Change all urllib2 refs to the Py3-compatible version

source/astropy-UVES/UVES.rst

@@ -25,9 +25,10 @@ Please download this
 the content, either by clicking on the link or by executing this
 python code::
 
-    import urllib2, tarfile
+    from astropy.extern.six.moves.urllib import request
+    import tarfile
     url = 'http://python4astronomers.github.io/_downloads/astropy_UVES.tar.gz'
-    tarfile.open(fileobj=urllib2.urlopen(url), mode='r|*').extractall()
+    tarfile.open(fileobj=request.urlopen(url), mode='r|*').extractall()
     cd UVES
     ls
 

source/astropy/astropy.rst

@@ -32,9 +32,10 @@ Please download this
 the content, either by clicking on the link or by executing this
 python code::
 
-    import urllib2, tarfile
+    from astropy.extern.six.moves.urllib import request
+    import tarfile
     url = 'http://python4astronomers.github.io/_downloads/astropy_examples.tar'
-    tarfile.open(fileobj=urllib2.urlopen(url), mode='r|').extractall()
+    tarfile.open(fileobj=request.urlopen(url), mode='r|').extractall()
     cd data
     ls
 

source/core/numpy_scipy.rst

@@ -52,9 +52,10 @@ Now start IPython ("ipython --matplotlib") or use your existing session and ente
   import numpy as np
   import matplotlib.pyplot as plt
 
-  import urllib2, tarfile
+  from astropy.extern.six.moves.urllib import request
+  import tarfile
   url = 'http://python4astronomers.github.com/core/core_examples.tar'
-  tarfile.open(fileobj=urllib2.urlopen(url), mode='r|').extractall()
+  tarfile.open(fileobj=request.urlopen(url), mode='r|').extractall()
   cd py4ast/core
   ls
 
@@ -63,15 +64,15 @@ Leave this IPython session open for the rest of the workshop.
 .. admonition:: Exercise (for the interested reader): How did that code above work?
 
    Explain what's happening in each part of the previous code snippet to grab
-   the file at a URL and untar it.  Google on "python urllib2" and "python
+   the file at a URL and untar it.  Google on "python3 urllib" and "python
    tarfile" to find the relevant module docs.  Figure out how you would
    use the ``tarfile`` module to create a tarfile.
 
 .. raw:: html
 
    <p class="flip0">Click to Show/Hide Solution</p> <div class="panel0">
 
-- ``urllib2.urlopen(url)`` opens the URL as a streaming file-like object
+- ``urllib.request.urlopen(url)`` opens the URL as a streaming file-like object
 - ``mode='r|' means ``tarfile`` is expecting a streaming file-like object
   with no ability to seek in the file
 - ``tarfile.open(..).extractall`` then extracts the tar archive
@@ -579,7 +580,7 @@ image which includes the source region.
 
 Let's tackle a simpler problem first and fit the background for a single column::
 
-  x = append(np.arange(10, 200), np.arange(300, 480))  # Background rows
+  x = np.append(np.arange(10, 200), np.arange(300, 480))  # Background rows
   y = img_cr[x, 10]         # Background rows of column 10 of cleaned image
   plt.figure()
   plt.plot(x, y)

source/files/asciifiles.rst

@@ -28,9 +28,9 @@ Do the usual imports of numpy and matplotlib::
 
 If you have trouble downloading the file, then from within IPython enter::
 
-    import urllib2
+    from astropy.extern.six.moves.urllib import request
     url = 'http://python4astronomers.github.com/_downloads/data.txt'
-    open('data.txt', 'wb').write(urllib2.urlopen(url).read())
+    open('data.txt', 'wb').write(request.urlopen(url).read())
     ls
 
 Now let's try and get the contents of the file into IPython. We start off by creating a file object::
@@ -516,9 +516,9 @@ rewrite the same code every time when it is already done!).  Instead just use `a
     You'll
    want to start with::
 
-     import urllib2
+     from astropy.extern.six.moves.urllib import request
      from astropy.io import ascii
-     html = urllib2.urlopen('http://hea-www.harvard.edu/XJET/').read()  # Get web page as string
+     html = request.urlopen('http://hea-www.harvard.edu/XJET/').read()  # Get web page as string
      table1 = html2tsv(html, 0)   # Parse the first table in the web page
      table2 = html2tsv(html, 1)   # Parse the second table
      table3 = html2tsv(html, 2)   # Parse the third table

source/files/binaryfiles.rst

@@ -20,9 +20,10 @@ astropy.io.fits
 
     Use the following code to download a FITS file for this exercise::
         
-        import urllib2, tarfile
+        from astropy.extern.six.moves.urllib import request
+        import tarfile
         url = 'http://python4astronomers.github.com/core/core_examples.tar'
-        tarfile.open(fileobj=urllib2.urlopen(url), mode='r|').extractall()
+        tarfile.open(fileobj=request.urlopen(url), mode='r|').extractall()
         cd py4ast/core
         ls
 
