Uploading files using Browse Button in Jupyter and Using/Saving them

Question

I came across this snippet for uploading files in Jupyter however I don't know how to save this file on the machine that executes the code or how to show the first 5 lines of the uploaded file. Basically I am looking for proper commands for accessing the file after it has been uploaded:

import io
from IPython.display import display
import fileupload

def _upload():

    _upload_widget = fileupload.FileUploadWidget()

    def _cb(change):
        decoded = io.StringIO(change['owner'].data.decode('utf-8'))
        filename = change['owner'].filename
        print('Uploaded `{}` ({:.2f} kB)'.format(
            filename, len(decoded.read()) / 2 **10))

    _upload_widget.observe(_cb, names='data')
    display(_upload_widget)

_upload()

Answer 1

_cb is called when the upload finishes. As described in the comment above, you can write to a file there, or store it in a variable. For example:

from IPython.display import display
import fileupload

uploader = fileupload.FileUploadWidget()

def _handle_upload(change):
    w = change['owner']
    with open(w.filename, 'wb') as f:
        f.write(w.data)
    print('Uploaded `{}` ({:.2f} kB)'.format(
        w.filename, len(w.data) / 2**10))

uploader.observe(_handle_upload, names='data')

display(uploader)

After the upload has finished, you can access the filename as:

uploader.filename

Answer 2

I am working on ML with Jupyter notebook, and I was looking for a solution to select the local files containing the datasets by browsing amongst the local file system. Although, the question here refers more to uploading than selecting a file. I am putting here a snippet that I found here because when I was looking for a solution for my particular case, the result of the search took me several times to here.

import os
import ipywidgets as widgets

class FileBrowser(object):
    def __init__(self):
        self.path = os.getcwd()
        self._update_files()

    def _update_files(self):
        self.files = list()
        self.dirs = list()
        if(os.path.isdir(self.path)):
            for f in os.listdir(self.path):
                ff = os.path.join(self.path, f)
                if os.path.isdir(ff):
                    self.dirs.append(f)
                else:
                    self.files.append(f)

    def widget(self):
        box = widgets.VBox()
        self._update(box)
        return box

    def _update(self, box):

        def on_click(b):
            if b.description == '..':
                self.path = os.path.split(self.path)[0]
            else:
                self.path = os.path.join(self.path, b.description)
            self._update_files()
            self._update(box)

        buttons = []
        if self.files:
            button = widgets.Button(description='..', background_color='#d0d0ff')
            button.on_click(on_click)
            buttons.append(button)
        for f in self.dirs:
            button = widgets.Button(description=f, background_color='#d0d0ff')
            button.on_click(on_click)
            buttons.append(button)
        for f in self.files:
            button = widgets.Button(description=f)
            button.on_click(on_click)
            buttons.append(button)
        box.children = tuple([widgets.HTML("<h2>%s</h2>" % (self.path,))] + buttons)

And to use it:

f = FileBrowser()
f.widget()
#   <interact with widget, select a path>
# in a separate cell:
f.path # returns the selected path