Python/C2/loading-data-from-files/English-timed - Revision history

PoojaMoolya at 05:14, 27 March 2017

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PoojaMoolya at 12:24, 20 February 2017

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PoojaMoolya at 05:21, 7 August 2014

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Gaurav at 07:02, 10 July 2014

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Sneha at 05:58, 11 March 2013

2013-03-11T05:58:40Z

Sneha at 11:43, 8 March 2013

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Sneha at 11:39, 8 March 2013

2013-03-08T11:39:50Z

Minal: Created page with '{| border=1 !Visual Cue !Narration |- | 0:01 | Hello Friends and Welcome to this tutorial on "loading data from files". |- | 0:06 | At the end of this tutorial, you will be able…'

2013-01-02T10:51:53Z

Created page with '{| border=1 !Visual Cue !Narration |- | 0:01 | Hello Friends and Welcome to this tutorial on "loading data from files". |- | 0:06 | At the end of this tutorial, you will be able…'

New page

{| border=1
!Visual Cue
!Narration
|-
| 0:01
| Hello Friends and Welcome to this tutorial on "loading data from files".

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

# Read data from files, containing a single column of data
# Read multiple columns of data, separated by spaces or other delimiters.

|-
| 0:19
| Let us switch to the terminal and start IPython, using ipython hypen pylab

|-
| 0:33
| Now, Let us begin with reading the file primes.txt, which contains a list of prime numbers listed in a column, using the loadtxt command.

|-
| 0:45
|Please make sure that you provide the correct path of the file, 'primes.txt'.

|-
| 0:50
|The file, in our case, is present in <tt>slash home slash fossee slash primes.txt</tt>.

|-
| 0:59
| Otherwise we can use the <tt>cat</tt> command to locate the file and read the contents of it.

|-
|1:05
|So type cat slash home slash fossee slash primes.txt

|-
| 1:15
| Now let us read this list into the variable <tt>primes</tt>.

|-
|1:20
|So type primes = loadtxt within bracket in single quotes slash home slash fossee slash primes.txt

|-
| 1:41
| <tt>primes</tt> is now a sequence of prime numbers, that was listed in the file,``primes.txt``.

|-
| 1:49
|We now type, <tt>print space primes</tt> to see the sequence printed.

|-
| 2:00
| We observe that all the numbers end with a period.

|-
| 2:04
|This is so, because these numbers are actually read as <tt>floats</tt>.

|-
| 2:10
| Now, let us use the <tt>loadtxt</tt> command to read a file <tt>pendulum.txt</tt> that contains two columns of data.

|-
| 2:19
| This file contains the length of the pendulum in the first column and the corresponding time period in the second.

|-
| 2:26
| Note that here <tt>loadtxt</tt> needs both the columns to have equal number of rows.

|-
| 2:31
|We use the <tt>cat</tt> command to view the contents of this file.

|-
| 2:36
| So type cat slash home slash fossee slash pendulum.txt

|-
| 2:50
| Let us, now, read the data into the variable <tt>pend</tt>.

|-
| 2:55
|Again, it is assumed that the file is in <tt>slash home slash fossee</tt>

|-
| 3:02
|So type pend = loadtxt within bracket in single quote slash home slash fossee slash pendulum.txt

|-
| 3:21
| Let us now print the variable <tt>pend</tt> and see what it contains.

|-
|3:26
|So type print pend

|-
| 3:31
| Notice that <tt>pend</tt> is not a simple sequence like <tt>primes</tt>.

|-
| 3:35
|It has two sequences, containing both the columns of the data file.

|-
| 3:40
| Let us use an additional argument of the <tt>loadtxt</tt> command, to read it into two separate, simple sequences.

|-
|3:50
|So type L, T space = space loadtxt within bracket single quoteslash home slash fossee slash pendulum.txt comma unpack=True

|-
| 4:23
| Let us now, print the variables L and T, to see what they contain.

