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Evaluating a mathematical expression in a string
...ppend(toks[0])
def pushUMinus(self, strg, loc, toks):
if toks and toks[0] == '-':
self.exprStack.append('unary -')
def __init__(self):
"""
expop :: '^'
multop :: '*' | '/'
addop :: '+' | '-'
integer :: ['+' | '-'] '0'..'9'+
...
How to efficiently build a tree from a flat structure?
I have a bunch of objects in a flat structure. These objects have an ID and a ParentID property so they can be arranged in trees. They are in no particular order.
Each ParentID property does not necessarily matches with an ID in the structure. Therefore their could be several trees emerging ...
Updating MySQL primary key
...delete u from user_interactions u, fixit
where fixit.user_2 = u.user_2
and fixit.user_1 = u.user_1
and fixit.type = u.type
and fixit.timestamp != u.timestamp;
alter table user_interactions add primary key (user_2, user_1, type );
unlock tables;
The lock should stop further updates comi...
Why are there two kinds of functions in Elixir?
I'm learning Elixir and wonder why it has two types of function definitions:
8 Answers
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C: differences between char pointer and array [duplicate]
...ent scope's stack space, it is unspecified exactly where it will be stored and should not be modified.
Edit: As pointed out by Mark, GMan, and Pavel, there is also a difference when the address-of operator is used on either of these variables. For instance, &pmessage returns a pointer of type ...
Install parent POM without building Child modules
...
Use the '-N' option in the mvn command.
From mvn -h:
-N,--non-recursive Do not recurse into sub-projects
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Convert PHP closing tag into comment
...enate the string from two pieces. This way, the closing tag is cut in two, and is not a valid closing tag anymore. '?>' --> '?'.'>'
In your code:
$string = preg_replace('#<br\s*/?'.'>(?:\s*<br\s*/?'.'>)+#i', '<br />', $string);
This will make // comments work.
For /*...
mysql_config not found when installing mysqldb python interface
...
mySQLdb is a python interface for mysql, but it is not mysql itself. And apparently mySQLdb needs the command 'mysql_config', so you need to install that first.
Can you confirm that you did or did not install mysql itself, by running "mysql" from the shell? That should give you a response oth...
What __init__ and self do on Python?
I'm learning the Python programming language and I've came across something I don't fully understand.
18 Answers
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How do I access the command history from IDLE?
On bash or Window's Command Prompt, we can press the up arrow on keyboard to get the last command, and edit it, and press ENTER again to see the result.
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