There is a parameter in the function corresponding to legend; by default it is True

    df.plot(legend=False)

Following is the definition of the `.plot()` method


&gt;Definition: df.plot(frame=None, x=None, y=None, subplots=False, sharex=True, sharey=False, use_index=True, figsize=None, grid=None, legend=True, rot=None, ax=None, style=None, title=None, xlim=None, ylim=None, logx=False, logy=False, xticks=None, yticks=None, kind=&#39;line&#39;, sort_columns=False, fontsize=None, secondary_y=False, **kwds)



In order to remove a legend that has once been drawn, use

    plt.gca().get_legend().remove()

assuming that you have `import`ed `matplotlib.pyplot as plt` or 

    ax.get_legend().remove()

if `ax` is the axes where the legend resides.
 
Alternatively, see Nipun Batras answer if there is some choice to turn the legend off from the beginning in which case one can simply use 

    df.plot(legend=False)

    public class KV&lt;K, V&gt; {
        public K key;
        public V value;
        public KV(K key, V value) {
            this.key = key;
            this.value = value;
        } 
    }



I am trying to refactor the class variable `value`, which happens in place. That means no dialog pops up; I press enter and it tries to refactor across the entire project, including comments and what not, including:

    &lt;%--&lt;link href=&quot;&lt;c:url value=&quot;../core/core.css&quot; /&gt;&quot; /&gt;--%&gt;

in a .jsp file. That is way too &quot;clever&quot; to try to refactor **comments** that match across the entire project. This often causes lots of bug risk, and refactoring in a Java environment is no longer safe. 

The same thing was occurring in Intellij 12. Seriously, I don&#39;t need Intellij to recommend anything that is considered unsafe, or when it is not sure it is the same thing!

I can exclude the refactorings but I don&#39;t have time to evaluate five &quot;suggestions&quot; every time. It just raises the chance of human error: most of the time I just press enter, and woops things are refactored. 

Refactoring is also a major issue in a Java environment when it sometimes tries to replace things in .js files. Seriously, this has to stop. 

Without the popup dialog, I can&#39;t untick &quot;search strings&quot;. Even if that was ticked, Intellij should *never* include the suggestions by default, especially when it is outside the current file. It can recommend to refactor them as well, but they should be excluded by default. That is, it should be an opt-in feature, rather than by default destroying everything. 

This is a serious user experience problem with more recent so called &quot;smart&quot; Intellij refactoring. When refactoring JS files, I don&#39;t want to search Java files for comments or strings! Period! And vice versa! 

Safety comes first! Developers that know what they are doing will search for strings themselves if needed. In a dynamic language environment it makes Intellij impossible to use, because frequently, and without any clear pattern, sometimes refactorings go through, sometimes it changes things across the project and what not.

There should be an option that says, &quot;refactor only relative to this file or when 100% inferred!&quot;, especially for dynamic languages! For static languages it shouldn&#39;t even attempt to look for comments and strings outside the file. 

I didn&#39;t mean to put it out in public, but I have raised this issue over 2 years ago in the bugtracker, but nobody paid any attention.

**EDIT**

For those of you that think that I might be going to far, I just tried this out: 

With this class: 

    public class KV&lt;K, V&gt; {
        public K key;
        public V val;
        public KV(K key, V val) {
            this.key = key;
            this.val = val;
        }
    }

And adding this to **any** Java class, for instance: 

    public class CoreConfig {
        String abc = &quot;kv.val&quot;;
        String def = &quot;somethingElse.val&quot;;
    }


When refactoring `KV.val` as before, I get the following recommendations, an ENTER from disaster and something I have to evaluate and exclude one at a time. It takes effort and is just annoying and risky. It&#39;s like someone yelling out, STOP! And then ooh, nothing after a minute, frustration and a 1000 long word essay ( this ).

![enter image description here][1]


  [1]: http://i.stack.imgur.com/7713o.png

Seriously, is there a way to disable this kind of risky behaviour!? And is there any reason why this is on by default??


