python 中 实现统计fastq碱基序列的长度

001、

root@PC1:/home/test# ls
a.fastq  test.py
root@PC1:/home/test# cat a.fastq                                 ## 测试fastq文件
@DJB775P1:248:D0MDGACXX:7:1202:12362:49613
TGCTTACTCTGCGTTGATACCACTGCTTAGATCGGAAGAGCACACGTCTGAA
+
JJJJJIIJJJJJJHIHHHGHFFFFFFCEEEEEDBD?DDDDDDBDDDABDDCA
@DJB775P1:248:D0MDGACXX:7:1202:12782:49716
CTCTGCGTTGATACCACTGCTTACTCTGCGTTGATACCACTGCTTAGATCGG
+
IIIIIIIIIIIIIIIHHHHHHFFFFFFEECCCCBCECCCCCCCCCCCCCCCC
root@PC1:/home/test# cat test.py                                 ## 测试程序
#!/usr/bin/python

in_file = open("a.fastq", "r")

dict1 = {}
idx = 0

for i in in_file:
    idx += 1
    i = i.strip()
    if idx % 4 == 1:
        key = i
        dict1[key] = ""
    elif idx % 4 == 2:
        dict1[key] = len(i)

for i in dict1:
    print(i + "-------" + str(dict1[i]))

in_file.close()
root@PC1:/home/test# python test.py                              ## 执行程序
@DJB775P1:248:D0MDGACXX:7:1202:12362:49613-------52
@DJB775P1:248:D0MDGACXX:7:1202:12782:49716-------52

参考：https://www.jianshu.com/p/5ee54bea4cb0