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D Scripting Toolbox Cheat Sheet by

Collection of library methods useful for scripting.

Read File

void main() {
   import std.file;
   auto data = readText("filename.ext");
readText reads the entire file into memory.

Matching Beginning or End

import std.algorithm;
auto data = "word word"
assert(data == " word");
skipOver will not only identify if the string is found at the beginning, but also move data past the string.

Removing Whitespace

import std.string;
auto data = " str ";
assert(data.strip == "str");
assert(data.stripLeft == " str");
assert(data.stripRight == "str ");
strip Along with whitespace an argument can be past in to specify a specific string to strip off.

Find a String

import std.algorithm;

auto haystack = "some long name";
auto needle = "long";

find is a general function that works on any range. So it can be used with numbers and other contai­ners. Similar to count and filter it is possible to specify more complex condit­ions.

Split Strings

import std.algorithm;

auto data = "one str\ntwo";
assert(data.splitter(" ").equal(
    ["one", "str\ntwo"]));

import std.array;

assert(data.split().equal(["one", "str", "two"]));
splitter is a lazy operation with no memory alloca­tion, split eagerly evaluates into a new dynamic array. The second, when passing no arguments will also split on all whitespace including new lines.

Head and Tail

import std.range;

auto data = ["one", "two"];
auto head = data.front;
auto tail = data.dropOne;
dropOne modifies and returns the same range having removed the first element.


auto content = ["post" , "tweet", "video", "talk"];
auto begin = content[0..2];
auto end = content[2..$];
// content is ["post" , "tweet", "video", "talk"];
// begin is ['post', 'tweet']
// end is ['video', 'talk']
The right index is exclusive and does not include that indexes content. These made no modifi­cations to the original array and no allocation was performed. This does mean modifying the slice will modify the original.

Remove the Middle of Array

import std.algorithm;
import std.typecons : tuple;
auto content = ["post" , "tweet", "video", "talk"];
content = content.remove(tuple(1,3));
assert(content.equal(["post" , "talk"]) );
remove() resembles removing elements at a specified index. A tuple can be utilized to provide a sequence of indexes to be removed, and like slicing the first number is inclusive and last number is exclusive.

Execute a Program

import std.process;
import std.exception;

auto res = execute(["app name", "arg 1", "arg 2"]);
enforce(res.status == 0, "App exited with failure");

import std.stdio;
execute will run the applic­ation to completion and store the output for review.

Handling Paths

import std.path;
auto a = "foo";
auto b = "bar";

assert([a, b].joiner("/").equal(a.buildPath(b)));

assert("file.ext".extension == ".ext");
assert("file.ext".setExtension("gif") == "file.gif");
assert("file.ext".stripExtension == "file");
There are lots of utilities in std.path


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