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Can the Unix list command 'ls' output numerical chmod permissions?
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For creating it as an alias (example below: 'cls' command), use: alias cls="ls -l | awk '{k=0;for(i=0;i<=8;i++)k+=((substr(\$1,i+2,1)~/[rwx]/)*2^(8-i));if(k)printf(\"%0o \",k);print}'"
– danger89
Mar 6 '14 at 16:15
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What's the Hi/Lo algorithm?
...dea is that you have two numbers to make up a primary key- a "high" number and a "low" number. A client can basically increment the "high" sequence, knowing that it can then safely generate keys from the entire range of the previous "high" value with the variety of "low" values.
For instance, suppo...
How do I check that a number is float or integer?
...0;
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Update 2019
5 years after this answer was written, a solution was standardized in ECMA Script 2015. That solution is covered in this answer.
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What is the purpose of base 64 encoding and why it used in HTTP Basic Authentication?
...pedia page for HTTP Basic Authentication:
While encoding the user name and password with the Base64 algorithm typically makes them unreadable by the naked eye, they are as easily decoded as they are encoded. Security is not the intent of the encoding step. Rather, the intent of the encoding is t...
What is the difference between .*? and .* regular expressions?
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It is the difference between greedy and non-greedy quantifiers.
Consider the input 101000000000100.
Using 1.*1, * is greedy - it will match all the way to the end, and then backtrack until it can match 1, leaving you with 1010000000001.
.*? is non-greedy. * w...
Finding duplicate values in a SQL table
...T(*) > 1
Simply group on both of the columns.
Note: the older ANSI standard is to have all non-aggregated columns in the GROUP BY but this has changed with the idea of "functional dependency":
In relational database theory, a functional dependency is a constraint between two sets of attrib...
What is the intent of the methods getItem and getItemId in the Android class BaseAdapter?
I'm curious about the purpose of the methods getItem and getItemId in the class Adapter in the Android SDK.
6 Answers
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Change column type from string to float in Pandas
I want to convert a table, represented as a list of lists, into a Pandas DataFrame . As an extremely simplified example:
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How to add calendar events in Android?
I'm just getting up to speed on Android, and today in a project meeting someone said that Android has no native calendar app so users just use whatever calendar app they like.
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Why do access tokens expire?
I am just getting started working with Google API and OAuth2. When the client authorizes my app I am given a "refresh token" and a short lived "access token". Now every time the access token expires, I can POST my refresh token to Google and they will give me a new access token.
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