I think @Evert has the right answer:

    plt.scatter(dates,values)
    plt.plot(dates, values)
    plt.show()

Which is pretty much the same as 

    plt.plot(dates, values, &#39;-o&#39;)
    plt.show()

You can replace `-o` with another suitable *format string* as described in the [documentation](https://matplotlib.org/stable/api/_as_gen/matplotlib.pyplot.plot.html).
You can also split the choices of line and marker styles using the `linestyle=` and `marker=` keyword arguments.


For red lines an points

    plt.plot(dates, values, &#39;.r-&#39;) 

or for x markers and blue lines

    plt.plot(dates, values, &#39;xb-&#39;)



In addition to what provided in the other answers, the keyword &quot;zorder&quot; allows one to decide the order in which different objects are plotted vertically.
E.g.:

    plt.plot(x,y,zorder=1) 
    plt.scatter(x,y,zorder=2)

plots the scatter symbols on top of the line, while

    plt.plot(x,y,zorder=2)
    plt.scatter(x,y,zorder=1)
plots the line over the scatter symbols.

 
See, e.g., the [zorder demo][1]

  [1]: http://matplotlib.org/examples/pylab_examples/zorder_demo.html

They keyword argument for this is `marker`, and you can set the size of the marker with `markersize`. To generate a line with scatter symbols on top:

    plt.plot(x, y, marker = &#39;.&#39;, markersize = 10)

To plot a filled spot, you can use marker `&#39;.&#39;` or `&#39;o&#39;` (the lower case letter oh). For a list of all markers, see:    
https://matplotlib.org/stable/api/markers_api.html

I am creating a batch file with some simple commands to gather information from a system. The batch file contains commands to get the time, IP information, users, etc.  

I assembled all the commands in a batch file, and it runs, but I would like the batch file, when run to output the results to a text file (log). Is there a command that I can add to the batch that would do so?  

Keep in mind I do not want to run the batch from cmd, then redirect output ; I want to redirect the output from inside the batch, if that is possible.


Redirecting Output from within Batch file

I am new to the Java world and JPA. I was studying JPA and came across many new terms like Entity, persistence. While reading, I could not understand the exact definition for **Persistence Context**.

Can anyone explain it in simple laymen terms? What is it to do with the data used in the `@Entity`?

For example, I find this definition too complicated to understand:
&gt; A persistence context is a set of entities such that for any persistent identity there is a unique entity instance.

What is Persistence Context?

I have two lists, dates and values. I want to plot them using matplotlib. The following creates a scatter plot of my data.

    import matplotlib.pyplot as plt
    
    plt.scatter(dates,values)
    plt.show()


`plt.plot(dates, values)` creates a line graph.

But what I really want is a scatterplot where the points are connected by a line.

Similar to in R:

    plot(dates, values)
    lines(dates, value, type=&quot;l&quot;)
, which gives me a scatterplot of points overlaid with a line connecting the points.

How do I do this in python?

Matplotlib connect scatterplot points with line - Python

I have two lists, dates and values. I want to plot them using matplotlib. The following creates a scatter plot of my data.
<pre><code class="hljs language-javascript">import matplotlib.pyplot as plt

plt.scatter(dates,values)
plt.show()
</code></pre>
<code>plt.plot(dates, values)</code> creates a line graph.
But what I really want is a scatterplot where the points are connected by a line.
Similar to in R:
<pre><code class="hljs language-scss">plot(dates, values)
lines(dates, value, type="l")
</code></pre>
, which gives me a scatterplot of points overlaid with a line connecting the points.
How do I do this in python?

I have some nodes coming from a script that I want to map on to a graph. In the below, I want to use Arrow to go from A to D and probably have the edge colored too in (red or something).

This is basically, like a path from A to D when all other nodes are present. you can imagine each nodes as cities and traveling from A to D requires directions (with arrow heads).