|-
|4:29
|So type print space L
print space T

|-
| 4:39
| Notice, that L and T now contain the first and second columns of data from the data file, <tt>pendulum.txt</tt>, and they are both simple sequences.

|-
| 4:50
| <tt>unpack=True</tt> has given us the two columns into two separate sequences instead of one complex sequence.

|-
| 5:00
| Till now, we have learnt the basic use of the <tt>loadtxt</tt> command.

|-
| 5:05
| Let us try an example.

|-
| 5:07
|Pause the video here, try out the following exercise and resume the video.

|-
| 5:12
|Read the file <tt>pendulum underscore semicolon.txt</tt> which contains the same data as <tt>pendulum.txt</tt>, but the columns are separated by semi-colons instead of spaces.

|-
| 5:27
| Use the IPython help to see how to do this.

|-
|5:34
|Switch back to the terminal

L comma T = loadtxt within bracket in single quote slash home slash fossee slash pendulum underscore semicolon.txt comma unpack=True comma
delimiter=semi-colon within single quote

|-
|6:54
|Okay then type print L

|-
|6:40
|print T

|-
| 6:45
| This brings us to the end of this tutorial.

|-
| 6:48
| In this tutorial, we have learnt to,

|-
| 6:51
| 1. To Read data from files, containing a single column of data using the <tt>loadtxt</tt> command.

|-
| 6:58
| 2. To Read multiple columns of data, separated by spaces or other delimiters.

|-
| 7:04
| Here are some self assessment questions for you to solve
1. <tt>loadtxt</tt> can read data from a file with one column only. True or False?

|-
| 7:18
| 2. Given a file <tt>data.txt</tt> with three columns of data separated by spaces, read it into 3 separate simple sequences.

|-
| 7:29
| 3. Given a file <tt>data.txt</tt> with three columns of data separated by ":", read it into 3 separate simple sequences.

|-
| 7:45
| And the answers,1. False.

|-
| 7:50
| <tt>loadtxt</tt> command can read data from files having both single columns as well as multiple columns.

|-
| 7:58
| 2. A file with three columns of data separated by spaces to be read into 3 separate sequences, we use the loadtxt command as, x = loadtxt within bracket in double quotes data.txt comma unpack=True

|-
| 8:19
| 3. If a file with three columns of data separated by delimiters,we read it into three separate sequences by using an additional argument of delimiter in the loadtxt command
x = loadtxt within bracket in double quotes data.txt comma unpack=True comma delimiter=in double quotes colon)

|-
| 8:51
| Hope you have enjoyed this tutorial and found it useful.

|-
| 8:55
| Thank you!

@@ Line 9: / Line 9: @@
 |-
 | 00:06
-| At the end of this tutorial, you will be able to,
+| At the end of this tutorial, you will be able to, Read data from files, containing a single column of data
 Read data from files, containing a single column of data
 Read multiple columns of data, separated by spaces or other delimiters.
@@ Line 156: / Line 156: @@
 |05:34
 |Switch back to the terminal
-L comma T = loadtxt within bracket in single quote slash home slash fossee slash pendulum underscore semicolon.txt comma unpack=True comma delimiter=semi-colon within single quote
+L comma T = loadtxt within bracket in single quote slash home slash fossee slash pendulum underscore semicolon.txt then comma unpack=True comma delimiter=semi-colon within single quote
 |-
-|06:54
+|06:33
 |Okay then type print L

@@ Line 10: / Line 10: @@
 | 00:06
 | At the end of this tutorial, you will be able to,
 Read data from files, containing a single column of data
-# Read data from files, containing a single column of data
+Read multiple columns of data, separated by spaces or other delimiters.
-# Read multiple columns of data, separated by spaces or other delimiters.
 |-
@@ Line 124: / Line 123: @@
 |-
 |04:29
-|So type print space L
+|So type print space L, print  space T
 print  space T
 |-
@@ Line 158: / Line 156: @@
 |05:34
 |Switch back to the terminal
 L comma T = loadtxt within bracket in single quote slash home slash fossee slash pendulum underscore semicolon.txt comma unpack=True comma delimiter=semi-colon within single quote
 L comma T = loadtxt within bracket in single quote slash home slash fossee slash pendulum underscore semicolon.txt comma unpack=True comma
-               delimiter=semi-colon within single quote
 |-

@@ Line 221: / Line 221: @@
 |-
-| 8:55
+| 08:55
 | Thank you!

