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How to install a gem or update RubyGems if it fails with a permissions error
... using gem install mygem or update RubyGems using gem update --system , and it fails with this error:
27 Answers
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What is the difference between Non-Repeatable Read and Phantom Read?
What is the difference between non-repeatable read and phantom read?
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Should I use pt or px?
What is the difference between pt and px in CSS? Which one should I use and why?
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How to combine multiple conditions to subset a data-frame using “OR”?
... the following syntax before with lot of success when I wanted to use the "AND" condition.
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List comprehension vs map
...re NOT making a lambda for the purpose, but using the same function in map and a listcomp). List comprehensions may be faster in other cases and most (not all) pythonistas consider them more direct and clearer.
An example of the tiny speed advantage of map when using exactly the same function:
$ p...
SQL Server Text type vs. varchar data type [closed]
I have variable length character data and want to store in SQL Server (2005) database. I want to learn some best practices about how to choose TEXT SQL type or choose VARCHAR SQL type, pros and cons in performance/footprint/function.
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How do I use a Boolean in Python?
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Actually Python didn't have a boolean type for a long time (as in old C), and some programmers still use integers instead of booleans.
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Facebook database design?
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Keep a friend table that holds the UserID and then the UserID of the friend (we will call it FriendID). Both columns would be foreign keys back to the Users table.
Somewhat useful example:
Table Name: User
Columns:
UserID PK
EmailAddress
Password
Ge...
Why does jQuery or a DOM method such as getElementById not find the element?
...ers parse HTML documents from top to bottom. Elements are added to the DOM and scripts are (generally) executed as they're encountered. This means that order matters. Typically, scripts can't find elements which appear later in the markup because those elements have yet to be added to the DOM.
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How do I use boolean variables in Perl?
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@BlueWaldo: you can also use cmp and <=> when comparing and assigning the results of the comparison to a scalar. $var = $var1 cmp $var2; 'cmp' and '<=>' (used for numeric comparisons) returns -1, 0, or 1 if left argument is less than, equal to,...