Champernowne up to me

Question

Inspired by this question.

Champernowne's constant is an infinite decimal number that consists of "0." followed by all natural numbers concatenated together. It begins like so: 0.123456781011121314151617181920212223242526272829303132333435363738394041424344454647484950, etc. The digits of Chamernowne's constant are sequence A033307 in the OEIS.

Your Task:

Write a program or function that, when given an integer as input, outputs/returns Champernowne's constant up to the first occurance of the input. For example, if the input is 13, you should output 0.12345678910111213. If you wish, for inputs greater than 0, you may drop the leading "0." in your output.

Input:

An integer, or a string containing only numbers.

Output:

Champernowne's constant up to the first occurance of the input.

Test Cases:

0   -> 0
1   -> 0.1 OR 1
14  -> 0.1234567891011121314 OR 1234567891011121314
91  -> 0.1234567891 OR 1234567891
12  -> 0.12 OR 12
101 -> 0.123456789101 OR 123456789101 

Scoring:

This is code-golf, lowest score in bytes wins!

Answer 1

05AB1E, 6 bytes

Code

LJ¹¡н«

Uses the 05AB1E encoding. Try it online!

Explanation

L         # Create the range [1, 2, ..., input]
 J        # Join into a single string
  ¹¡      # Split at occurences of the input
    н     # Take the first element
     «    # Append the input to the first element and implicitly output

Answer 2

Python 3, 70 63 61 bytes

A bunch of bytes removed thanks to @Rod, and some more thanks to @WheatWizard

lambda x:''.join(map(str,range(1,x))).split(str(x))[0]+str(x)

Try it online!

Answer 3

MATL, 20 15 14 bytes

U:VXzG&Yb1X)Gh

Takes the input as a string. Try it online!

Explanation

U      % Implicitly input a string. Convert to number
:      % Range from 1 to that
V      % Convert to string. Includes spaces as separators
Xz     % Remove spaces
G      % Push input again
&Yb    % Split at that. Gives a cell array
1X)    % Get contents of the first cell
G      % Push input again
h      % Concatenate horizontally. Implicitly display

Answer 4

Haskell, 82 73 55 bytes

x!b|or$zipWith(==)x b=x
x!(a:b)=a:x!b
(!(show=<<[1..]))

Try it online!

Explanation

First we define !. x!b truncates b to the first appearance of x. It does this by checking if b starts with x (or$zipWith(==)x b) returning x if it does and moving one down the string otherwise. Then we define our main function. Our main function is a point-free function that takes the constant (show=<<[1..]) and truncates it to the first appearance of x. This takes x as a string.

Answer 5

Pyth, 11 8 bytes

+hcjkSQ`

Try it online! or run a Test Suite.

Simply creates the constant (jkSQ) and then prints the constant up to the input (c ... `) followed by the input (+ ...).

Answer 6

Mathematica, 111 bytes

(m=Min@SequencePosition[s=Flatten[IntegerDigits/@Range[0,#]],t=IntegerDigits@#];FromDigits@Join[s[[;;m-1]],t])&