This should get you started:

    set datafile separator &quot;,&quot;
    plot &#39;infile&#39; using 0:1

You can also plot to a png file using gnuplot (which is free):

terminal commands

    gnuplot&gt; set title &#39;&lt;title&gt;&#39;
    gnuplot&gt; set ylabel &#39;&lt;yLabel&gt;&#39;
    gnuplot&gt; set xlabel &#39;&lt;xLabel&gt;&#39;
    gnuplot&gt; set grid
    gnuplot&gt; set term png
    gnuplot&gt; set output &#39;&lt;Output file name&gt;.png&#39;
    gnuplot&gt; plot &#39;&lt;fromfile.csv&gt;&#39;

*note: you always need to give the right extension (.png here) at `set output`*

Then it is also possible that the ouput is not lines, because your data is not continues. To fix this simply change the &#39;plot&#39; line to:

    plot &#39;&lt;Fromfile.csv&gt;&#39; with line lt -1 lw 2

More line editing options (dashes and line color ect.) at:
http://gnuplot.sourceforge.net/demo_canvas/dashcolor.html

 * gnuplot is available in most linux distros via the package manager (e.g. on an apt based distro, run `apt-get install gnuplot`)
 * gnuplot is available in windows via Cygwin
 * gnuplot is available on macOS via [homebrew][1] (run `brew install gnuplot`)


  [1]: https://brew.sh

One of my favorite aspects of using the `ggplot2` library in R is the ability to easily specify aesthetics. I can quickly make a scatterplot and apply color associated with a specific column and I would love to be able to do this with python/pandas/matplotlib.  I&#39;m wondering if there are there any convenience functions that people use to map colors to values using pandas dataframes and Matplotlib?



    ##ggplot scatterplot example with R dataframe, `df`, colored by col3
    ggplot(data = df, aes(x=col1, y=col2, color=col3)) + geom_point()
    
    ##ideal situation with pandas dataframe, &#39;df&#39;, where colors are chosen by col3
    df.plot(x=col1,y=col2,color=col3)




EDIT:
Thank you for your responses but I want to include a sample dataframe to clarify what I am asking. Two columns contain numerical data and the third is a categorical variable. The script I am thinking of will assign colors based on this value.


```python
np.random.seed(250)
df = pd.DataFrame({&#39;Height&#39;: np.append(np.random.normal(6, 0.25, size=5), np.random.normal(5.4, 0.25, size=5)),
                   &#39;Weight&#39;: np.append(np.random.normal(180, 20, size=5), np.random.normal(140, 20, size=5)),
                   &#39;Gender&#39;: [&quot;Male&quot;,&quot;Male&quot;,&quot;Male&quot;,&quot;Male&quot;,&quot;Male&quot;,
                              &quot;Female&quot;,&quot;Female&quot;,&quot;Female&quot;,&quot;Female&quot;,&quot;Female&quot;]})

     Height      Weight  Gender
0  5.824970  159.210508    Male
1  5.780403  180.294943    Male
2  6.318295  199.142201    Male
3  5.617211  157.813278    Male
4  6.340892  191.849944    Male
5  5.625131  139.588467  Female
6  4.950479  146.711220  Female
7  5.617245  121.571890  Female
8  5.556821  141.536028  Female
9  5.714171  134.396203  Female
```

 



Color by Column Values in Matplotlib

I am using this to login the user in:

    def login_backend(request):
        if request.method == &#39;POST&#39;:
            username = request.POST[&#39;username&#39;]
            password = request.POST[&#39;password&#39;]
            user = authenticate(username=username, password=password)
            if user is not None:
                login(request, user)
                request.session.set_expiry(300)
                return HttpResponseRedirect(&#39;/overview/&#39;)
            else:
                return HttpResponseRedirect(&#39;/login_backend/&#39;)
        else:
            return render_to_response(&#39;login_backend.html&#39;, context_instance=RequestContext(request))

I want session to expire after 5mins thus I added `request.session.set_expiry(300)` in the view above. But the session is never expiring. What am I doing wrong?


How to expire Django session in 5minutes?

I have a csv file which has 5 entries on every row. Every entry is whether a network packet is triggered or not. The last entry in every row is the size of packet. Every row = time elapsed in ms.

e.g. row 

    1 , 0 , 1 , 2 , 117

How do I plot a graph for e.g. where x axis is the row number and y is the value for e.g. 1st entry in every row?



Plotting using a CSV file

I have a csv file which has 5 entries on every row. Every entry is whether a network packet is triggered or not. The last entry in every row is the size of packet. Every row = time elapsed in ms.
e.g. row
<pre><code class="hljs">1 , 0 , 1 , 2 , 117
</code></pre>
How do I plot a graph for e.g. where x axis is the row number and y is the value for e.g. 1st entry in every row?

