double_char

Requirements:

• string building and filtering

• returning a value

Given a string, return a string where for every char in the original, there are two chars.

double_char("The") -> "TThhee"
double_char("AAbb") -> "AAAAbbbb"
double_char("Hi-There") -> "HHii--TThheerree"

This exercise was taken from codingbat.com and has been adapted for the Python language. There are many great programming exercises there, but the majority are created for Java.

Starter Code

def double_char(string: str) -> str:
    pass


result = double_char('The')
print(result)

Tests

from main import double_char


def test_double_char_1():
    assert double_char('The') == 'TThhee'


def test_double_char_2():
    assert double_char('AAbb') == 'AAAAbbbb'


def test_double_char_3():
    assert double_char('Hi-There') == 'HHii--TThheerree'


def test_double_char_4():
    assert double_char('Word!') == 'WWoorrdd!!'


def test_double_char_5():
    assert double_char('!!') == '!!!!'


def test_double_char_6():
    assert double_char('') == ''


def test_double_char_7():
    assert double_char('a') == 'aa'


def test_double_char_8():
    assert double_char('.') == '..'


def test_double_char_9():
    assert double_char('aa') == 'aaaa'