Use the range of functions available in the Python standard library and the Scientific Computing related packages.
+| Use the range of functions available in the Python standard library and the Scientific Computing related packages.
 |-
@@ Line 323: / Line 316: @@
 |-
 | 10:08
-| 1. All arguments of a function cannot have default values. - True or False?
+| All arguments of a function cannot have default values. - True or False?
 |-
 | 10:14
-| 2. The following is a valid function definition.
+| The following is a valid function definition.
 |-
@@ Line 335: / Line 328: @@
 |-
 | 10:21
-|  def separator within bracket count=40 comma  char comma  show=False colon
+|  def separator within bracket count=40 comma  char comma  show=False colon, if show colon print char  star  count   return char  star  count
-  if show colon
-  print char  star  count
    return char  star  count
 |-
 | 10:36
-| 3. When calling a function, the arguments should always be in the order in which they are defined.
+|  When calling a function, the arguments should always be in the order in which they are defined.
 |-
@@ Line 362: / Line 352: @@
 |-
 | 11:13
-| 1.False.
+| False.
 |-
@@ Line 370: / Line 360: @@
 |-
 | 11:21
-| 2. False.
+| False.
 |-
@@ Line 378: / Line 368: @@
 |-
 | 11:27
-| 3. When calling a function,only keyword arguments can be in any order, but should be called at the end.
+|When calling a function,only keyword arguments can be in any order, but should be called at the end.
 |-

@@ Line 20: / Line 20: @@
 |-
 | 0:32
-| Let us Start the ipython interpreter
+| Let us Start the ipython interpreter in command
 |-
@@ Line 37: / Line 37: @@
 |0:52
 |Type round within bracket 2.484 and hit enter.
-Then type round within bracket 2.484 comma  2
+Then type round  2.484 comma  2
 |-
@@ Line 61: / Line 61: @@
 |-
 | 1:52
-| plot within bracket x comma  y # plots with x vesus y using default line style. plot within bracket x comma  y comma  in single quote o # plots x versus y with circle markers.
+| plot within bracket x comma  y # plots with x versus y using default line style. plot within bracket x comma  y comma  in single quote o # plots x versus y with circle markers.
 |-
@@ Line 94: / Line 94: @@
 |-
 |3:25
-|So type welcome within bracket  within double quotes Hi comma   within double quotes Guido
+|So type welcome  and in bracket  within double quotes Hi comma   within double quotes Guido
 |-
@@ Line 191: / Line 191: @@
 |-
 |5:51
-|Type def welcome within bracket greet= within double quotes Hello comma  name= within double quotes World colon
+|Type def welcome within bracket greet= within double quotes Hello comma  name= in double quotes World colon
      print greet comma  name
 (After hitting enter type)
@@ Line 214: / Line 214: @@
 |-
 | 6:38
-| Instead, you can use the name of the argument to pass it a value.
+| Instead, you need the name of the argument to pass it a value.
 |-
@@ Line 234: / Line 234: @@
 |-
 |7:14
-|So in terminal type welcome()
+|So type in terminal type welcome()
-welcome within bracket  within double quotes Hello comma   within double quotes James
+welcome within bracket  within double quotes Hello comma  double quotes James
 welcome within bracket  within double quotes Hi comma  name= within double quotes Guido
@@ Line 250: / Line 250: @@
 |-
 | 7:48
-| If we type in the terminal welcome within bracket name= within double quotes Guido comma  greet= within double quotes Hey exclamation
+| If we type on the terminal welcome within bracket name= within double quotes Guido comma  greet= within double quotes Hey exclamation
 |-
@@ Line 353: / Line 353: @@
 |-
 | 10:56
-|  only keyword arguments can be in any order, but should be called at the end.
+|  only keyword arguments can be in any order, and should be called at the end.
 |-
 | 11:10
-| And the answers,
+| So now we can look at the answers,
 |-

@@ Line 28: / Line 28: @@
 |-
 | 0:43
-| Let's use the <tt>round</tt> function as an example to understand what a default value of an argument means.
+| Let's use the  round  function as an example to understand what a default value of an argument means.
 |-
@@ Line 41: / Line 41: @@
 |-
 | 1:10
-| Both the first expression and the second are calls to the <tt>round</tt> function, but the first calls it with only one argument and the second calls it with two arguments.
+| Both the first expression and the second are calls to the round  function, but the first calls it with only one argument and the second calls it with two arguments.
 |-
@@ Line 90: / Line 90: @@
 |-
 | 3:18
-| Let us first call the function with two arguments, one for <tt>greet</tt> and other for <tt>name</tt>.
