PIL&#39;s `__init__.py` is just an empty stub as is common. It won&#39;t magically import anything by itself.

When you do `from PIL import Image` it looks in the PIL package and finds the file Image.py and imports that. When you do `PIL.Image` you are actually doing an attribute lookup on the PIL module (which is just an empty stub unless you explicitly import stuff).

In fact, importing a module usually __doesn&#39;t__ import submodules. `os.path` is a famous exception, since the os module is magic. 


More info:  
[The Image Module][1]

[1]: http://effbot.org/imagingbook/image.htm

If you, like me, found the accepted answer a bit befuddling because you could *swear* you&#39;ve been able to use

```python
import PIL
PIL.Image
```

sometimes before, a potential reason for this is if **any** other code in your Python session has run `from PIL import Image` or `import PIL.Image`, even if it&#39;s in a completely different scope, *you will be able to access `PIL.Image`*.

In particular, `matplotlib` does so when it&#39;s imported. So if you run

```
import matplotlib
import PIL
PIL.Image
```

*it works*. Thanks, Python.

Don&#39;t trust anyone. Don&#39;t trust Python. Use `import PIL.Image`.

You can do:

    try:
        import Image
    except ImportError:
        from PIL import Image

it&#39;s better to use pillow instead PIL.

Differentiate between function overloading and function overriding in C++?

Differentiate between function overloading and function overriding

How can I best handle a situation like the following? 

I have a constructor that takes a while to complete.

    var Element = function Element(name){
       this.name = name;
       this.nucleus = {};
  
       this.load_nucleus(name); // This might take a second.
    }

    var oxygen = new Element(&#39;oxygen&#39;);
    console.log(oxygen.nucleus); // Returns {}, because load_nucleus hasn&#39;t finished.

I see three options, each of which seem out of the ordinary.

**One**, add a callback to the constructor.

    var Element = function Element(name, fn){
       this.name = name;
       this.nucleus = {};
       
       this.load_nucleus(name, function(){
          fn(); // Now continue.
       });
    }

    Element.prototype.load_nucleus(name, fn){
       fs.readFile(name+&#39;.json&#39;, function(err, data) {
          this.nucleus = JSON.parse(data); 
          fn();
       });
    }

    var oxygen = new Element(&#39;oxygen&#39;, function(){  
       console.log(oxygen.nucleus);
    });

**Two**, use EventEmitter to emit a &#39;loaded&#39; event.

    var Element = function Element(name){
       this.name = name;
       this.nucleus = {};
  
       this.load_nucleus(name); // This might take a second.
    }

    Element.prototype.load_nucleus(name){
       var self = this;
       fs.readFile(name+&#39;.json&#39;, function(err, data) {
          self.nucleus = JSON.parse(data); 
          self.emit(&#39;loaded&#39;);
       });
    }

    util.inherits(Element, events.EventEmitter);

    var oxygen = new Element(&#39;oxygen&#39;);
    oxygen.once(&#39;loaded&#39;, function(){
       console.log(this.nucleus);
    });

**Or three**, block the constructor.

    var Element = function Element(name){
       this.name = name;
       this.nucleus = {};
  
       this.load_nucleus(name); // This might take a second.
    }

    Element.prototype.load_nucleus(name, fn){
       this.nucleus = JSON.parse(fs.readFileSync(name+&#39;.json&#39;));
    }

    var oxygen = new Element(&#39;oxygen&#39;);
    console.log(oxygen.nucleus)

But I haven&#39;t seen any of this done before.  

What other options do I have?

Asynchronous constructor

I&#39;m using python2.6 and got a problem this morning. It said &#39;module&#39; has no attribute &#39;Image&#39;. Here is my input. Why the first time I can not use PIL.Image?

