#!/usr/bin/env python
#_*_coding:utf-8_*_

import re, os, sys

def readFasta(file):
	if os.path.exists(file) == False:
		print('Error: "' + file + '" does not exist.')
		sys.exit(1)

	with open(file) as f:
		records = f.read()

	if re.search('>', records) == None:
		print('The input file seems not in fasta format.')
		sys.exit(1)

	records = records.split('>')[1:]
	myFasta = []
	for fasta in records:
		array = fasta.split('\n')
		name, sequence = array[0].split()[0], re.sub('[^ARNDCQEGHILKMFPSTWYV]', '', ''.join(array[1:]).upper())
		myFasta.append([name, sequence])
	return myFasta