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How to print a string in fixed width?
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EDIT 2013-12-11 - This answer is very old. It is still valid and correct, but people looking at this should prefer the new format syntax.
You can use string formatting like this:
>>> print '%5s' % 'aa'
aa
>>> print '%5s' % 'aaa'
aaa
>>> print '%5s' % 'aaaa'...
List of lists changes reflected across sublists unexpectedly
... that you create a new list at each position. One way to do it is
[[1]*4 for _ in range(3)]
which will reevaluate [1]*4 each time instead of evaluating it once and making 3 references to 1 list.
You might wonder why * can't make independent objects the way the list comprehension does. That's b...
Representing null in JSON
What is the preferred method for returning null values in JSON? Is there a different preference for primitives?
7 Answers
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Git: How to remove file from index without deleting files from any repository
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I do not think a Git commit can record an intention like “stop tracking this file, but do not delete it”.
Enacting such an intention will require intervention outside Git in any repositories that merge (or rebase onto) a commit that deletes the file.
S...
Benefits of using the conditional ?: (ternary) operator
What are the benefits and drawbacks of the ?: operator as opposed to the standard if-else statement. The obvious ones being:
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Assigning default values to shell variables with a single command in bash
...hat you posted, actually:
FOO=${VARIABLE:-default} # If variable not set or null, use default.
Or, which will assign default to VARIABLE as well:
FOO=${VARIABLE:=default} # If variable not set or null, set it to default.
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How to implement a many-to-many relationship in PostgreSQL?
I believe the title is self-explanatory. How do you create the table structure in PostgreSQL to make a many-to-many relationship.
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Sorting a vector of custom objects
How does one go about sorting a vector containing custom (i.e. user defined) objects.
Probably, standard STL algorithm sort along with a predicate (a function or a function object) which would operate on one of the fields (as a key for sorting) in the custom object should be used.
Am I on the ...
Forward declaring an enum in C++
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The reason the enum can't be forward declared is that without knowing the values, the compiler can't know the storage required for the enum variable. C++ Compiler's are allowed to specify the actual storage space based on the size necessary to contain al...
NoSQL (MongoDB) vs Lucene (or Solr) as your database
...e my lessons learned:
You can easily use Lucene/Solr in lieu of MongoDB for pretty much all situations, but not vice versa. Grant Ingersoll's post sums it up here.
MongoDB etc. seem to serve a purpose where there is no requirement of searching and/or faceting. It appears to be a simpler and arguab...