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How to set child process' environment variable in Makefile
...
I have GNU make 3.81, and all: <\n\t>export PROJ_ROOT=$(CURDIR)<\n\t>echo $(PROJ_ROOT)<\n> outputs the correct expansion for the first row, but only echo for the second one. PROJ_ROOT is not set after running make. Spaces around = gi...
What are the differences between json and simplejson Python modules?
...ossible.
A good practice, in my opinion, is to use one or the other as a fallback.
try:
import simplejson as json
except ImportError:
import json
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How can I get the MAC and the IP address of a connected client in PHP?
... address, you could parse the output of netstat -ie in Linux, or ipconfig /all in Windows.
Client IP address
You can get the client IP from $_SERVER['REMOTE_ADDR']
Client MAC address
The client MAC address will not be available to you except in one special circumstance: if the client is on the s...
How do I list all tables in a schema in Oracle SQL?
How do i list all tables in a schema in Oracle SQL?
14 Answers
14
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Use cases for the 'setdefault' dict method
...e case: Grouping items (in unsorted data, else use itertools.groupby)
# really verbose
new = {}
for (key, value) in data:
if key in new:
new[key].append( value )
else:
new[key] = [value]
# easy with setdefault
new = {}
for (key, value) in data:
group = new.setdefault(k...
What is the best method to merge two PHP objects?
...bj_merged = (object) array_merge((array) $obj1, (array) $obj2);
This actually also works when objects have methods. (tested with PHP 5.3 and 5.6)
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Representing graphs (data structure) in Python
...f._graph[node2].add(node1)
def remove(self, node):
""" Remove all references to node """
for n, cxns in self._graph.items(): # python3: items(); python2: iteritems()
try:
cxns.remove(node)
except KeyError:
pass
tr...
Android: upgrading DB version and adding new table
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1. About onCreate() and onUpgrade()
onCreate(..) is called whenever the app is freshly installed. onUpgrade is called whenever the app is upgraded and launched and the database version is not the same.
2. Incrementing the db version
You need a constructor like:
MyOpenHelp...
When I catch an exception, how do I get the type, file, and line number?
...Error:
print(traceback.format_exc())
Output
Traceback (most recent call last):
File "/path/to/file.py", line 51, in <module>
print(4/0)
ZeroDivisionError: division by zero
Process finished with exit code 0
...
What's the _ underscore representative of in Swift References?
...ng, s2: String) -> String {
return s1 + s2;
}
}
When you call foo(), it is called like bar.foo("Hello", s2: "World").
But, you can override this behavior by using _ in front of s2 where it's declared.
func foo(s1: String, _ s2: String) -> String{
return s1 + s2;
}
Then, w...