+| Let us first call the function with two arguments, one for  greet  and other for  name .
 |-
@@ Line 110: / Line 110: @@
 |-
 | 3:53
-| "Hello" is treated as the <tt>greet</tt> and we get "Hello World" as the output.
+| "Hello" is treated as the greet  and we get "Hello World" as the output.
 |-
 | 3:59
-| "World" is the default value for the argument <tt>name</tt>.
+| "World" is the default value for the argument  name .
 |-
@@ Line 122: / Line 122: @@
 |-
 | 4:07
-| '''Redefine the function <tt>welcome</tt>, by interchanging it's''' arguments.
+| '''Redefine the function  welcome , by interchanging it's''' arguments.
 |-
 | 4:11
-| Place the <tt>name</tt> argument with it's default value of "World" before the <tt>greet</tt> argument.
+| Place the name  argument with it's default value of "World" before the  greet  argument.
 |-
@@ Line 139: / Line 139: @@
 |-
 | 4:36
-| We get an error that reads <tt>SyntaxError: non-default argument follows default argument</tt>.Then ipython control line one.
+| We get an error that reads SyntaxError: non-default argument follows default argument .Then ipython control line one.
 |-
@@ Line 151: / Line 151: @@
 |-
 | 4:58
-| '''See the definition of linspace using <tt>question mark</tt> and make a note of all''' the arguments with default values are towards the end.
+| '''See the definition of linspace using  question mark  and make a note of all''' the arguments with default values are towards the end.
 |-
@@ Line 163: / Line 163: @@
 |-
 | 5:17
-| <nowiki>As we go on hitting the enter key, we the the number of arguments this command has.
+| As we go on hitting the enter key, we the the number of arguments this command has.
 |-
 | 5:26
-| Please read the content on your terminal. <pause></nowiki>
+| Please read the content on your terminal.
 |-
@@ Line 175: / Line 175: @@
 |-
 | 5:35
-| '''Redefine the function <tt>welcome</tt> with a default value of'''
+| '''Redefine the function  welcome  with a default value of'''
 |-
 | 5:41
-| "Hello" to the <tt>greet</tt> argument.
+| "Hello" to the  greet  argument.
 |-
@@ Line 198: / Line 198: @@
 |-
 | 6:17
-| As we can see, we get the output as <tt>Hello World</tt>.
+| As we can see, we get the output as  Hello World .
 |-
@@ Line 222: / Line 222: @@
 |-
 | 6:52
-| <tt>loc</tt>, <tt>linewidth</tt>, <tt>xy</tt> and <tt>labels</tt> are being called with keyword arguments.
+| loc , linewidth ,  xy  and  labels<  are being called with keyword arguments.
 |-
 | 7:00
-| Let us try and understand this better using the <tt>welcome</tt> function that we have been using all along.
+| Let us try and understand this better using the  welcome  function that we have been using all along.
 |-
@@ Line 246: / Line 246: @@
 |-
 | 7:42
-| So, "Hi" is the value of the argument <tt>greet</tt> and name is passed the value "Guido".
+| So, "Hi" is the value of the argument greet  and name is passed the value "Guido".
 |-
@@ Line 262: / Line 262: @@
 |-
 | 8:17
-| This call returns an error that reads, <tt>non-keyword arg after keyword arg</tt>. Python expects all the keyword to be present towards the end.
+| This call returns an error that reads, non-keyword arg after keyword arg . Python expects all the keyword to be present towards the end.
 |-
 | 8:30
-| That brings us to the end of what we wanted to learn about <tt>keyword</tt> arguments.
+| That brings us to the end of what we wanted to learn about  keyword  arguments.
 |-
@@ Line 282: / Line 282: @@
 |-
 | 9:11
-| Apart from the standard library there are other libraries like <tt>pylab</tt>, <tt>scipy</tt>, etc which have a huge collection of functions for scientific purposes.
+| Apart from the standard library there are other libraries like  pylab ,  scipy , etc which have a huge collection of functions for scientific purposes.
 |-
@@ Line 334: / Line 334: @@
 |-
 | 10:21
-|  def seperator within bracket count=40 comma  char comma  show=False colon
+|  def separator within bracket count=40 comma  char comma  show=False colon
    if show colon
    print char  star  count
@@ Line 349: / Line 349: @@
 |-
 | 10:47
-|  '''only keyword arguments can be in any order, but should be called'''<br/> at the beginning.
+|  '''only keyword arguments can be in any order, but should be called''' at the beginning.
 |-