    &gt;&gt;&gt; import PIL
    &gt;&gt;&gt; PIL.Image
    Traceback (most recent call last):
      File &quot;&lt;stdin&gt;&quot;, line 1, in &lt;module&gt;
    AttributeError: &#39;module&#39; object has no attribute &#39;Image&#39;
    &gt;&gt;&gt; from PIL import Image
    &gt;&gt;&gt; Image
    &lt;module &#39;PIL.Image&#39; from &#39;/usr/lib/python2.6/dist-packages/PIL/Image.pyc&#39;&gt;
    &gt;&gt;&gt; PIL.Image
    &lt;module &#39;PIL.Image&#39; from &#39;/usr/lib/python2.6/dist-packages/PIL/Image.pyc&#39;&gt;



Python PIL has no attribute &#39;Image&#39;

I'm using python2.6 and got a problem this morning. It said 'module' has no attribute 'Image'. Here is my input. Why the first time I can not use PIL.Image?
<pre><code class="hljs language-python">>>> import PIL
>>> PIL.Image
Traceback (most recent call last):
 File "&#x3C;stdin>", line 1, in &#x3C;module>
AttributeError: 'module' object has no attribute 'Image'
>>> from PIL import Image
>>> Image
&#x3C;module 'PIL.Image' from '/usr/lib/python2.6/dist-packages/PIL/Image.pyc'>
>>> PIL.Image
&#x3C;module 'PIL.Image' from '/usr/lib/python2.6/dist-packages/PIL/Image.pyc'>
</code></pre>

I am using Python 3.2.1 and I can&#39;t import the `StringIO` module. I use 
`io.StringIO` and it works, but I can&#39;t use it with `numpy`&#39;s `genfromtxt` like this:

    x=&quot;1 3\n 4.5 8&quot;        
    numpy.genfromtxt(io.StringIO(x))

I get the following error:

    TypeError: Can&#39;t convert &#39;bytes&#39; object to str implicitly  

and when I write `import StringIO` it says

    ImportError: No module named &#39;StringIO&#39;

How to use StringIO in Python3?

I just started using pandas/matplotlib as a replacement for Excel to generate stacked bar charts.  I am running into an issue  

(1) there are only 5 colors in the default colormap, so if I have more than 5 categories then the colors repeat.  How can I specify more colors?  Ideally, a gradient with a start color and an end color, and a way to dynamically generate n colors in between?

(2) the colors are not very visually pleasing.  How do I specify a custom set of n colors?  Or, a gradient would also work.

An example which illustrates both of the above points is below:

      4 from matplotlib import pyplot
      5 from pandas import *
      6 import random
      7 
      8 x = [{i:random.randint(1,5)} for i in range(10)]
      9 df = DataFrame(x)
     10 
     11 df.plot(kind=&#39;bar&#39;, stacked=True)

And the output is this:

![enter image description here][1]



  [1]: http://i.stack.imgur.com/SC7g4.png

How to give a pandas/matplotlib bar graph custom colors

I have checked all of the other questions with the same error yet found no helpful solution =/

I have a dictionary of lists:

    d = {&#39;a&#39;: [1], &#39;b&#39;: [1, 2], &#39;c&#39;: [], &#39;d&#39;:[]}

in which some of the values are empty. At the end of creating these lists, I want to remove these empty lists before returning my dictionary. Current I am attempting to do this as follows:

    for i in d:
        if not d[i]:
            d.pop(i)

however, this is giving me the runtime error. I am aware that you cannot add/remove elements in a dictionary while iterating through it...what would be a way around this then?

How to avoid &quot;RuntimeError: dictionary changed size during iteration&quot; error?

I am trying to send a simple dictionary to a json file from python, but I keep getting the &quot;TypeError: 1425 is not JSON serializable&quot; message.

    import json
    alerts = {&#39;upper&#39;:[1425],&#39;lower&#39;:[576],&#39;level&#39;:[2],&#39;datetime&#39;:[&#39;2012-08-08 15:30&#39;]}
    afile = open(&#39;test.json&#39;,&#39;w&#39;)
    afile.write(json.dumps(alerts,encoding=&#39;UTF-8&#39;))
    afile.close()

If I add the default argument, then it writes, but the integer values are written to the json file as strings, which is undesirable.

    afile.write(json.dumps(alerts,encoding=&#39;UTF-8&#39;,default=str))


&quot;TypeError: (Integer) is not JSON serializable&quot; when serializing JSON in Python?