**EDIT 20200706**

Shit continues in 2020:
https://youtrack.jetbrains.com/issue/IDEA-245370

Intellij IDEA 13: how do I disable refactor comments and strings?

I am trying to connect postgresql but I am getting this error.

    org.postgresql.util.PSQLException: Connection refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections.

My pg_hba.conf file is like this.

     TYPE  DATABASE        USER            CIDR-ADDRESS            METHOD

    # IPv4 local connections:
    host    all             all             127.0.0.1/32            md5
    # IPv6 local connections:
    host    all             all             ::1/128                 md5

I would be much obliged if anyone please be so kind enough to explain whats hoing on here and how should I correct it.


Postgresql : Connection refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections

Using the pandas library in python and using 

    .plot()

on a dataframe,  how do I display the plot without a legend?



Pandas plot() without a legend

Using the pandas library in python and using
<pre><code class="hljs language-scss">.plot()
</code></pre>
on a dataframe, how do I display the plot without a legend?

I was looking for an elegant way to change a specified column name in a `DataFrame`.

play data ...

    import pandas as pd
    d = {
             &#39;one&#39;: [1, 2, 3, 4, 5],
             &#39;two&#39;: [9, 8, 7, 6, 5],
             &#39;three&#39;: [&#39;a&#39;, &#39;b&#39;, &#39;c&#39;, &#39;d&#39;, &#39;e&#39;]
        }
    df = pd.DataFrame(d)

The most elegant solution I have found so far ...

    names = df.columns.tolist()
    names[names.index(&#39;two&#39;)] = &#39;new_name&#39;
    df.columns = names

I was hoping for a simple one-liner ... this attempt failed ...

    df.columns[df.columns.tolist().index(&#39;one&#39;)] = &#39;another_name&#39;

Any hints gratefully received.

Changing a specific column name in pandas DataFrame

I want to use Intellij Idea within my existing python django project which was built within a virtual environment in ubuntu. How do I configure Intellij Idea to use the libraries of the virtual environment?

Using IntellijIdea within an existing virtualenv

I have the `Python` code:

    from multiprocessing import Process
    
    def f(name):
        print &#39;hello&#39;, name
    
    if __name__ == &#39;__main__&#39;:
        for i in range(0, MAX_PROCESSES):
            p = Process(target=f, args=(i,))
            p.start()

which runs well. However, `MAX_PROCESSES` is variable and can be any value between `1` and `512`. Since I&#39;m only running this code on a machine with `8` cores, I need to find out if it is possible to limit the number of processes allowed to run at the same time. I&#39;ve looked into `multiprocessing.Queue`, but it doesn&#39;t look like what I need - or perhaps I&#39;m interpreting the docs incorrectly.

**Is there a way to limit the number of simultaneous `multiprocessing.Process`s running?**


Using multiprocessing.Process with a maximum number of simultaneous processes

I tried to read the documentation at [http://docs.python.org/dev/library/multiprocessing.html][1] but I&#39;m  still struggling with multiprocessing Queue, Pool and Locking. And for now I was able to build the example below.

Regarding Queue and Pool, I&#39;m not sure if I understood the concept in the right way, so correct me if I&#39;m wrong.  What I&#39;m trying to achieve is to 
process 2 requests at time ( data list have 8 in this example ) so, what should I use? Pool to create 2 processes that can handle two different queues ( 2 at max ) or should I just use Queue to process 2 inputs each time? The lock would be to print the outputs correctly.


