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How to copy file from HDFS to the local file system
...oop fs -copyToLocal /hdfs/source/path /localfs/destination/path
Point your web browser to HDFS WEBUI(namenode_machine:50070), browse to the file you intend to copy, scroll down the page and click on download the file.
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Scala how can I count the number of occurrences in a list
...", "banana", "apple", "oranges", "oranges")
s.groupBy(identity).mapValues(_.size)
giving a Map with a count for each item in the original sequence:
Map(banana -> 1, oranges -> 3, apple -> 3)
The question asks how to find the count of a specific item. With this approach, the solution w...
Non-alphanumeric list order from os.listdir()
...however you want. Based on what you describe,
sorted(os.listdir(whatever_directory))
Alternatively, you can use the .sort method of a list:
lst = os.listdir(whatever_directory)
lst.sort()
I think should do the trick.
Note that the order that os.listdir gets the filenames is probably complet...
How can I get a list of all functions stored in the database of a particular schema in PostgreSQL?
I want to be able to connect to a PostgreSQL database and find all of the functions for a particular schema.
9 Answers
...
Explicitly select items from a list or tuple
... myBigList[i] for i in [87, 342, 217, 998, 500] ]
20.6 usec: map(myBigList.__getitem__, (87, 342, 217, 998, 500))
22.7 usec: itemgetter(87, 342, 217, 998, 500)(myBigList)
24.6 usec: list( myBigList[i] for i in [87, 342, 217, 998, 500] )
Note that in Python 3, the 1st was changed to be the same as ...
Python argparse: Make at least one argument required
...
args = vars(parser.parse_args())
if not any(args.values()):
parser.error('No arguments provided.')
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How do I vertically align text in a div?
...; vertical-align: middle;">
<div>
everything is vertically centered in modern IE8+ and others.
</div>
</div>
</div>
It is possible to merge hacks for old browsers (Internet Explorer 6/7) into styles with using # to hide styles from newer brows...
How to read a file in reverse order?
...A correct, efficient answer written as a generator.
import os
def reverse_readline(filename, buf_size=8192):
"""A generator that returns the lines of a file in reverse order"""
with open(filename) as fh:
segment = None
offset = 0
fh.seek(0, os.SEEK_END)
file...
How to generate keyboard events in Python?
...om ctypes import wintypes
import time
user32 = ctypes.WinDLL('user32', use_last_error=True)
INPUT_MOUSE = 0
INPUT_KEYBOARD = 1
INPUT_HARDWARE = 2
KEYEVENTF_EXTENDEDKEY = 0x0001
KEYEVENTF_KEYUP = 0x0002
KEYEVENTF_UNICODE = 0x0004
KEYEVENTF_SCANCODE = 0x0008
MAPVK_VK_TO_VSC = 0
# ...
Launching Google Maps Directions via an intent on Android
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Navigation intents seem to be officially supported now: developers.google.com/maps/documentation/android/…
– Sanketh Katta
Feb 15 '15 at 1:59
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