I want to see if a field/variable is none within a Django template. What is the correct syntax for that?

This is what I currently have:

    {% if profile.user.first_name is null %}
      &lt;p&gt; -- &lt;/p&gt;
    {% elif %}
      {{ profile.user.first_name }} {{ profile.user.last_name }}
    {% endif%}


In the example above, what would I use to replace &quot;null&quot;?

What is the equivalent of &quot;none&quot; in django templates?

I fear that this is a messy way to approach the problem but... 

let&#39;s say that I want to make some imports in Python based on some conditions.

For this reason I want to write a function:

    def conditional_import_modules(test):
        if test == &#39;foo&#39;:
            import onemodule, anothermodule
        elif test == &#39;bar&#39;:
            import thirdmodule, and_another_module
        else:
            import all_the_other_modules

Now how can I have the imported modules globally available?

For example:

    conditional_import_modules(test=&#39;bar&#39;)
    thirdmodule.myfunction()



How to make global imports from a function?

Having already use flat packages, I was not expecting the issue I encountered with nested packages. Here is…


# Directory layout

    dir
     |
     +-- test.py
     |
     +-- package
          |
          +-- __init__.py
          |
          +-- subpackage
               |
               +-- __init__.py
               |
               +-- module.py

# Content of __init__.py

Both `package/__init__.py` and `package/subpackage/__init__.py` are empty.

# Content of `module.py`

    # file `package/subpackage/module.py`
    attribute1 = &quot;value 1&quot;
    attribute2 = &quot;value 2&quot;
    attribute3 = &quot;value 3&quot;
    # and as many more as you want...

# Content of `test.py` (3 versions)

## Version 1

    # file test.py
    from package.subpackage.module import *
    print attribute1 # OK

That&#39;s the bad and unsafe way of importing things (import all in a bulk), but it works.

## Version 2

    # file test.py
    import package.subpackage.module
    from package.subpackage import module # Alternative
    from module import attribute1

A safer way to import, item by item, but it fails, Python don&#39;t want this: fails with the message: &quot;No module named module&quot;. However&#160;…

    # file test.py
    import package.subpackage.module
    from package.subpackage import module # Alternative
    print module # Surprise here

…&#160;says `&lt;module &#39;package.subpackage.module&#39; from &#39;...&#39;&gt;`. So that&#39;s a module, but that&#39;s not a module /-P 8-O ... uh

## Version 3

    # file test.py v3
    from package.subpackage.module import attribute1
    print attribute1 # OK

This one works. So you are either forced to use the overkill prefix all the time or use the unsafe way as in version #1 and disallowed by Python to use the safe handy way? The better way, which is safe and avoid unecessary long prefix is the only one which Python reject? Is this because it loves `import *` or because it loves overlong prefixes (which does not help to enforce this practice)?.

Sorry for the hard words, but that&#39;s two days I trying to work around this stupid‑like behavior. Unless I was totally wrong somewhere, this will leave me with a feeling something is really broken in Python&#39;s model of package and sub‑packages.

Notes 

 * I don&#39;t want to rely on `sys.path`, to avoid global side effects, nor on `*.pth` files, which are just another way to play with `sys.path` with the same global effets. For the solution to be clean, it has to be local only. Either Python is able to handle subpackage, either it&#39;s not, but it should not require to play with global configuration to be able to handle local stuff.
 * I also tried use imports in `package/subpackage/__init__.py`, but it solved nothing, it do the same, and complains `subpackage` is not a known module, while `print subpackage` says it&#39;s a module (weird behavior, again).

May be I&#39;m entirely wrong tough (the option I would prefer), but this make me feel a lot disappointed about Python.

Any other known way beside of the three I tried? Something I don&#39;t know about?

