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PostgreSQL: Difference between text and varchar (character varying)
What's the difference between the text data type and the character varying ( varchar ) data types?
9 Answers
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How can I initialize base class member variables in derived class constructor?
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You can't initialize a and b in B because they are not members of B. They are members of A, therefore only A can initialize them. You can make them public, then do assignment in B, but that is not a recommended option since it would destroy encapsulation. Instead, create a constructor in ...
How do I merge changes to a single file, rather than merging commits?
I have two branches (A and B) and I want to merge a single file from branch A with a corresponding single file from Branch B.
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How do I tar a directory of files and folders without including the directory itself?
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cd my_directory/ && tar -zcvf ../my_dir.tgz . && cd -
should do the job in one line. It works well for hidden files as well. "*" doesn't expand hidden files by path name expansion at least in bash. Below is my experiment:
$ mkdir my_director...
Node.js check if file exists
How do i check the existence of a file ?
17 Answers
17
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How to do an INNER JOIN on multiple columns
I'm working on a homework project and I'm supposed to perform a database query which finds flights either by the city name or the airport code, but the flights table only contains the airport codes so if I want to search by city I have to join on the airports table.
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How to capture stdout output from a Python function call?
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Try this context manager:
from io import StringIO
import sys
class Capturing(list):
def __enter__(self):
self._stdout = sys.stdout
sys.stdout = self._stringio = StringIO()
return self
def __exit__(self, *args):
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Display number with leading zeros
...(and Python 3) you can do:
print "%02d" % (1,)
Basically % is like printf or sprintf (see docs).
For Python 3.+, the same behavior can also be achieved with format:
print("{:02d}".format(1))
For Python 3.6+ the same behavior can be achieved with f-strings:
print(f"{1:02d}")
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Use find command but exclude files in two directories
I want to find files that end with _peaks.bed , but exclude files in the tmp and scripts folders.
6 Answers
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How to convert an int to a hex string?
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You are looking for the chr function.
You seem to be mixing decimal representations of integers and hex representations of integers, so it's not entirely clear what you need. Based on the description you gave, I think one of these snippets ...