@@ Line 27: / Line 27: @@
 |-
 | 0:50
-|The file, in our case, is present in  slash home slash fossee slash primes.txt.
+|The file, in our case, is presented in  slash home slash fossee slash primes.txt.
 |-
@@ Line 51: / Line 51: @@
 |-
 | 1:49
-|We now type,print space primes to see the sequence printed.
+|We now type primes,print  primes to see the sequence printed so type print space primes.
 |-
@@ Line 75: / Line 75: @@
 |-
 | 2:31
-|We use the  cat  command to view the contents of this file.
+|We can use the  cat  command to view the contents of this file.
 |-
@@ Line 200: / Line 200: @@
 |-
 | 7:45
-| And the answers,1. False.
+| And now the answers,1. False.
 |-
@@ Line 213: / Line 213: @@
 | 8:19
 | 3. If a file with three columns of data separated by delimiters,we read it into three separate sequences by using an additional argument of delimiter in the loadtxt command
-x = loadtxt within bracket in double quotes data.txt comma unpack=True comma delimiter=in double quotes colon)
+x = loadtxt within bracket in double quotes data.txt comma unpack=True comma delimiter=in double quotes semicolon)
 |-

@@ Line 111: / Line 111: @@
 |-
 | 3:40
-| Let us use an additional argument of the  loadtxt command, to read it into two separate, simple sequences.
+| Let us use an additional argument of the  load txt command, to read it into two separate, simple sequences.
 |-
 |3:50
-|So type L, T space = space loadtxt within bracket single quoteslash home slash fossee slash pendulum.txt comma unpack=True
+|So type L, T space = space load txt within bracket single quote slash home slash fossee slash pendulum.txt comma unpack=True
 |-
@@ Line 136: / Line 136: @@
 |-
 |  5:00
-| Till now, we have learnt the basic use of the loadtxt command.
+| Till now, we have learnt the basic use of the load txt command.
 |-
@@ Line 179: / Line 179: @@
 |-
 | 6:51
-| 1. To Read data from files, containing a single column of data using the <tt>loadtxt</tt> command.
+| 1. To Read data from files, containing a single column of data using the loadtxt command.
 |-

