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Is it fine to have foreign key as primary key?
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134
Foreign keys are almost always "Allow Duplicates," which would make them unsuitable as Primary...
what is faster: in_array or isset? [closed]
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119
The answers so far are spot-on. Using isset in this case is faster because
It uses an O(1) h...
Is there a way to pass optional parameters to a function?
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115
The Python 2 documentation, 7.6. Function definitions gives you a couple of ways to detect whe...
R programming: How do I get Euler's number?
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150
The R expression
exp(1)
represents e, and
exp(2)
represents e^2.
This works because exp...
Concatenate two slices in Go
I'm trying to combine the slice [1, 2] and the slice [3, 4] . How can I do this in Go?
7 Answers
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Paperclip::Errors::MissingRequiredValidatorError with Rails 4
...line to your Post model, after specifying has_attached_file :image
Option 1: Validate content type
validates_attachment_content_type :image, :content_type => ["image/jpg", "image/jpeg", "image/png", "image/gif"]
-OR- another way
validates_attachment :image, content_type: { content_type: ["im...
How to backup a local Git repository?
...thub.
#!/usr/bin/env ruby
#
# For documentation please sea man git-backup(1)
#
# TODO:
# - make it a class rather than a function
# - check the standard format of git warnings to be conform
# - do better checking for git repo than calling git status
# - if multiple entries found in config file, spe...
Is git's semi-secret empty tree object reliable, and why is there not a symbolic name for it?
Git has a well-known, or at least sort-of-well-known, empty tree whose SHA1 is:
3 Answers
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Python's json module, converts int dictionary keys to strings
... for the given language, are strings (or "scalars" in Perl). In perl $foo{1}, $foo{1.0}, and $foo{"1"} are all references to the same mapping in %foo --- the key is evaluated as a scalar!
JSON started as a Javascript serialization technology. (JSON stands for JavaScript Object Notation.) Naturall...