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authorNishanth Amuluru2010-09-23 11:54:36 +0530
committerNishanth Amuluru2010-09-23 11:54:36 +0530
commitd0b50b68312d7be4a35cf2a58bfbcb2394282e2b (patch)
tree5e6990efb302c6567220fb93a936e9da213f66d7
parent044912faff8be00b894c3951451a779013ce6495 (diff)
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reviewed loading_data_from_files
-rw-r--r--loading-data-from-files.rst30
-rw-r--r--progress.org2
2 files changed, 27 insertions, 5 deletions
diff --git a/loading-data-from-files.rst b/loading-data-from-files.rst
index 04d6505..5196619 100644
--- a/loading-data-from-files.rst
+++ b/loading-data-from-files.rst
@@ -12,8 +12,10 @@ plotting them, against another sequence of points. But, this is not
what we do most often. We often require to plot points obtained from
experimental observations.
-#[punch: the initial part of the paragraph may be removed, to make
-this a more generic LO?]
+.. #[punch: the initial part of the paragraph may be removed, to make
+ this a more generic LO?]
+
+.. #[Nishanth]: The paragraph can be removed.
In this tutorial we shall learn to read data from files and save it
into sequences that can later be used to plot.
@@ -24,6 +26,9 @@ We shall use the ``loadtxt`` command to load data from files. We will
be looking at how to get multiple columns of data into multiple
sequences.
+.. #[Nishanth]: can be "How to read a file with multiple columns of
+ data and load each column of data into a sequence."
+
{{{ switch back to the terminal }}}
As usual, let us start IPython, using
@@ -35,7 +40,7 @@ Now, Let us begin with reading the file primes.txt, which contains
just a list of primes listed in a column, using the loadtxt command.
The file, in our case, is present in ``/home/fossee/primes.txt``.
-#[punch: do we need a slide for showing the path?]
+.. #[punch: do we need a slide for showing the path?]
We use the ``cat`` command to see the contents of this file.
@@ -44,6 +49,10 @@ to do it] ::
cat /home/fossee/primes.txt
+.. #[Nishanth]: A problem for windows users.
+ Should we simply open the file and show them the data
+ so that we can be fine with GNU/Linux ;) and windows?
+
Now let us read this list into the variable ``primes``.
::
@@ -71,6 +80,12 @@ This is how we look at the contents of the file, ``pendulum.txt``
cat /home/fossee/pendulum.txt
+.. #[Nishanth]: The first column is L values and second is T values
+ from a simle pelculum experiment.
+ Since you are using the variable names later in the
+ script.
+ Not necessary but can be included also.
+
Let us, now, read the data into the variable ``pend``. Again, it is
assumed that the file is in ``/home/fossee/``
::
@@ -90,12 +105,17 @@ two separate, simple sequences.
L, T = loadtxt('/home/fossee/pendulum.txt', unpack=True)
+.. #[Nishanth]: It has a sequence of items in which each item contains
+ two values. first is l and second is t
+
Let us now, print the variables L and T, to see what they contain.
::
print L
print T
+.. #[Nishanth]: Stress on ``unpack=True`` ??
+
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.
@@ -115,12 +135,14 @@ finished, resume the video to look at the solution.
{{{ switch back to the terminal }}}
::
- L, T = loadtxt('/home/fossee/pendulum.txt', unpack``True, delimiter``';')
+ L, T = loadtxt('/home/fossee/pendulum.txt', unpack=True, delimiter=';')
print L
print T
+.. #[Nishanth]: L, T = loadtxt('/home/fossee/pendulum_semicolon.txt', ...)
+
This brings us to the end of this tutorial.
{{{ show the summary slide }}}
diff --git a/progress.org b/progress.org
index 4142673..4d2574b 100644
--- a/progress.org
+++ b/progress.org
@@ -8,7 +8,7 @@
| 1.7 LO: | additional features of IPython | 2 | Nishanth | Amit (Pending) | Madhu (Pending) |
| 1.8 LO: | module level assessment | 3 | Madhu | | |
|---------+----------------------------------------+-------+----------+---------------------+---------------------|
-| 2.2 LO: | loading data from files | 3 | Punch | | |
+| 2.2 LO: | loading data from files | 3 | Punch | Nishanth (Done) | Anoop (Pending) |
| 2.3 LO: | plotting the data | 3 | Amit | Anoop (Pending) | Punch (Pending) |
| 2.4 LO: | other types of plots | 3 | Anoop | | |
| 2.5 LO: | module level assessment | 3 | Nishanth | | |