Tutorial by Examples: g

CROSS APPLY enables you to "join" rows from a table with dynamically generated rows returned by some table-value function. Imagine that you have a Company table with a column that contains an array of products (ProductList column), and a function that parse these values and returns a set ...

This section describes some basic DDL (="Data Definition Language") commands to create a database, a table within a database, a view and finally a stored procedure. Create Database The following SQL command creates a new database Northwind on the current server, using pathC:\Program Fi...

Bashdb is a utility that is similar to gdb, in that you can do things like set breakpoints at a line or at a function, print content of variables, you can restart script execution and more. You can normally install it via your package manager, for example on Fedora: sudo dnf install bashdb Or ...

It is well known that you cannot use the same file for input and ouput in the same command. For instance, $ cat header.txt body.txt >body.txt doesn’t do what you want. By the time cat reads body.txt, it has already been truncated by the redirection and it is empty. The final result will be th...

On Julia, you can define more than one method for each function. Suppose we define three methods of the same function: foo(x) = 1 foo(x::Number) = 2 foo(x::Int) = 3 When deciding what method to use (called dispatch), Julia chooses the more specific method that matches the types of the argument...

JSON is a popular data interchange format. The most popular JSON library for Julia is JSON.jl. To install this package, use the package manager: julia> Pkg.add("JSON") The next step is to test whether the package is working on your machine: julia> Pkg.test("JSON") I...

JSON that has been encoded as a string can easily be parsed into a standard Julia type: julia> using JSON julia> JSON.parse("""{ "this": ["is", "json"], "numbers": [85, 16, 12.0], "and": [t...

The JSON.json function serializes a Julia object into a Julia String containing JSON: julia> using JSON julia> JSON.json(Dict(:a => :b, :c => [1, 2, 3.0], :d => nothing)) "{\"c\":[1.0,2.0,3.0],\"a\":\"b\",\"d\":null}" julia>...

You can list all files ignored by git in current directory with command: git status --ignored So if we have repository structure like this: .git .gitignore ./example_1 ./dir/example_2 ./example_2 ...and .gitignore file containing: example_2 ...than result of the command will be: $ g...

ORDER BY x ASC -- same as default ORDER BY x DESC -- highest to lowest ORDER BY lastname, firstname -- typical name sorting; using two columns ORDER BY submit_date DESC -- latest first ORDER BY submit_date DESC, id ASC -- latest first, but fully specifying order. ASC = ASCENDING, DESC ...

Memcache is a distributed object caching system and uses key-value for storing small data. Before you start calling Memcache code into PHP, you need to make sure that it is installed. That can be done using class_exists method in php. Once it is validated that the module is installed, you start with...

See what, when and why if you don't know about the affiliation of IFS to word splitting let's set the IFS to space character only: set -x var='I am a multiline string' IFS=' ' fun() { echo "-$1-" echo "*$2*" echo ".$3." } fun $var This time wo...

$ a='I am a string with spaces' $ [ $a = $a ] || echo "didn't match" bash: [: too many arguments didn't match [ $a = $a ] was interpreted as [ I am a string with spaces = I am a string with spaces ]. [ is the test command for which I am a string with spaces is not a single argument...

There are some cases where word splitting can be useful: Filling up array: arr=($(grep -o '[0-9]\+' file)) This will fill up arr with all numeric values found in file Looping through space separated words: words='foo bar baz' for w in $words;do echo "W: $w" done Output...

while IFS= read -r line; do echo "$line" done <file If file may not include a newline at the end, then: while IFS= read -r line || [ -n "$line" ]; do echo "$line" done <file

var='line 1 line 2 line3' readarray -t arr <<< "$var" or with a loop: arr=() while IFS= read -r line; do arr+=("$line") done <<< "$var"

var='line 1 line 2 line3' while IFS= read -r line; do echo "-$line-" done <<< "$var" or readarray -t arr <<< "$var" for i in "${arr[@]}";do echo "-$i-" done

while IFS= read -r line;do echo "**$line**" done < <(ping google.com) or with a pipe: ping google.com | while IFS= read -r line;do echo "**$line**" done

The NSString formatting supports all the format strings available on the printf ANSI-C function. The only addition made by the language is the %@ symbol used for formatting all the Objective-C objects. It is possible to format integers int myAge = 21; NSString *formattedAge = [NSString stringWith...

Let's assume that the field separator is : var='line: 1 line: 2 line3' while IFS= read -d : -r field || [ -n "$field" ]; do echo "-$field-" done <<< "$var" Output: -line- - 1 line- - 2 line3 -