最长和最短序列，Python

Question

我有这个程序来生成随机N序列

import random
N = 5
def randseq(abc, length):
    return "".join([random.choice(abc) for i in range(random.randint(1, length))])
for i in range(N):
    print(f'Sequence {i+1}:')
    print(randseq("ATCG", 120))

我拿到序列了

顺序1：

TGGTACAGCGTGCTTAATGTTAACCTGTCTGGCAGGTAACTATTCTCCT

顺序2：

cGTATATGCTTCCTCTTCAGCGACCTTGCGATTGCGATTAGTGTCGGCCATGTGTCCCTGGAGTGGTCCTTAGATGACCATATACGTTTTTAGAGCTATGTGGG

顺序3：

CACAGCTCCAATG . . .

序列N：

如何打印最长和最短的N序列及其长度

Answer 1

请检查我的密码。描述就在里面

import random


def randseq(abc, length):
    return "".join([random.choice(abc) for i in range(random.randint(1, length))])


# You should move the input value to the main part of code
# If not, it will treat as global variable
N = 5

# Init the longest seq with shortest one (empty string) 
# to make sure that all random seq must longer than this init
longest_seq = ""

# Init the shortest seq with longest one 
# (assume that randseq("ATCG", 1000) is long enough) 
# to make sure that all random seq must shorter than this init
shortest_seq = randseq("ATCG", 1000)

for i in range(N):
    print(f'Sequence {i+1}:')
    seq = randseq("ATCG", 120)
    
    # Find the longest one then update it to the longest_seq variable
    if len(seq) > len(longest_seq):
        longest_seq = seq
    
    # Find the shortest one then update it to the shortest_seq variable
    if len(seq) < len(shortest_seq):
        shortest_seq = seq
    
    print(seq)
   
print("") 
print('The longest seq is ', longest_seq)
print('The lenght of longest seq is ', len(longest_seq))
print('The shortest is ', shortest_seq)
print('The lenght of shortest seq is ', len(shortest_seq))

示例结果（它是随机的，因此在运行时与您的结果不同）

Sequence 1:
CGGTGATCGCGATTACTGCCCGGCCTTGTCCACTCACAGCGATAACAGTGCTTATAGATCTCTCAAGTCTACCGTCTCACCCGTTGATTACCAA
Sequence 2:
AAGGTCAAGATTCGAATTCGTATCGCCGTATGGATAGGCGAAACGAGGGGTGGCTAAGGGGTAGACAGCAGAGCCGCTTTTGTACACCGTAAAACGGACGGTTCAGAACCGGAGGTACG
Sequence 3:
ACGGCCTCATGGATAATGCCCGGGGGAACAGGGAAGGAAAGATTTTGTCAAACTGATTCAGTTAC
Sequence 4:
GATACA
Sequence 5:
ATCGAAAGGAATATCTGTACGGGACGTTTGGTCTCGAGCCTAGCGTAAGCCGCCCGCAATTCGCTCTGATGAGCTACCG

The longest seq is  AAGGTCAAGATTCGAATTCGTATCGCCGTATGGATAGGCGAAACGAGGGGTGGCTAAGGGGTAGACAGCAGAGCCGCTTTTGTACACCGTAAAACGGACGGTTCAGAACCGGAGGTACG
The lenght of longest seq is  119
The shortest is  GATACA
The lenght of shortest seq is  6

预防措施：

在某些（很少）情况下，最短序列的初始化可能太小（在所有随机序列中最小）。如果发生这种情况，程序将失败。您可以增加randseq输入的长度，以减少遇到此问题的可能性

比如说

您可以从以下位置进行更改：

shortest_seq = randseq("ATCG", 1000)

致：

shortest_seq = randseq("ATCG", 10000)