Given a string, you have to return a string in which each character (case-sensitive) is repeated once.

```python
double_char("String") ==> "SSttrriinngg"

double_char("Hello World") ==> "HHeelllloo  WWoorrlldd"

double_char("1234!_ ") ==> "11223344!!__  "
```
Good Luck!

Difficulty: EASY
Tags: String algorithms

Fundamentals

Starter code:
def double_char(s):
	

Solutions:
def double_char(s):
	return ''.join((c * 2 for c in s))


def double_char(s):
	res = ''
	for i in s:
		res += i * 2
	return res


def double_char(str):
	return ''.join((ch + ch for ch in str))


def double_char(str):
	return ''.join((c * 2 for c in str))


def double_char(s):
	return ''.join((char * 2 for char in s))


def double_char(s):
	y = list(s)
	length = len(y)
	ffs = list(range(0, length))
	blank = ''
	for i in ffs:
		blank = blank + y[i] + y[i]
	return blank


double_char = lambda s: ''.join((a * 2 for a in s))


double_char = lambda s: ''.join((c + c for c in s))


def double_char(s):
	result = ''
	for i in s:
		result += i + i
	return result


def double_char(s):
	return ''.join([x * 2 for x in s])


def double_char(s):
	return ''.join((a * 2 for a in s))


OUTPUT = '{0}{0}'.format

def double_char(s):
	return ''.join((OUTPUT(a) for a in s))


def double_char(s):
	result = ''
	for char in s:
		result += char * 2
	return result


def double_char(s):
	slowo = ''
	for char in s:
		char = 2 * char
		slowo += char
	return slowo


def double_char(s):
	answer = []
	for i in s:
		answer.append(i)
		answer.append(i)
	return ''.join(answer)


def double_char(s: str) -> str:
	return ''.join(list(map(lambda _: _ * 2, '|'.join(s).split('|'))))


def double_char(s):
	new = str()
	for i in s:
		new += i + i
	pass
	return new


def double_char(some_text):
	return ''.join([2 * letter for letter in some_text])


def double_char(s):
	return ''.join([2 * i for i in s])


def double_char(s):
	new_s = ''
	for c in s:
		new_s = '%s%c%c' % (new_s, c, c)
	return new_s


def double_char(s):
	s = list(s)
	lists = []
	for i in range(len(s)):
		lists.append(s[i] * 2)
	string = ''
	for i in range(len(lists)):
		string = string + lists[i]
	return string


def addition(char):
	return 2 * char

def double_char(s):
	result = list(map(addition, s))
	return ''.join(result)


def double_char(s):
	return ''.join(map(lambda x: ''.join(x), zip(s, s)))


def double_char(s):
	return ''.join([s[i] * 2 for i in range(len(s))])


def double_char(s):
	return reduce(lambda x, y: x + y, map(lambda x: 2 * x, s))


double_char = lambda s: ''.join([i * 2 for i in s])


def double_char(s):
	new_list = []
	for x in s:
		new_list.append(x)
		new_list.append(x)
	return ''.join(new_list)


def double_char(s):
	new = ''
	for char in s:
		new += char * 2
	return new


def double_char(s):
	return ''.join([character + character for character in s])


def double_char(s):
	z = ''
	for i in range(len(s)):
		z += s[i]
		z += s[i]
	return z


def double_char(s):
	total = ''
	for i in s:
		total += i
		total += i
	return total


def double_char(s):
	rtrn = ''
	for x in s:
		rtrn += x * 2
	return rtrn


def double_char(s):
	res = ''
	for t in range(len(s)):
		res += 2 * s[t]
	return res


def double_char(s):
	res = ''
	for l in s:
		res += l + l
	return res


def double_char(s):
	new_string = ''
	for char in s:
		char = char * 2
		new_string += char
	return new_string


def double_char(s):
	result = ''
	for sym in s:
		result += 2 * sym
	return result


def double_char(s):
	storage = ''
	for i in s:
		storage += i * 2
	return storage


def double_char(string):
	fin = ''
	for char in string:
		fin += char * 2
	return fin


def double_char(s):
	output = ''
	for character in s:
		output += 2 * character
	return output


def double_char(s):
	array = list(s)
	count = len(array) - 1
	while count >= 0:
		array.insert(count, array[count])
		count += -1
	return ''.join(array)


def double_char(s):
	lst = list(s)
	res = ''
	for el in lst:
		res += el * 2
	return res


def double_char(s):
	n = len(s)
	result = ''
	for i in range(n):
		result += s[i] * 2
	return result


def double_char(s):
	r = ''
	for x in s:
		r += 2 * x
	return r


def double_char(s):
	new_string = []
	for i in list(s):
		new_string.append(i + i)
	return ''.join(new_string)