I know there are lot of questions of this nature but I need to do this using JavaScript. I am using `Dojo 1.8` and have all the attribute info in array, which looks like this:

    [[&quot;name1&quot;, &quot;city_name1&quot;, ...][&quot;name2&quot;, &quot;city_name2&quot;, ...]]

Any idea how I can export this to `CSV` on the client side?

How to export JavaScript array info to csv (on client side)?

Is there a built-in way to use `read_csv` to read only the first `n` lines of a file without knowing the length of the lines ahead of time? I have a large file that takes a long time to read, and occasionally only want to use the first, say, 20 lines to get a sample of it (and prefer not to load the full thing and take the head of it).

If I knew the total number of lines I could do something like `footer_lines = total_lines - n` and pass this to the `skipfooter` keyword arg. My current solution is to manually grab the first `n` lines with python and StringIO it to pandas:

    import pandas as pd
    from StringIO import StringIO

    n = 20
    with open(&#39;big_file.csv&#39;, &#39;r&#39;) as f:
        head = &#39;&#39;.join(f.readlines(n))

    df = pd.read_csv(StringIO(head))

It&#39;s not that bad, but is there a more concise, &#39;pandasic&#39; (?) way to do it with keywords or something?

Way to read first few lines for pandas dataframe

I have a csv file which isn&#39;t coming in correctly with ``pandas.read_csv`` when I  filter the columns with ``usecols`` and use multiple indexes.   
&lt;!-- language: lang-py --&gt;

    import pandas as pd
    csv = r&quot;&quot;&quot;dummy,date,loc,x
       bar,20090101,a,1
       bar,20090102,a,3
       bar,20090103,a,5
       bar,20090101,b,1
       bar,20090102,b,3
       bar,20090103,b,5&quot;&quot;&quot;

    f = open(&#39;foo.csv&#39;, &#39;w&#39;)
    f.write(csv)
    f.close()
    
    df1 = pd.read_csv(&#39;foo.csv&#39;,
            header=0,
            names=[&quot;dummy&quot;, &quot;date&quot;, &quot;loc&quot;, &quot;x&quot;], 
            index_col=[&quot;date&quot;, &quot;loc&quot;], 
            usecols=[&quot;dummy&quot;, &quot;date&quot;, &quot;loc&quot;, &quot;x&quot;],
            parse_dates=[&quot;date&quot;])
    print df1
    
    # Ignore the dummy columns
    df2 = pd.read_csv(&#39;foo.csv&#39;, 
            index_col=[&quot;date&quot;, &quot;loc&quot;], 
            usecols=[&quot;date&quot;, &quot;loc&quot;, &quot;x&quot;], # &lt;----------- Changed
            parse_dates=[&quot;date&quot;],
            header=0,
            names=[&quot;dummy&quot;, &quot;date&quot;, &quot;loc&quot;, &quot;x&quot;])
    print df2

I expect that df1 and df2 should be the same except for the missing dummy column, but the columns come in mislabeled.  Also the date is getting parsed as a date.  

    In [118]: %run test.py
                   dummy  x
    date       loc
    2009-01-01 a     bar  1
    2009-01-02 a     bar  3
    2009-01-03 a     bar  5
    2009-01-01 b     bar  1
    2009-01-02 b     bar  3
    2009-01-03 b     bar  5
                  date
    date loc
    a    1    20090101
         3    20090102
         5    20090103
    b    1    20090101
         3    20090102
         5    20090103

Using column numbers instead of names give me the same problem.  I can workaround the issue by dropping the dummy column after the read_csv step, but I&#39;m trying to understand what is going wrong.  I&#39;m using pandas 0.10.1.

edit: fixed bad header usage.


pandas read_csv and filter columns with usecols

I need to create a data frame by reading in data from a file, using `read_csv` method. However, the separators are not very regular: some columns are separated by tabs (`\t`), other are separated by spaces. Moreover, some columns can be separated by 2 or 3 or more spaces or even by a combination of spaces and tabs (for example 3 spaces, two tabs and then 1 space).

Is there a way to tell pandas to treat these files properly?

By the way, I do not have this problem if I use Python. I use:

    for line in file(file_name):
       fld = line.split()

And it works perfect. It does not care if there are 2 or 3 spaces between the fields. Even combinations of spaces and tabs do not cause any problem. Can pandas do the same?

How to make separator in pandas read_csv more flexible wrt whitespace, for irregular separators?

I have a script reading in a csv file with very huge fields:

    # example from http://docs.python.org/3.3/library/csv.html?highlight=csv%20dictreader#examples
    import csv
    with open(&#39;some.csv&#39;, newline=&#39;&#39;) as f:
        reader = csv.reader(f)
        for row in reader:
            print(row)

However, this throws the following error on some csv files:

    _csv.Error: field larger than field limit (131072)
    
How can I analyze csv files with huge fields? Skipping the lines with huge fields is not an option as the data needs to be analyzed in subsequent steps.