This code below builds the graph

    import networkx as nx
    import numpy as np
    import matplotlib.pyplot as plt
    
    G = nx.Graph()
    G.add_edges_from(
        [(&#39;A&#39;, &#39;B&#39;), (&#39;A&#39;, &#39;C&#39;), (&#39;D&#39;, &#39;B&#39;), (&#39;E&#39;, &#39;C&#39;), (&#39;E&#39;, &#39;F&#39;),
         (&#39;B&#39;, &#39;H&#39;), (&#39;B&#39;, &#39;G&#39;), (&#39;B&#39;, &#39;F&#39;), (&#39;C&#39;, &#39;G&#39;)])
    
    val_map = {&#39;A&#39;: 1.0,
               &#39;D&#39;: 0.5714285714285714,
               &#39;H&#39;: 0.0}
    
    values = [val_map.get(node, 0.25) for node in G.nodes()]
    
    nx.draw(G, cmap = plt.get_cmap(&#39;jet&#39;), node_color = values)
    plt.show()

but I want something like shown in the image.![enter image description here][1]
![enter image description here][2]

Arrow heads of the first image and the edges in red color onto the second image.


  [1]: http://i.stack.imgur.com/VW9yr.png
  [2]: http://i.stack.imgur.com/UEFdh.png

how to draw directed graphs using networkx in python?

I have only a single key-value pair in a dictionary. I want to assign key to one variable
and it&#39;s value to another variable. I have tried with below ways but I am getting error for same.
 
    &gt;&gt;&gt; d = {&quot;a&quot;: 1}
    
    &gt;&gt;&gt; d.items()
    [(&#39;a&#39;, 1)]
    
    &gt;&gt;&gt; (k, v) = d.items()
    Traceback (most recent call last):
      File &quot;&lt;stdin&gt;&quot;, line 1, in &lt;module&gt;
    ValueError: need more than 1 value to unpack
    
    &gt;&gt;&gt; (k, v) = list(d.items())
    Traceback (most recent call last):
      File &quot;&lt;stdin&gt;&quot;, line 1, in &lt;module&gt;
    ValueError: need more than 1 value to unpack

I know that we can extract key and value one by one, or by for loop and `iteritems()`, but isn&#39;t there a simple way such that we can assign both in a single statement? 


How to extract dictionary single key-value pair in variables

My question is the same as this previous one:

https://stackoverflow.com/questions/18921570/binning-with-zero-values-in-pandas

however, I still want to include the 0 values in a fractile.  Is there a way to do this?  In other words, if I have 600 values, 50% of which are 0, and the rest are let&#39;s say between 1 and 100, how would I categorize all the 0 values in fractile 1, and then the rest of the non-zero values in fractile labels 2 to 10 (assuming I want 10 fractiles).  Could I convert the 0&#39;s to nan, qcut the remaining non nan data into 9 fractiles (1 to 9), then add 1 to each label (now 2 to 10) and label all the 0 values as fractile 1 manually?  Even this is tricky, because in my data set in addition to the 600 values, I also have another couple hundred which may already be nan before I would convert the 0s to nan.

Update 1/26/14:

I came up with the following interim solution.  The problem with this code though, is if the high frequency value is not on the edges of the distribution, then it inserts an extra bin in the middle of the existing set of bins and throws everything a little (or a lot) off.

    def fractile_cut(ser, num_fractiles):
        num_valid = ser.valid().shape[0]
        remain_fractiles = num_fractiles
        vcounts = ser.value_counts()
        high_freq = []
        i = 0
        while vcounts.iloc[i] &gt; num_valid/ float(remain_fractiles):
            curr_val = vcounts.index[i]
            high_freq.append(curr_val)
            remain_fractiles -= 1
            num_valid = num_valid - vcounts[i]
            i += 1
        curr_ser = ser.copy()
        curr_ser = curr_ser[~curr_ser.isin(high_freq)]
        qcut = pd.qcut(curr_ser, remain_fractiles, retbins=True)
        qcut_bins = qcut[1]
        all_bins = list(qcut_bins)
        for val in high_freq:
            bisect.insort(all_bins, val)
        cut = pd.cut(ser, bins=all_bins)
        ser_fractiles = pd.Series(cut.labels + 1, index=ser.index)
        return ser_fractiles



How to qcut with non unique bin edges?

