初级优化

import time
start = time.time()
import glob
import gzip
length=[]
with gzip.open('H-CK-1-3_clean.fq.gz','rt') as fp:
    i = 0 
    for line in fp:
        i += 1
        if i % 4 == 2: 
            if len(line)-1==50:
                length.append(i-1)
                length.append(i)
                length.append(i+1)
                length.append(i+2)
output_fastq = open("temp1.fq",'w')
def WRIRE1():
    N= 0       
    with gzip.open('H-CK-1-3_clean.fq.gz','rt') as fp:
        for line in fp:
            N += 1
            if N in length: 
                output_fastq.write(line)
WRIRE1()
output_fastq.close()    
end = time.time()
print("used %s s" % str(end - start))