some ipython magic commands

10-magics.py

from __future__ import print_function

def loadnpz_impl(self, params=''):
    """Load a npz file into user namespace.

    %loadnpz <filename.npz>
    """
    import numpy as np
    ip = get_ipython()

    args = params.split()
    if len(args) == 0:
        return
    filename, = args
    ip.push(dict(np.load(filename)), interactive=True)


def loadmat_impl(self, params=''):
    """Load a MATLAB file into user namespace.

    %loadmat [-s] <filename.mat>

    The -s option squeezes unit matrix dimensions.
    """
    from scipy.io import loadmat
    ip = get_ipython()

    args = params.split()
    if len(args) == 0:
        return
    if args[0] == '-s':
        squeeze_me = True
        _, filename = args
    else:
        squeeze_me = False
        filename, = args
    ip.push(loadmat(filename, squeeze_me=squeeze_me), interactive=True)

def savemat_impl(self, params=''):
    """Save interactive variables to a MATLAB file.

    %savemat <filename.mat>
            - Saves all interactive variables.
    %savemat <filename.mat> <var1 var2 ...>
            - Saves selected variables var1, var2, etc. only.
    """
    from scipy.io import savemat
    ip = get_ipython()

    args = params.split()
    if len(args) == 0:
        return
    filename, vars = args[0], args[1:]

    if len(vars) == 0:
        sel = dict((k, ip.user_ns[k]) for k in ip.magic('%who_ls'))
        print("Saving variables:", list(sel.keys()))
        savemat(filename, sel)
    else:
        sel = dict((k, ip.user_ns[k]) for k in vars)
        print("Saving variables:", list(sel.keys()))
        savemat(filename, sel)

def imshow_impl(self, params=''):
    """Shows given image in matplotlib.

    %imshow [options] name ...

    -t <title>  Set title of all figures. The default title
                is the name of the image.
    -c <cmap>   Set colormap of all figures (e.g. gray).

    """
    ip = get_ipython()
    opts, args = ip.parse_options(params, 'c:t:')
    names = args.split()

    cmap = cm.jet
    if 'c' in opts:
        cmap = cm.get_cmap(name=opts.c)
        if cmap is None:
            print("invalid colormap:", opts.c)
            return

    titles = names
    if 't' in opts:
        titles = len(names)*[opts.t]

    for name, tl in zip(names, titles):
        img = np.squeeze(ip.user_ns[name])
        figure()
        imshow(img, interpolation='nearest', cmap=cmap)
        colorbar()
        title(tl)

if __name__ == '__main__':
    ip = get_ipython()
    ip.define_magic('loadmat', loadmat_impl)
    ip.define_magic('loadnpz', loadnpz_impl)
    ip.define_magic('savemat', savemat_impl)
    ip.define_magic('imshow', imshow_impl)

    # clean up ipython's namespace
    del ip, savemat_impl, loadmat_impl, imshow_impl