记一次python3 大文件解压和操作

 先说下：所谓的大文件并不是压缩文件有多大，几十兆的文件而是解压后几百兆。其中就遇到解压不成功的情况.、读小文件时成功，大文件时失败等

def unzip_to_txt_plus(zipfilename):    zfile = zipfile.ZipFile(zipfilename, 'r')    for filename in zfile.namelist():        data = zfile.read(filename)        # data = data.decode('gbk').encode('utf-8')        data = data.decode('gbk', 'ignore').encode('utf-8')        file = open(filename, 'w+b')        file.write(data)        file.close()if __name__ == '__main__':    zipfilename = "E:\\share\\python_excel\\zip_to_database\\20171025.zip"    unzip_to_txt_plus(zipfilename)

注意参数：‘ignore’ ，因为默认是严格编码，如果不加这个参数就会报错。

因为该函数已经把文件编成utf-8 所以后面读取文件时成功，下面贴出读取大文件代码(忽略数据库相关)

# - coding: utf-8 -import csvimport linecacheimport xlrdimport MySQLdbdef txt_todatabase(filename, linenum):     # with open(filename, "r", encoding="gbk") as csvfile:     #      Read = csv.reader(csvfile)     #      count =0     #      for i in Read:     #      #     print(i)     #            count += 1     #            # print('hello')     #      print(count)     count = linecache.getline(filename, linenum)     print(count)     # with open("new20171028.csv", "w", newline="") as datacsv:     #      # dialect为打开csv文件的方式，默认是excel，delimiter="\t"参数指写入的时候的分隔符     #      csvwriter = csv.writer(datacsv, dialect=("excel"))     #      # csv文件插入一行数据，把下面列表中的每一项放入一个单元格（可以用循环插入多行）     #      csvwriter.writerow(["A", "B", "C", "D"])def bigtxt_read(filename):    with open(filename, 'r', encoding='utf-8') as data:        count =0        while 1:            count += 1            line = data.readline()            if 1000000 == count:                print(line)            if not line:                break        print(count)if __name__ == '__main__':    filename = '20171025.txt'    txt_todatabase(filename, 1000000)    bigtxt_read(filename)

经过对比，发现两个速度基本一样快。两百万行的数据是没压力的。