_csv.Error: field larger than field limit (131072)

At https://github.com/yourusername/yourreponame/graphs you can find some nice graphs showing commits over time. However the information is only for the master branch.

How do I see the same information for a branch other than master, or see a graphs taking account commits across all branches?

If this is not possible, how can I at least see how many line of code have been committed under a particular branch via the GitHub web GUI?

Is any of this possible?

How to view GitHub Contributors Graph for branches other than master?

I&#39;m using pyplot.bar but I&#39;m plotting so many points that the color of the bars is always black.  This is because the borders of the bars are black and there are so many of them that they are all squished together so that all you see is the borders (black).  Is there a way to remove the bar borders so that I can see the intended color?

matplotlib bar graph black - how do I remove bar borders

What is the main difference between dynamic programming and greedy approach in terms of usage?

As far as I understood, the _greedy_ approach sometimes gives an optimal solution; in other cases, the _dynamic programming_ approach gives an optimal solution. 

Are there any particular conditions which must be met in order to use one approach (or the other) to obtain an optimal solution?

What is the difference between dynamic programming and greedy approach?

Can anybody please provide or point out to a good comparison between Neo4j and Titan? 
One thing i can see is in terms of scale - Titan is scaleout and requires an underlying scalable datastore like cassandra. Neo4j is only for HA and has its own embedded database. Any other pros and cons? Any specific usecases. (Is Titan being used anywhere currently?)
 
I also have the following link: http://architects.dzone.com/articles/16-graph-databases-compared that gives a objective compare for graph databases but not much on pros and cons between Neo4j and Titan.


anybody tried neo4j vs titan - pros and cons

I&#39;ve considered creating a Vertices table and an Edges table but would building graphs in memory and traversing sub-graphs require a large number of lookups? I&#39;d like to avoid excessive database reads. Is there any other way of persisting a graph? 

Side note: I&#39;ve heard of Neo4j but my question is really how to conceptually represent a graph in a standard database. I am open to some NoSQL solutions like mongodb though.

How to persist a graph data structure in a relational database?

Is there any way to iteratively retrieve data from multiple files and plot them on the same graph in gnuplot. Suppose I have files like data1.txt, data2.txt......data1000.txt; each having the same number of columns. Now I could write something like-

    plot &quot;data1.txt&quot; using 1:2 title &quot;Flow 1&quot;, \
         &quot;data2.txt&quot; using 1:2 title &quot;Flow 2&quot;, \
          .
          .
          .
         &quot;data1000.txt&quot;  using 1:2 title &quot;Flow 6&quot;

But this would be really inconvenient. I was wondering whether there is a way to loop through the **plot** part in gnuplot.


Loop structure inside gnuplot?

How to change point size and shape and color in gnuplot.

    plot &quot;./points.dat&quot; using 1:2 title with dots

I am using above command to plot graph ,but it shows very small size points.

I tried to use command 

    set pointsize 20

but still point size is same.

How to change dot size in gnuplot

I have a quick question regarding dates and times in x-axis in GNUPLOT. I&#39;ll let the code do the talking:

This is my data:

    #Time	Data in	Data out
    &quot;2013-07-22 15:59:00&quot;	6286	3730
    &quot;2013-07-22 15:58:00&quot;	10695	14589
    &quot;2013-07-22 15:57:00&quot;	17868	26464
    &quot;2013-07-22 15:56:00&quot;	18880	34012
    &quot;2013-07-22 15:55:00&quot;	19206	41192
    &quot;2013-07-22 15:54:00&quot;	20365	43218
    &quot;2013-07-22 15:53:00&quot;	18459	39298
    &quot;2013-07-22 15:52:00&quot;	3420	4686
    &quot;2013-07-22 15:51:00&quot;	3256	4942

And this is the code that is generating the graph:

    gnuplot&gt; set title &quot;Data usage over the last 24 hours&quot;
    gnuplot&gt; unset multiplot
    gnuplot&gt; set xdata time
    gnuplot&gt; set style data lines  
    gnuplot&gt; set term png
    Terminal type set to &#39;png&#39;
    Options are &#39;nocrop font &quot;arial,12&quot; fontscale 1.0 size 640,480 &#39;
    gnuplot&gt; set timefmt &quot;%Y-%m-%d %H:%M:%S&quot;
    gnuplot&gt; set format x &quot;%m-%d\n%H:%M&quot;
    gnuplot&gt; set xlabel &quot;Time&quot;
    gnuplot&gt; set ylabel &quot;Traffic&quot; 
    gnuplot&gt; set autoscale y  
    gnuplot&gt; set xrange [&quot;2013-07-21 16:00&quot;:&quot;2013-07-22 16:00&quot;]
    gnuplot&gt; set output &quot;datausage.png&quot;
    gnuplot&gt; plot &quot;C:\\Users\\blah\\Desktop\\plot.tmp&quot; using 1:2 t &quot;inbound&quot; w lines, &quot;C:\\Users\\blah\\Desktop\\plot.tmp&quot; u 1:3 t &quot;outbound&quot; w lines
                                                                                                                                                                     ^
             all points y value undefined!