(sigh)


----- %&lt; ----- edit ----- &gt;% -----

# Conclusion so far (after people&#39;s comments)

There is nothing like real sub‑package in Python, as all package references goes to a global dictionnary, only, which means there&#39;s no local dictionary, which implies there&#39;s is no way to manage local package reference.

You have to either use full prefix or short prefix or alias. As in:

## Full prefix version

    from package.subpackage.module import attribute1
    # An repeat it again an again
    # But after that, you can simply:
    use_of (attribute1)

## Short prefix version (but repeated prefix)

    from package.subpackage import module
    # Short but then you have to do:
    use_of (module.attribute1)
    # and repeat the prefix at every use place

Or else, a variation of the above.

    from package.subpackage import module as m
    use_of (m.attribute1)
    # `m` is a shorter prefix, but you could as well
    # define a more meaningful name after the context

# Factorized version

If you don&#39;t mind about importing multiple entity all at once in a batch, you can:

    from package.subpackage.module import attribute1, attribute2
    # and etc.

Not in my first favorite taste (I prefer to have one import statement per imported entity), but may be the one I will personally favor.

_Update (2012-09-14):_

Finally appears to be OK in practice, except with a comment about the layout. Instead of the above, I used:

    from package.subpackage.module import (

        attribute1, 
        attribute2,
        attribute3,
        ...)  # and etc.


Python: importing a sub‑package or sub‑module

Is there a way to remove unused imports in Intellij IDEA on commit?

It is not very optimal to do it manually, &lt;kbd&gt;CTRL&lt;/kbd&gt; + &lt;kbd&gt;ALT&lt;/kbd&gt; + &lt;kbd&gt;O&lt;/kbd&gt; helps but it&#39;s still manual.

How to remove unused imports in Intellij IDEA on commit?

does somebody know how to do a module.exports?

I tried some different ways ending up with

&lt;!-- language: typescript --&gt;

    export class Greeter {}

which will compile to

&lt;!-- language: typescript --&gt;

    exports.Greeter = Greeter;

But what I really want is this:

    exports = Greeter;

So that I can use it like this:

&lt;!-- language: typescript --&gt;

    import { Greeter } from &quot;greeter&quot;;
    
    const greeter = new Greeter();

and not

&lt;!-- language: typescript --&gt;

    import { Greeter } from &quot;greeter&quot;;
    
    const greeter = new Greeter.Greeter();

Is this possible with Typescript?

module.exports in typescript

I have a `.csv` file in my workstation. How can I open that file in R and do statistical calculation?

How do I import a CSV file in R?

I am doing some image editing with the PIL libary. The point is, that I don&#39;t want to save the image each time on my HDD to view it in Explorer. Is there a small module that simply enables me to set up a window and display the image?

How to show PIL images on the screen?

I think this problem is not Zope-related. Nonetheless I&#39;ll explain what I&#39;m trying to do:

I&#39;m using a PUT_factory in Zope to upload images to the ZODB per FTP. The uploaded image is saved as a Zope Image inside a newly created container object. This works fine, but I want to resize the image if it exceeds a certain size (width and height). So I&#39;m using the thumbnail function of PIL to resize them i.e. to 200x200. This works fine as long as the uploaded images are relatively small. I didn&#39;t check out the exact limit, but 976x1296px is still ok.

With bigger pictures I get: 

    Module PIL.Image, line 1559, in thumbnail
    Module PIL.ImageFile, line 201, in load
    IOError: image file is truncated (nn bytes not processed).

I tested a lot of jpegs from my camera. I don&#39;t think they are all truncated.

Here is my code:

    if img and img.meta_type == &#39;Image&#39;:
      pilImg = PIL.Image.open( StringIO(str(img.data)) )
    elif imgData:
      pilImg = PIL.Image.open( StringIO(imgData) )

    pilImg.thumbnail((width, height), PIL.Image.ANTIALIAS)

As I&#39;m using a PUT_factory, I don&#39;t have a file object, I&#39;m using either the raw data from the factory or a previously created (Zope) Image object.

