You can check, if an index with a given name exists with this statement. If your index name is some_table_some_field_idx SELECT count(*) > 0 FROM pg_class c WHERE c.relname=”some_table_some_field_idx” AND c.relkind = ‘i’; Starting from Postgres 9.5 you can even use CREATE INDEX IF NOT EXISTS
If the input sequence is sorted, you could use sets here. Take the start and end values from the input list: def missing_elements(L): start, end = L[0], L[-1] return sorted(set(range(start, end + 1)).difference(L)) This assumes Python 3; for Python 2, use xrange() to avoid building a list first. The sorted() call is optional; without it … Read more
Please don’t remove the .git/svn folder to fix this. It requires you to rebuild everything, it is annoying, it will take awhile (for the size of my repo several hours) and it is NOT NECESSARY. I found the right answer here and I’ve included it below. From the link: Inside the .git directory run the … Read more
Although a little more convoluted than I would like, another solution is to use the Chars iterator and its position() function: “Program”.chars().position(|c| c == ‘g’).unwrap() find used in the accepted solution returns the byte offset and not necessarily the index of the character. It works fine with basic ASCII strings, such as the one in … Read more
Edit your apache2 configuration file which normally is on the dir: “/etc/apache2/httpd.conf”. Add the following or edit if your already have some configurations for the default web server dir (/var/www): <Directory /var/www> Options -Indexes AllowOverride All Order allow,deny Allow from all </Directory> This will disable the indexing to all the public directories.
As you can see in the error message – “The maximum column size is 767 bytes”, if you want to create an index on it. A VARCHAR(255) column can take up to 765 (255*3) bytes using utf8 and 1020 (255*4) bytes using utf8mb4. This is because in MySQL utf8 takes up to 3 bytes and … Read more
Your summary isn’t completely correct, you already did tests with differently sized arrays but one thing that you didn’t do was to change the number of elements indexed. I restricted it to pure indexing and omitted take (which effectively is integer array indexing) and compress and extract (because these are effectively boolean array indexing). The … Read more
If you relax the constraint that the Position column must contain integers from 1 to N and instead allow it to contain any numbers then you can do both searches and updates efficiently. You can insert an item between two other items with position A and B by calculating the average (A + B) DIV … Read more
That’s because a SortedSet has the semantics of a set and is not a List-like construct. Consequently, it does not implement IList (which give you the ability to address items by index via the Item property). As noted by @DavidRR, you could use the Linq extension method Enumerable.ElementAt(). However, since the backing store of a … Read more
Yes, at least one case is considerably slower. If you only define the following index: ALTER TABLE … ADD INDEX (a, b); … then the query SELECT * FROM … WHERE B = 1; will not use that index. When you create an index with a composite key, the order of the columns of the … Read more