    import multiprocessing
    import time
    
    data = ([&#39;a&#39;, &#39;2&#39;], [&#39;b&#39;, &#39;4&#39;], [&#39;c&#39;, &#39;6&#39;], [&#39;d&#39;, &#39;8&#39;],
            [&#39;e&#39;, &#39;1&#39;], [&#39;f&#39;, &#39;3&#39;], [&#39;g&#39;, &#39;5&#39;], [&#39;h&#39;, &#39;7&#39;]
    )
    
    
    def mp_handler(var1):
        for indata in var1:
            p = multiprocessing.Process(target=mp_worker, args=(indata[0], indata[1]))
            p.start()
    
    
    def mp_worker(inputs, the_time):
        print &quot; Processs %s\tWaiting %s seconds&quot; % (inputs, the_time)
        time.sleep(int(the_time))
        print &quot; Process %s\tDONE&quot; % inputs
    
    if __name__ == &#39;__main__&#39;:
        mp_handler(data)

  [1]: http://docs.python.org/dev/library/multiprocessing.html

Dead simple example of using Multiprocessing Queue, Pool and Locking

Consider the following lists:

    a = [&#39;Orange and Banana&#39;, &#39;Orange Banana&#39;]
    b = [&#39;Grapes&#39;, &#39;Orange Banana&#39;]

How to get the following result:
  
    c = [&#39;Orange and Banana&#39;, &#39;Orange Banana&#39;, &#39;Grapes&#39;]

How to get the union of two lists using list comprehension?

I would like to read several csv files from a directory into pandas and concatenate them into one big DataFrame. I have not been able to figure it out though. Here is what I have so far:

    import glob
    import pandas as pd
     
    # get data file names
    path =r&#39;C:\DRO\DCL_rawdata_files&#39;
    filenames = glob.glob(path + &quot;/*.csv&quot;)
    
    dfs = []
    for filename in filenames:
        dfs.append(pd.read_csv(filename))
        
    # Concatenate all data into one DataFrame
    big_frame = pd.concat(dfs, ignore_index=True)

I guess I need some help within the for loop???

Import multiple csv files into pandas and concatenate into one DataFrame

I would like to display a pandas dataframe with a given format using `print()` and the IPython `display()`. For example:

    df = pd.DataFrame([123.4567, 234.5678, 345.6789, 456.7890],
                      index=[&#39;foo&#39;,&#39;bar&#39;,&#39;baz&#39;,&#39;quux&#39;],
                      columns=[&#39;cost&#39;])
    print df

             cost
    foo   123.4567
    bar   234.5678
    baz   345.6789
    quux  456.7890

I would like to somehow coerce this into printing

             cost
    foo   $123.46
    bar   $234.57
    baz   $345.68
    quux  $456.79

without having to modify the data itself or create a copy, just change the way it is displayed.

How can I do this?

How to display pandas DataFrame of floats using a format string for columns?

I have a `DataFrame` like this:

`df`:

     fruit    val1 val2
    0 orange    15    3
    1 apple     10   13
    2 mango     5    5 

How do I get Pandas to give me a cumulative sum and percentage column on only `val1`?

Desired output:

`df_with_cumsum`:

     fruit    val1 val2   cum_sum    cum_perc
    0 orange    15    3    15          50.00
    1 apple     10   13    25          83.33
    2 mango     5    5     30          100.00

I tried `df.cumsum()`, but it&#39;s giving me this error:

&gt;    TypeError: ufunc &#39;isnan&#39; not supported for the input types, and the inputs could not be safely coerced to any supported types according to the casting rule &#39;&#39;safe&#39;&#39;

Cumulative sum and percentage on column?

in a pandas dataframe how can I apply a sort of excel left(&#39;state&#39;,2) to only take the first two letters. Ideally I want to learn how to use left,right and mid in a dataframe too. So need an equivalent and not a &quot;trick&quot; for this specific example.

    data = {&#39;state&#39;: [&#39;Auckland&#39;, &#39;Otago&#39;, &#39;Wellington&#39;, &#39;Dunedin&#39;, &#39;Hamilton&#39;],
    &#39;year&#39;: [2000, 2001, 2002, 2001, 2002],
    &#39;pop&#39;: [1.5, 1.7, 3.6, 2.4, 2.9]}
    df = pd.DataFrame(data)

    print df

         pop       state  year
     0  1.5    Auckland  2000
     1  1.7       Otago  2001
     2  3.6  Wellington  2002
     3  2.4     Dunedin  2001
     4  2.9    Hamilton  2002