I thought that `nargs=&#39;*&#39;` was enough to handle a variable number of arguments. Apparently it&#39;s not, and I don&#39;t understand the cause of this error.

The code:

    p = argparse.ArgumentParser()
    p.add_argument(&#39;pos&#39;)
    p.add_argument(&#39;foo&#39;)
    p.add_argument(&#39;--spam&#39;, default=24, type=int, dest=&#39;spam&#39;)
    p.add_argument(&#39;vars&#39;, nargs=&#39;*&#39;)

    p.parse_args(&#39;1 2 --spam 8 8 9&#39;.split())

I think the resulting namespace should be `Namespace(pos=&#39;1&#39;, foo=&#39;2&#39;, spam=&#39;8&#39;, vars=[&#39;8&#39;, &#39;9&#39;])`. Instead, argparse gives this error:

    usage: prog.py [-h] [--spam SPAM] pos foo [vars [vars ...]]
    error: unrecognized arguments: 9 8

Basically, argparse doesn&#39;t know where to put those additional arguments... Why is that?

Argparse: how to handle variable number of arguments (nargs=&#39;*&#39;)

I am struggling with the following problem:
I want to convert an `OrderedDict` like this:

    OrderedDict([(&#39;method&#39;, &#39;constant&#39;), (&#39;data&#39;, &#39;1.225&#39;)])

into a regular dict like this:

    {&#39;method&#39;: &#39;constant&#39;, &#39;data&#39;:1.225}

because I have to store it as string in a database. After the conversion the order is not important anymore, so I can spare the ordered feature anyway.

Thanks for any hint or solutions,

Ben

How to convert an OrderedDict into a regular dict in python3

I have installed Python 2.5.4, Numpy 1.5.0 win32, Matplotlib 1.0.0 win32, pywin32 218. Still not able to plot graphs in Python. Here is the error I am getting :

          import pylab
       File &quot;C:\Python25\lib\site-packages\pylab.py&quot;, line 1, in &lt;module&gt;
          from matplotlib.pylab import *
       File &quot;C:\Python25\lib\site-packages\matplotlib\pylab.py&quot;, line 216, in &lt;module&gt;
          from matplotlib import mpl  # pulls in most modules
       File &quot;C:\Python25\lib\site-packages\matplotlib\mpl.py&quot;, line 1, in &lt;module&gt;
          from matplotlib import artist
       File &quot;C:\Python25\lib\site-packages\matplotlib\artist.py&quot;, line 6, in &lt;module&gt;
          from transforms import Bbox, IdentityTransform, TransformedBbox, TransformedPath
       File &quot;C:\Python25\lib\site-packages\matplotlib\transforms.py&quot;, line 34, in &lt;module&gt;
          from matplotlib._path import affine_transform
    ImportError: DLL load failed: The specified module could not be found.

Please kindly help.. 

ImportError: DLL load failed: The specified module could not be found

Is there a simple/clean way to iterate an array of axis returned by subplots like 


    nrow = ncol = 2
    a = []
    fig, axs = plt.subplots(nrows=nrow, ncols=ncol)
    for i, row in enumerate(axs):
        for j, ax in enumerate(row):
            a.append(ax)
             
    for i, ax in enumerate(a):
        ax.set_ylabel(str(i))

which even works for `nrow` or `ncol == 1`.

I tried list comprehension like:

    [element for tupl in tupleOfTuples for element in tupl]

but that fails if `nrows` or `ncols == 1` 

matplotlib iterate subplot axis array through single list

The labels on my horizontal colorbar are too close together and I don&#39;t want to reduce text size further:

    cbar = plt.colorbar(shrink=0.8, orientation=&#39;horizontal&#39;, extend=&#39;both&#39;, pad=0.02)
    cbar.ax.tick_params(labelsize=8)

![horizontal colorbar with bad labels][1]

I&#39;d like to preserve all ticks, but remove every other label.  