I&#39;ve heard that PIL handles image data differently when a certain size is exceeded, but I don&#39;t know how to adjust my code. Or is it related to PIL&#39;s lazy loading?

PIL &quot;IOError: image file truncated&quot; with big images

I am looking for how to resample a numpy array representing image data at a new size, preferably having a choice of the interpolation method (nearest, bilinear, etc.). I know there is

    scipy.misc.imresize

which does exactly this by wrapping PIL&#39;s resize function. The only problem is that since it uses PIL, the numpy array has to conform to image formats, giving me a maximum of 4 &quot;color&quot; channels.

I want to be able to resize arbitrary images, with any number of &quot;color&quot; channels. I was wondering if there is a simple way to do this in scipy/numpy, or if I need to roll my own.

I have two ideas for how to concoct one myself:

 * a function that runs `scipy.misc.imresize` on every channel separately
 * create my own using `scipy.ndimage.interpolation.affine_transform`

The first one would probably be slow for large data, and the second one does not seem to offer any other interpolation method except splines.


Resampling a numpy array representing an image

My work recently involves programmatically making videos. In python, the typical workflow looks something like this:

    import subprocess, Image, ImageDraw

    for i in range(frames_per_second * video_duration_seconds):
        img = createFrame(i)
        img.save(&quot;%07d.png&quot; % i)

    subprocess.call([&quot;ffmpeg&quot;,&quot;-y&quot;,&quot;-r&quot;,str(frames_per_second),&quot;-i&quot;, &quot;%07d.png&quot;,&quot;-vcodec&quot;,&quot;mpeg4&quot;, &quot;-qscale&quot;,&quot;5&quot;, &quot;-r&quot;, str(frames_per_second), &quot;video.avi&quot;])

This workflow creates an image for each frame in the video and saves it to disk. After all images have been saved, ffmpeg is called to construct a video from all of the images.

Saving the images to disk (not the creation of the images in memory) consumes the majority of the cycles here, and does not appear to be necessary. Is there some way to perform the same function, but without saving the images to disk? So, ffmpeg would be called and the images would be constructed and fed to ffmpeg immediately after being constructed.

Can you &quot;stream&quot; images to ffmpeg to construct a video, instead of saving them to disk?

I&#39;m trying to convert image from `PIL` to `OpenCV` format. I&#39;m using `OpenCV 2.4.3`.
here is what I&#39;ve attempted till now.

    &gt;&gt;&gt; from PIL import Image
    &gt;&gt;&gt; import cv2 as cv
    &gt;&gt;&gt; pimg = Image.open(&#39;D:\\traffic.jpg&#39;)                           #PIL Image
    &gt;&gt;&gt; cimg = cv.cv.CreateImageHeader(pimg.size,cv.IPL_DEPTH_8U,3)    #CV Image
    &gt;&gt;&gt; cv.cv.SetData(cimg,pimg.tostring())
    &gt;&gt;&gt; cv.cv.NamedWindow(&#39;cimg&#39;)
    &gt;&gt;&gt; cv.cv.ShowImage(&#39;cimg&#39;,cimg)
    &gt;&gt;&gt; cv.cv.WaitKey()

But I think the image is not getting converted to CV format. The Window shows me a large brown image.
Where am I going wrong in Converting image from `PIL` to `CV` format?

 Also , why do i need to type `cv.cv` to access functions?



Content Type	Original Author	Original Content on Stackoverflow
Question	Squall	View Question on Stackoverflow
Solution 1 - Python	Antimony	View Answer on Stackoverflow
Solution 2 - Python	convoliution	View Answer on Stackoverflow
Solution 3 - Python	Reza-S4	View Answer on Stackoverflow

Python PIL has no attribute 'Image'

Python Problem Overview

Python Solutions

Solution 1 - Python

Solution 2 - Python

Solution 3 - Python

Asynchronous constructor

Differentiate between function overloading and function overriding

Attributions