python 中输出指定序列的反向互补序列

001、方法1

root@PC1:/home/test3# ls
test.py
root@PC1:/home/test3# cat test.py          ## 测试程序
#!/usr/bin/python
result = ""
str1 = "ACGTACGTACGTCACGTCAGCTAGAC"        ## 测试字符串
for i in reversed(str1):
    if i == "A":
        result += "T"
    elif i == "T":
        result += "A"
    elif i == "C":
        result += "G"
    elif i == "G":
        result += "C"

print(result)
root@PC1:/home/test3# python test.py       ## 程序运行结果
GTCTAGCTGACGTGACGTACGTACGT

002、方法2

root@PC1:/home/test3# ls
test.py
root@PC1:/home/test3# cat test.py                   ## 测试程序
#!/usr/bin/python

str1 = "ACGTACGTACGTCACGTCAGCTAGAC"
dict1 = {"A":"T", "T":"A", "C":"G", "G":"C"}
result = [dict1[k] for k in reversed(str1)]
print("".join(result))

root@PC1:/home/test3# python test.py                ## 运行程序
GTCTAGCTGACGTGACGTACGTACGT

参考：https://www.jianshu.com/p/2475c3240a67