Most examples I&#39;ve found pass a user-specified list of strings to cbar.set_ticklabels().  I&#39;m looking for a general solution.  

I played around with variations of

    cbar.set_ticklabels(cbar.get_ticklabels()[::2])

and

    cbar.ax.xaxis.set_major_locator(matplotlib.ticker.MaxNLocator(nbins=4))

but I haven&#39;t found the magic combination.  

I know there must be a clean way to do this using a locator object.  


  [1]: http://i.stack.imgur.com/t52fd.png

Cleanest way to hide every nth tick label in matplotlib colorbar?

I&#39;m trying to colorize a Voronoi Diagram created using [`scipy.spatial.Voronoi`][1]. Here&#39;s my code:

    import numpy as np
    import matplotlib.pyplot as plt
    from scipy.spatial import Voronoi, voronoi_plot_2d

    # make up data points
    points = np.random.rand(15,2)

    # compute Voronoi tesselation
    vor = Voronoi(points)

    # plot
    voronoi_plot_2d(vor)

    # colorize
    for region in vor.regions:
        if not -1 in region:
            polygon = [vor.vertices[i] for i in region]
            plt.fill(*zip(*polygon))

    plt.show()

The resulting image:

![Voronoi Diagram][2]

As you can see some of the Voronoi regions at the border of the image are not colored. That is because some indices to the Voronoi vertices for these regions are set to `-1`, i.e., for those vertices outside the Voronoi diagram. According to the docs:

&gt; _regions:_ (list of list of ints, shape (nregions, *)) Indices of the Voronoi vertices forming each Voronoi region. **-1 indicates vertex outside the Voronoi diagram.**

In order to colorize these regions as well, I&#39;ve tried to just remove these &quot;outside&quot; vertices from the polygon, but that didn&#39;t work. I think, I need to fill in some points at the border of the image region, but I can&#39;t seem to figure out how to achieve this reasonably.

Can anyone help?

  [1]: http://docs.scipy.org/doc/scipy-dev/reference/generated/scipy.spatial.Voronoi.html
  [2]: http://i.stack.imgur.com/vmZpK.png

Colorize Voronoi Diagram

When performing `pip install -r requirements.txt`, I get the following error during the stage where it is installing `matplotlib`:


    REQUIRED DEPENDENCIES AND EXTENSIONS
                     numpy: yes [not found. pip may install it below.]
                  dateutil: yes [dateutil was not found. It is required for date
                            axis support. pip/easy_install may attempt to
                            install it after matplotlib.]
                   tornado: yes [tornado was not found. It is required for the
                            WebAgg backend. pip/easy_install may attempt to
                            install it after matplotlib.]
                 pyparsing: yes [pyparsing was not found. It is required for
                            mathtext support. pip/easy_install may attempt to
                            install it after matplotlib.]
                     pycxx: yes [Couldn&#39;t import.  Using local copy.]
                    libagg: yes [pkg-config information for &#39;libagg&#39; could not
                            be found. Using local copy.]
                  freetype: no  [pkg-config information for &#39;freetype2&#39; could
                            not be found.]

   ...


    The following required packages can not be built:

                        * freetype

Shouldn&#39;t `pip install -r requirements.txt` also install freetype? How should freetype be installed in Ubuntu 12.04 so it works with `matplotlib`?

Content Type	Original Author	Original Content on Stackoverflow
Question	brno792	View Question on Stackoverflow
Solution 1 - Python	Hannes Ovrén	View Answer on Stackoverflow
Solution 2 - Python	Steve Barnes	View Answer on Stackoverflow
Solution 3 - Python	Use Me	View Answer on Stackoverflow
Solution 4 - Python	eric	View Answer on Stackoverflow

Matplotlib connect scatterplot points with line - Python

Python Problem Overview

Python Solutions

Solution 1 - Python

Solution 2 - Python

Solution 3 - Python

Solution 4 - Python

What is Persistence Context?

Redirecting Output from within Batch file

Attributions