Is the problem the space in between `date` and `time` in the x-axis? If not, what do you think could be the problem?

Gnuplot date/time in x axis

I have the following data set.  I would like to use Python or Gnuplot to plot the data.  The tuples are of the form `(x, y)`.  The Y-axis should be a log axis, that is, `log(y)`.  A scatter plot or line plot would be ideal.

How can this be done?

     [(0, 6.0705199999997801e-08), (1, 2.1015700100300739e-08), 
     (2, 7.6280656623374823e-09), (3, 5.7348209304555086e-09), 
     (4, 3.6812203579604238e-09), (5, 4.1572516753310418e-09)]



How do I plot list of tuples in Python?

How do I draw different types of lines on gnuplot? I got to draw different colors. My script joins several files and I think it is why the lines are not dash. Only two of four are dashed.
Thanks
Felipe

    #!/usr/bin/gnuplot
    
    set grid
    set title &#39;Estado dos arquivos no BTRIM com peers de comportamento condicionado&#39;
    set xlabel &#39;Tempo discreto&#39;
    set ylabel &#39;Quantidade de arquivos&#39;
    set style line 1 lc rgb &#39;#0060ad&#39; lt 1 lw 2 pi -1 ps 1.0
    set style line 2 lc rgb &#39;#dd181f&#39; lt 9 lw 2 pi -1 ps 1.0
    set style line 3 lc rgb &#39;#29c524&#39; lt 6 lw 2 pi -1 ps 1.0
    set style line 4 lc rgb &#39;#7D72F9&#39; lt 7 lw 2 pi -1 ps 1.0
    set style line 5 lc rgb &#39;#000000&#39; lt 8 lw 2 pi -1 ps 1.0
    
    set termoption dashed
    #set pointintervalbox 0
    #set boxwidth 0.1
    #set style fill solid
    
    plot &#39;&lt;paste ../00/StatisticNormal.txt ../01/StatisticNormal.txt ../02/StatisticNormal.txt  ../03/StatisticNormal.txt ../04/StatisticNormal.txt ../05/StatisticNormal.txt ../06/StatisticNormal.txt ../07/StatisticNormal.txt ../08/StatisticNormal.txt ../09/StatisticNormal.txt&#39; smooth unique with line ls 1 title &#39;Normais&#39;, \
    &#39;&lt;paste ../00/StatisticVogue.txt ../01/StatisticVogue.txt ../02/StatisticVogue.txt ../03/StatisticVogue.txt ../04/StatisticVogue.txt ../05/StatisticVogue.txt ../06/StatisticVogue.txt ../07/StatisticVogue.txt ../08/StatisticVogue.txt ../09/StatisticVogue.txt&#39; smooth unique with line ls 2 title &#39;na Moda&#39;, \
    &#39;&lt;paste ../00/StatisticPopular.txt ../01/StatisticPopular.txt ../02/StatisticPopular.txt ../03/StatisticPopular.txt ../04/StatisticPopular.txt ../05/StatisticPopular.txt ../06/StatisticPopular.txt ../07/StatisticPopular.txt ../08/StatisticPopular.txt ../09/StatisticPopular.txt&#39; smooth unique with line ls 3 title &#39;Populares&#39;, \
    &#39;&lt;paste ../00/StatisticRarity.txt ../01/StatisticRarity.txt ../02/StatisticRarity.txt ../03/StatisticRarity.txt ../04/StatisticRarity.txt ../05/StatisticRarity.txt ../06/StatisticRarity.txt ../07/StatisticRarity.txt ../08/StatisticRarity.txt ../09/StatisticRarity.txt&#39; smooth unique with line ls 4 title &#39;Raros&#39;
    
    pause -1


Content Type	Original Author	Original Content on Stackoverflow
Question	user494461	View Question on Stackoverflow
Solution 1 - Csv	Thor	View Answer on Stackoverflow
Solution 2 - Csv	Oli4	View Answer on Stackoverflow

Plotting using a CSV file

Csv Problem Overview

Csv Solutions

Solution 1 - Csv

Solution 2 - Csv

How to expire Django session in 5minutes?

Color by Column Values in Matplotlib

Attributions