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Code Golf: Lasers

...amp;!ge,$s=$r+=99for<>;%d='>.^1<2v3'=~/./g;($r)=grep$d|=$d{$t{$_}},%t; {$_=$t{$r+=(1,-99,-1,99)[$d^=3*/\\/+m</>]};/[\/\\ ]/&&redo}die/x/?true:false,$/ The first line loads the input into %t, a table of the board where $t{99*i+j} holds the character at row i,column j. Then...
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Postgres and Indexes on Foreign Keys and Primary Keys

...n ('pg_catalog', 'pg_toast') and pg_catalog.pg_table_is_visible(c.oid) order by n.nspname ,t.relname ,c.relname If you want to delve further (such as columns and ordering), you need to look at pg_catalog.pg_index. Using psql -E [dbname] comes in handy for figuring out how to query...
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What is the difference between a field and a property?

...It is private to your class and stores the actual data. private string _myField; // this is a property. When accessed it uses the underlying field, // but only exposes the contract, which will not be affected by the underlying field public string MyProperty { get ...
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Elegant way to invert a map in Scala

... Assuming values are unique, this works: (Map() ++ origMap.map(_.swap)) On Scala 2.8, however, it's easier: origMap.map(_.swap) Being able to do that is part of the reason why Scala 2.8 has a new collection library. ...
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Why can't I use a list as a dict key in python?

...le, it'll work correctly with classes that have a custom comparison method __eq__. But if you convert them to strings, everything is compared by its string representation. – Aran-Fey May 20 '18 at 12:50 ...
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Drop unused factor levels in a subsetted data frame

... Also: this method does preserve the ordering of the variable. – webelo Jul 1 '16 at 0:36  |  show 1 mor...
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ORA-00979 not a group by expression

... No, you do not need to put them in your order by clause – Xaisoft Oct 5 '09 at 15:10 3 ...
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How do I spool to a CSV formatted file using SQLPLUS?

... numbers (avoid scientific notation on IDs) spool myfile.csv select table_name, tablespace_name from all_tables where owner = 'SYS' and tablespace_name is not null; Output will be like: TABLE_PRIVILEGE_MAP ,SYSTEM SYSTEM_PRIVILEGE_MAP ,S...
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What is the fastest/most efficient way to find the highest set bit (msb) in an integer in C?

... GCC has: -- Built-in Function: int __builtin_clz (unsigned int x) Returns the number of leading 0-bits in X, starting at the most significant bit position. If X is 0, the result is undefined. -- Built-in Function: int __builtin_clzl (unsigned long...
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How to download a file from a URL in C#?

...ethod also supports local files as 1st parameter – oo_dev Aug 22 '17 at 8:35 The MSDN doc did mention to use HttpClien...