@@ Line 27: / Line 27: @@
 |-
 | 0:50
-|The file, in our case, is present in <tt>slash home slash fossee slash primes.txt</tt>.
+|The file, in our case, is present in  slash home slash fossee slash primes.txt.
 |-
 |  0:59
-| Otherwise we can use the <tt>cat</tt> command to locate the file and read the contents of it.
+| Otherwise we can use the cat command to locate the file and read the contents of it.
 |-
@@ Line 39: / Line 39: @@
 |-
 | 1:15
-| Now let us read this list into the variable <tt>primes</tt>.
+| Now let us read this list into the variable primes.
 |-
@@ Line 47: / Line 47: @@
 |-
 | 1:41
-| <tt>primes</tt> is now a sequence of prime numbers, that was listed in the file,``primes.txt``.
+|primes  is now a sequence of prime numbers, that was listed in the file,``primes.txt``.
 |-
 | 1:49
-|We now type, <tt>print space primes</tt> to see the sequence printed.
+|We now type,print space primes to see the sequence printed.
 |-
@@ Line 59: / Line 59: @@
 |-
 | 2:04
-|This is so, because these numbers are actually read as <tt>floats</tt>.
+|This is so, because these numbers are actually read as floats
 |-
 | 2:10
-| Now, let us use the <tt>loadtxt</tt> command to read a file <tt>pendulum.txt</tt> that contains two columns of data.
+| Now, let us use the loadtxt command to read a file pendulum.txt that contains two columns of data.
 |-
@@ Line 71: / Line 71: @@
 |-
 | 2:26
-| Note that here <tt>loadtxt</tt> needs both the columns to have equal number of rows.
+| Note that here  loadtxt  needs both the columns to have equal number of rows.
 |-
 | 2:31
-|We use the <tt>cat</tt> command to view the contents of this file.
+|We use the  cat  command to view the contents of this file.
 |-
@@ Line 83: / Line 83: @@
 |-
 | 2:50
-| Let us, now, read the data into the variable <tt>pend</tt>.
+| Let us, now, read the data into the variable pend.
 |-
 | 2:55
-|Again, it is assumed that the file is in <tt>slash home slash fossee</tt>
+|Again, it is assumed that the file is in  slash home slash fossee
 |-
@@ Line 95: / Line 95: @@
 |-
 |  3:21
-| Let us now print the variable <tt>pend</tt> and see what it contains.
+| Let us now print the variable  pend  and see what it contains.
 |-
@@ Line 103: / Line 103: @@
 |-
 |  3:31
-| Notice that <tt>pend</tt> is not a simple sequence like <tt>primes</tt>.
+| Notice that  pend  is not a simple sequence like  primes .
 |-
@@ Line 111: / Line 111: @@
 |-
 | 3:40
-| Let us use an additional argument of the <tt>loadtxt</tt> command, to read it into two separate, simple sequences.
+| Let us use an additional argument of the  loadtxt command, to read it into two separate, simple sequences.
 |-
@@ Line 128: / Line 128: @@
 |-
 | 4:39
-| Notice, that L and T now contain the first and second columns of data from the data file, <tt>pendulum.txt</tt>, and they are both simple sequences.
+| Notice, that L and T now contain the first and second columns of data from the data file, pendulum.txt, and they are both simple sequences.
 |-
 | 4:50
-| <tt>unpack=True</tt> has given us the two columns into two separate sequences instead of one complex sequence.
+|unpack=True has given us the two columns into two separate sequences instead of one complex sequence.
 |-
 |  5:00
-| Till now, we have learnt the basic use of the <tt>loadtxt</tt> command.
+| Till now, we have learnt the basic use of the loadtxt command.
 |-
@@ Line 148: / Line 148: @@
 |-
 | 5:12
-|Read the file <tt>pendulum underscore semicolon.txt</tt> which contains the same data as <tt>pendulum.txt</tt>, but the columns are separated by semi-colons instead of spaces.
+|Read the file pendulum underscore semicolon.txt which contains the same data as pendulum.txt, but the columns are separated by semi-colons instead of spaces.
 |-
@@ Line 188: / Line 188: @@
 | 7:04
 | Here are some self assessment questions for you to solve
-. <tt>loadtxt</tt> can read data from a file with one column only. True or False?
+. loadtxt can read data from a file with one column only. True or False?
 |-
 | 7:18
-| 2. Given a file <tt>data.txt</tt> with three columns of data separated by spaces, read it into 3 separate simple sequences.
+| 2. Given a file data.txt with three columns of data separated by spaces, read it into 3 separate simple sequences.
 |-
 | 7:29
-| 3. Given a file <tt>data.txt</tt> with three columns of data separated by ":", read it into 3 separate simple sequences.
+| 3. Given a file data.txt with three columns of data separated by ":", read it into 3 separate simple sequences.
 |-
@@ Line 204: / Line 204: @@
 |-
 | 7:50
-| <tt>loadtxt</tt> command can read data from files having both single columns as well as multiple columns.
+|loadtxt command can read data from files having both single columns as well as multiple columns.
 |-