Tarik - Row Coding - Page 17589 of 18124

Can dpkg verify files from an installed package?

I don’t thinks so, in Ubuntu md5 checksums are only stored for certain files. For any given package the list of files that have checksums can be found in /var/lib/dpkg/info/<package>.md5sums e.g /var/lib/dpkg/info/openssh-server.md5sums These generally don’t contain a complete list of the files that have been installed by a package e.g. openssh-server.md5sums bb5096cf79a43b479a179c770eae86d8 usr/lib/openssh/sftp-server 42da5b1c2de18ec8ef4f20079a601f28 usr/sbin/sshd …

Interface defining a constructor signature?

by Tarik

You can’t. It’s occasionally a pain, but you wouldn’t be able to call it using normal techniques anyway. In a blog post I’ve suggested static interfaces which would only be usable in generic type constraints – but could be really handy, IMO. One point about if you could define a constructor within an interface, you’d …

Should I use ‘border: none’ or ‘border: 0’?

by Tarik

Both are valid. It’s your choice. I prefer border:0 because it’s shorter; I find that easier to read. You may find none more legible. We live in a world of very capable CSS post-processors so I’d recommend you use whatever you prefer and then run it through a “compressor”. There’s no holy war worth fighting …

C-like structures in Python

by Tarik

Update: Data Classes With the introduction of Data Classes in Python 3.7 we get very close. The following example is similar to the NamedTuple example below, but the resulting object is mutable and it allows for default values. from dataclasses import dataclass @dataclass class Point: x: float y: float z: float = 0.0 p = …

MySql export schema without data

by Tarik

You can do with the –no-data option with mysqldump command mysqldump -h yourhostnameorIP -u root -p –no-data dbname > schema.sql

How can I update the current line in a C# Windows Console App?

by Tarik

If you print only “\r” to the console the cursor goes back to the beginning of the current line and then you can rewrite it. This should do the trick: for(int i = 0; i < 100; ++i) { Console.Write(“\r{0}% “, i); } Notice the few spaces after the number to make sure that whatever …

Java 8 Distinct by property

by Tarik

Consider distinct to be a stateful filter. Here is a function that returns a predicate that maintains state about what it’s seen previously, and that returns whether the given element was seen for the first time: public static <T> Predicate<T> distinctByKey(Function<? super T, ?> keyExtractor) { Set<Object> seen = ConcurrentHashMap.newKeySet(); return t -> seen.add(keyExtractor.apply(t)); } …

How to interpolate variables in strings in JavaScript, without concatenation?

by Tarik

You can take advantage of Template Literals and use this syntax: `String text ${expression}` Template literals are enclosed by the back-tick (` `) (grave accent) instead of double or single quotes. This feature has been introduced in ES2015 (ES6). Example var a = 5; var b = 10; console.log(`Fifteen is ${a + b}.`); // “Fifteen …

Postgres could not connect to server

by Tarik

Had a similar problem; a pid file was blocking postgres from starting up. To fix it: $ rm /usr/local/var/postgres/postmaster.pid $ brew services restart postgresql and then all is well. UPDATE: For Apple M1 (Big Sur) users, do this instead: $ rm /opt/homebrew/var/postgres/postmaster.pid $ brew services restart postgresql

How to sum array of numbers in Ruby?

by Tarik

For ruby >= 2.4 you can use sum: array.sum For ruby < 2.4 you can use inject: array.inject(0, :+) Note: the 0 base case is needed otherwise nil will be returned on empty arrays: > [].inject(:+) nil > [].inject(0, :+) 0