def double_char(s):
	sss = ''
	for i in s:
		sss += i + i
	return sss


def double_char(s):
	Liste = []
	for i in s:
		Liste.append(i * 2)
	return ''.join(Liste)


def double_char(s):
	return_string = ''
	for i in s:
		return_string += i * 2
	return return_string


def double_char(s):
	my_list = ''
	for i in range(len(list(s))):
		my_list += str(list(s)[i] * 2)
	return my_list


def double_char(s):
	hold = ''
	for x in range(len(s)):
		hold += s[x] * 2
	return hold


def double_char(s):
	str = ''
	for i in s:
		str += 2 * i
	return str


def double_char(s):
	dbl = ''
	for i in range(len(s)):
		dbl = dbl + s[i] + s[i]
	return dbl


def double_char(s):
	l = list(s)
	res = []
	for letter in l:
		res.append(letter)
		res.append(letter)
	return ''.join(res)


def double_char(s):
	chars = []
	for char in s:
		chars.append(char)
	for i in range(len(chars)):
		chars[i] = chars[i] * 2
	return ''.join(chars)


def double_char(s):
	return ''.join([next_str + next_str for next_str in s])


def double_char(s):
	ans = []
	for i in s:
		a = i * 2
		ans.append(a)
	return ''.join(ans)


def double_char(s):
	s2 = ''
	for i in range(len(s)):
		s2 += 2 * s[i]
	return s2


def double_char(s):
	return ''.join(['{}'.format(i[0] + i[1]) for i in zip(s, s)])


def double_char(s):
	return ''.join([2 * letter for letter in s])


def double_char(s):
	return ''.join([''.join([r, r]) for r in s])


def double_char(s):
	lst = []
	for x in s:
		lst.append(x)
		lst.append(x)
	lst = ''.join(lst)
	return lst


def double_char(s):
	ans = ''
	for i in s:
		ans = ans + i * 2
	return ans


def double_char(s):
	derp = ''
	for letters in s:
		derp += letters + letters
	return derp


def double_char(s):
	return ''.join([s[x] * 2 for x in range(len(s))])


def double_char(s):
	word = ''
	for char in s:
		char = char * 2
		word += char
	return word


def double_char(s):
	res = ''
	for i in s:
		res += f'{i}{i}'
	return res


def double_char(s):
	l = list(s)
	r = []
	for i in range(len(l)):
		r.append(l[i] + l[i])
	return ''.join(r)


def double_char(s):
	t = ''
	for x in s:
		t += x + x
	return t


def double_char(s):
	double = ''
	for i in range(len(s)):
		double += '{}'.format(s[i] * 2)
	return double
double_char('String')


def double_char(s):
	x = []
	for i in range(len(s)):
		x.append(2 * s[i])
	return ''.join(x)


def double_char(s):
	double_s = ''
	for (i, x) in enumerate(s):
		double_s += x * 2
	return double_s


def double_char(s):
	k = list(s)
	arr = []
	for i in range(len(s)):
		arr.append(s[i])
		arr.append(s[i])
	return ''.join(arr)


def double_char(s):
	s = [lett * 2 for lett in s]
	y = ''
	x = 0
	while x < len(s):
		y += s[x]
		x += 1
	return y


def double_char(s):
	s = list(s)
	returnArr = []
	for i in range(len(s)):
		returnArr.append(s[i])
		returnArr.append(s[i])
	return ''.join(returnArr)


def double_char(s):
	x = ''
	for i in range(len(s)):
		x = x + s[i] + s[i]
	return x
	pass


def double_char(s):
	lisp = ''
	for char in s:
		lisp = lisp + char + char
	return lisp


def double_char(s):
	duplicados = ''
	for char in s:
		duplicados = duplicados + char + char
	return duplicados


def double_char(s):
	final_str = ''
	for i in s:
		final_str += i * 2
	return final_str


def double_char(s):
	returnString = ''
	i = 0
	while i < len(s):
		returnString = returnString + s[i] + s[i]
		i += 1
	return returnString


def double_char(s):
	return ''.join([2 * word for word in list(s)])


def double_char(s):
	new_string = ''
	for c in s:
		new_string = new_string + c + c
	return new_string


def double_char(s):
	return ''.join((''.join(i) for i in zip(s, s)))


def double_char(s):
	final_str = ''
	for char in s:
		final_str += char + char
	return final_str


def double_char(s):
	new_str = ''
	for i in s:
		new_str = new_str + i + i
	return new_str


def double_char(s):
	solution = ''
	for char in s:
		solution += char * 2
	return solution


def double_char(s):
	res = map(lambda x: x * 2, s)
	res = ''.join(res)
	return res


def double_char(s):
	return ''.join(map(lambda i: i + i, s))


from itertools import repeat

def double_char(s):
	return ''.join([x for item in s for x in repeat(item, 2)])


def double_char(s):
	a = ''
	for i in s:
		i = i * 2
		a += i
	return a