Using Range

Print the even numbers from 1 to 10

numbers = range(1, 11)
for number in numbers:
    if number % 2 == 0:
        print number

Simpler

for number in range(1, 11):
    if number % 2 == 0:
        print number

####Or for number in range(2, 11, 2): print number

Using Range to Loop Over Values in a List

In many languages we can use for value in values so we use the indexes to loop over values in a list

sequences = ['atg', 'gtc', 'atta']
for i in range(len(sequences)):
    print sequences[i]

And we can use this in Python to loop over two lists simultaneously

seqID = [27, 63, 42]
sequences = ['atg', 'gtc', 'atta']
for i in range(len(sequences)):
    print seqID[i], sequences[i]

Enumerate

Alternatively we can use enumerate

seqID = [27, 63, 42]
sequences = ['atg', 'gtc', 'atta']
for i, sequence in enumerate(sequences):
    print seqID[i], sequence