# define a new sequence
seq = 'ACGT'
# define a new sequence
seq = "ACGT"
# Get a character from a string
seq[1]
'C'
# get the length of a sequence
len(seq)
4
# empty string (epsilon)
e = ''
len(e)
0
# concatenation
seq1 = 'AACC'
seq2 = 'GGTT'
print(seq1 + seq2)
AACCGGTT
seqs = ['A', 'C', 'G', 'T']
print(''.join(seqs))
ACGT
# generate a random nucleotide
import random
random.choice('ACGT')
'T'
# generate a random sequence
seq = ''
for _ in range(10):
seq += random.choice('ACGT')
print(seq)
TCAATTCCAT
# another way to generate a random sequence
seq = ''.join([random.choice('ACGT') for _ in range(10)])
print(seq)
GATCACCGAC
# get a substring
seq[1:3]
'AT'
# get a prefix
seq[:3]
'GAT'
# get a suffix
seq[7:]
'GAC'
# another way to get a suffix
seq[-3:]
'GAC'