I want to get this:

        pop       state     year  StateInitial
     0  1.5       Auckland    2000     Au
     1  1.7       Otago       2001     Ot
     2  3.6       Wellington  2002     We
     3  2.4       Dunedin     2001     Du
     4  2.9       Hamilton    2002     Ha
    

how to do a left,right and mid of a string in a pandas dataframe

By using R, is it possible to place 2 ggplot together (i.e., on the same plot)? I wish to show a trend from 2 different data frames and instead of putting them one next to the other, I&#39;d like to integrate them together in one plot and only to change the color of one of them (the black dot).

To be more specific, I have the following 2 visuals:

    ggplot(visual1, aes(ISSUE_DATE,COUNTED)) + geom_point() + geom_smooth(fill=&quot;blue&quot;, colour=&quot;darkblue&quot;, size=1)

and

    ggplot(visual2, aes(ISSUE_DATE,COUNTED)) + geom_point() + geom_smooth(fill=&quot;red&quot;, colour=&quot;red&quot;, size=1)

They look like this (both have black dots and I&#39;ll need to change one of them to something different):


![enter image description here][1]


and

![enter image description here][2]


  [1]: http://i.stack.imgur.com/sDdJm.png
  [2]: http://i.stack.imgur.com/DBNLZ.png

How to combine 2 plots (ggplot) into one plot?

I am new to python and am trying to plot multiple lines in the same figure using matplotlib.
The value of my Y-axis is stored in a dictionary and I make corresponding values in X-axis in the following code

My code is like this: 

    for i in range(len(ID)):
    AxisY= PlotPoints[ID[i]]
    if len(AxisY)&gt; 5:
        AxisX= [len(AxisY)]
        for i in range(1,len(AxisY)):
            AxisX.append(AxisX[i-1]-1)
        plt.plot(AxisX,AxisY)
        plt.xlabel(&#39;Lead Time (in days)&#39;)
        plt.ylabel(&#39;Proportation of Events Scheduled&#39;)
        ax = plt.gca()
        ax.invert_xaxis()
        ax.yaxis.tick_right()
        ax.yaxis.set_label_position(&quot;right&quot;)
        plt.show()
    
    
But I am getting separate figures with a single plot one by one. Can anybody help me figure out what is wrong with my code? Why can&#39;t I produce multiple-line plotting? Thanks a lot!


Multiple plots in one figure in Python

I have a set of data records like this:

    (s1, t1), (u1, v1), color1
    (s2, t2), (u2, v2), color2
    .
    .
    .
    (sN, tN), (uN, vN), colorN

In any record, the first two values are the **end-points** of a line segment, the third value is the **color** of that line segment. More specifically, &lt;code&gt;(sn, tn)&lt;/code&gt; are the x-y coordinates of the first end-point, &lt;code&gt;(un, vn)&lt;/code&gt; are the x-y coordinates of the second-endpoint. Also, **color** is an rgb with alpha value.

In general, any two line segments are **disconnected** (meaning that their end-points do not necessarily coincide).

How to plot this data using **matplotlib** with a single `plot` call (or as few as possible) as there could be potentially thousands of records.