@@ -65,9 +66,9 @@ IDL is still a very common tool in astronomy. While IDL packages exist to read a
 Here is an examplary ``.sav`` :download:`file <../downloads/myidlfile.sav>`. 
 If you have trouble downloading the file, then use IPython::
 
-    import urllib2
+    from astropy.extern.six.moves.urllib import request
     url = 'http://python4astronomers.github.com/_downloads/myidlfile.sav'
-    open('myidlfile.sav', 'wb').write(urllib2.urlopen(url).read())
+    open('myidlfile.sav', 'wb').write(request.urlopen(url).read())
     ls
 
 

source/files/summary.rst

@@ -38,9 +38,10 @@ Here are some hints:
 
     Download the example :download:`data <../downloads/files-excercise.tar.gz>`::
 
-        import urllib2, tarfile
+        from astropy.extern.six.moves.urllib import request
+        import tarfile
         url = 'http://python4astronomers.github.com/_downloads/files-excercise.tar.gz'
-        tarfile.open(fileobj=urllib2.urlopen(url), mode='r|gz').extractall()
+        tarfile.open(fileobj=request.urlopen(url), mode='r|gz').extractall()
         cd files
         ls
 

source/fitting/image.rst

@@ -17,9 +17,9 @@ Do the usual imports of numpy and matplotlib::
 If you have trouble accessing the image you can download it straight away using
 Python::
 
-  import urllib2
+  from astropy.extern.six.moves.urllib import request
   url = "http://python4astronomers.github.com/_downloads/image2.fits"
-  open("image2.fits", "wb").write(urllib2.urlopen(url).read())
+  open("image2.fits", "wb").write(request.urlopen(url).read())
   ls
 
 Here we eschew the advice of keeping modules separate and load the

source/fitting/low-level.rst

@@ -20,9 +20,9 @@ and start IPython along with the standard imports::
 If you have trouble accessing the spectrum you can download it straight away
 using Python::
 
-  import urllib2
+  from astropy.extern.six.moves.urllib import request
   url = 'http://python4astronomers.github.com/_downloads/3c273.fits'
-  open('3c273.fits', 'wb').write(urllib2.urlopen(url).read())
+  open('3c273.fits', 'wb').write(request.urlopen(url).read())
   %ls
 
 Import a few Sherpa classes needed to characterize a fit::

source/fitting/sherpa.rst

@@ -60,9 +60,10 @@ then go to the py4ast/core directory, otherwise ::
 
   $ ipython --matplotlib
 
-  import urllib2, tarfile
+  from astropy.extern.six.moves.urllib import request
+  import tarfile
   url = 'http://python4astronomers.github.com/core/core_examples.tar'
-  tarfile.open(fileobj=urllib2.urlopen(url), mode='r|').extractall()
+  tarfile.open(fileobj=request.urlopen(url), mode='r|').extractall()
   cd py4ast/core
 
 Now we load the Sherpa UI module and other requirements::

source/fitting/spectrum.rst

@@ -15,9 +15,9 @@ and start IPython ::
 If you have trouble accessing the spectrum you can download it straight away
 using Python  ::
 
-  import urllib2
+  from astropy.extern.six.moves.urllib import request
   url = 'http://python4astronomers.github.com/_downloads/3c273.fits'
-  open('3c273.fits', 'wb').write(urllib2.urlopen(url).read())
+  open('3c273.fits', 'wb').write(request.urlopen(url).read())
 
 We also need to load in Sherpa ::
 

source/plotting/aplpy.rst

@@ -38,9 +38,10 @@ Start off by downloading :download:`this tar file <../downloads/APLpy-example.ta
 
 If you have trouble downloading the file, then within your IPython session enter::
 
-    import urllib2, tarfile
+    from astropy.extern.six.moves.urllib import request
+    import tarfile
     url = 'http://python4astronomers.github.com/_downloads/APLpy-example.tar'
-    tarfile.open(fileobj=urllib2.urlopen(url), mode='r|').extractall()
+    tarfile.open(fileobj=request.urlopen(url), mode='r|').extractall()
     cd APLpy-example
     ls
 
@@ -137,8 +138,9 @@ To show the y-axis labels in dd:mm format::
 
     If you have trouble downloading the file, then within your IPython session enter::
 
-        import urllib2, tarfile
+        from astropy.extern.six.moves.urllib import request
+        import tarfile
         url = 'http://python4astronomers.github.com/_downloads/m82_wise.tar'
-        tarfile.open(fileobj=urllib2.urlopen(url), mode='r|').extractall()
+        tarfile.open(fileobj=request.urlopen(url), mode='r|').extractall()
         cd m82_wise
         ls

source/plotting/matplotlib.rst

@@ -346,7 +346,7 @@ somewhat cryptic messsage above. For new users it would be nice if it
 said "hold on, size isn't callable", but then this would inhibit
 useful - if complex - statements such as::
 
-    tarfile.open(fileobj=urllib2.urlopen(url), mode='r|').extractall()
+    tarfile.open(fileobj=request.urlopen(url), mode='r|').extractall()
 
 Controlling line properties
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^