Row_Transposition_Cipher.py

text = "attack postponed untill two am".replace(' ','')

key = 4312567
sliced = [ int(k) for k in str(key) ]

#a special function to calculate how many cells at least it would take to store the key and text into a matrix.
least_cells = lambda x=1: x*len(sliced) if x*len(sliced) >= len(text)+len(sliced) else least_cells(x+1)

rows = least_cells() // len(sliced)
matrix = []
step = 0
for i, j in enumerate(sliced):
	step = 0
	col =[j]
	for r in range(rows-1):
		try:col.append(text[i+step])
		except:pass
		step += len(sliced)
	matrix.append(col)

matrix = sorted(matrix, key=lambda x:x[0])

for i in matrix:
	for j in i:
		if isinstance(j, str):
			print(j, end="")