# Attempts

Preparing the data in one big list and calling `plot` against it is way too slow. For example the following code couldn&#39;t finish in a reasonable amount of time:

    import numpy as np
    import matplotlib.pyplot as plt

    data = []
    for _ in xrange(60000):
        data.append((np.random.rand(), np.random.rand()))
        data.append((np.random.rand(), np.random.rand()))
        data.append(&#39;r&#39;)
    
    print &#39;now plotting...&#39; # from now on, takes too long
    plt.plot(*data)
    print &#39;done&#39;
    #plt.show()

I was able to speed-up the plot rendering by using the **None** insertion trick as follows:

    import numpy as np
    import matplotlib.pyplot as plt
    from timeit import timeit

    N = 60000
    _s = np.random.rand(N)
    _t = np.random.rand(N)
    _u = np.random.rand(N)
    _v = np.random.rand(N)
    x = []
    y = []
    for s, t, u, v in zip(_s, _t, _u, _v):
        x.append(s)
        x.append(u)
        x.append(None)
        y.append(t)
        y.append(v)
        y.append(None)
    print timeit(lambda:plt.plot(x, y), number=1)

This executes in under a second on my machine. I still have to figure out how to embed the color values (RGB with alpha channel). 

Matplotlib: Plotting numerous disconnected line segments with different colors

I have a list of pairs `(a, b)` that I would like to plot with `matplotlib` in python as actual x-y coordinates. Currently, it is making two plots, where the index of the list gives the x-coordinate, and the first plot&#39;s y values are the `a`s in the pairs and the second plot&#39;s y values are the `b`s in the pairs.

To clarify, my data looks like this: `li = [(a,b), (c,d), ... , (t, u)]`
I want to do a one-liner that just calls `plt.plot()` incorrect.
If I didn&#39;t require a one-liner I could trivially do: 

    xs = [x[0] for x in li]
    ys = [x[1] for x in li]
    plt.plot(xs, ys)
 
How can I get matplotlib to plot these pairs as x-y coordinates?

Plotting a list of (x, y) coordinates in python matplotlib

Trying to plot the output of some `Data.Array.Accelerate` computations with `gnuplot` I encountered a strange problem. When run via the interpreter everything is fine, as is plotting straight Haskell data or just printing the Accelerate values, however trying to plot the Accelerate data fails. The error given is `forkOS_entry: interrupted`.

I&#39;ve since realised I should just be more UNIXy and do one thing (well) in each program. But I&#39;m interested in finding out why this fails. I include a minimum code sample below.

    import Prelude hiding (zip,zipWith)
    
    import Graphics.Gnuplot.Simple
    import Data.Array.Accelerate
    -- import Data.Array.Accelerate.Interpreter
    import Data.Array.Accelerate.CUDA
    
    f :: Vector Float -&gt; Vector Float -&gt; Acc (Vector Float)
    f xs ys = let xs&#39; = use xs
                  ys&#39; = use ys
              in
                 (zipWith (*) xs&#39; ys&#39;)
    n=10::Int
    
    points = toList.run $ f (fromList (Z:.n) [1..10]) (fromList (Z:.n) [-5..4])
    
    main = plotList [] points

**update 2014/09/11**

Based on `user2141650`&#39;s suggestion (thanks!) changing the last line to

    plotList [] $! points

fixes the problem. In fact it makes the plot actually appear, whereas without this the program would finish with or without error but would never actually display the plot. I suppose I&#39;d accept this as an answer if it was written up, but it would still be nice to know what&#39;s going on.

Possibly related:

 - https://stackoverflow.com/questions/17554008/forkos-entry-interrupted-error-what-is-this

(By the way, please stop trying to edit for grammar. There isn&#39;t anything wrong with the question as is, I am a native speaker and write exactly what I mean. Thank you for your contribution though.)

Content Type	Original Author	Original Content on Stackoverflow
Question	Bilal Syed Hussain	View Question on Stackoverflow
Solution 1 - Python	Nipun Batra	View Answer on Stackoverflow
Solution 2 - Python	ImportanceOfBeingErnest	View Answer on Stackoverflow

Pandas plot() without a legend

Python Problem Overview

Python Solutions

Solution 1 - Python

Solution 2 - Python

Postgresql : Connection refused. Check that the hostname and port are correct and that the postmaster is accepting TCP/IP connections

Intellij IDEA 13: how do I disable refactor comments and strings?

Attributions