python zlib ，zlib 壓縮流

zlib

字符串：使用zlib.compress能夠壓縮字符串。使用zlib.decompress能夠解壓字符串。

數據流：壓縮：compressobj，解壓：decompressobj

 

 

 

import zlib

import time

s='aldsfjdals拉薩的附近拉水電費拉克絲等級分sdfgfsdgsdfg ddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddddd類的撒酒瘋拉薩的解放路'.encode('utf-8')

#須要轉成bytes類型:

for i in range(0,15):

s+=s

print(len(s))

#---------------------------------------------------

str_time=time.time()

compress_str = zlib.compress(s)#進行壓縮

print(len(compress_str))

#print(zlib.decompress(compress_str).decode('utf-8'))#數據解壓

print(time.time()-str_time)

#-------------------------------------------------

str_obj=time.time()

level=9

c_obj = zlib.compressobj(level)#設置壓縮等級

com_obj_str = c_obj.compress(s)

print(len(com_obj_str))

print(time.time()-str_obj)

# 7995392

# 31149

# 0.12890625

# 16425

# 0.1015625

 注：compressobj返回一個壓縮對象，用來壓縮不能一會兒讀入內存的數據流。 level 從9到-1表示壓縮等級，其中1最快但壓縮度最小，9最慢但壓縮度最大，0不壓縮，默認是-1大約至關於與等級6，是一個壓縮速度和壓縮度適中的level。

 

 

 

壓縮內存中的二進制流

from io import BytesIO

import zlib

b_memory= BytesIO()

b_memory.write("不少數據sldkfjlsakjfsldakjflasjflaskdj".encode('utf-8'))

compress_str = zlib.compress(b_memory.getvalue())

print(compress_str)

print(zlib.decompress(compress_str).decode('utf-8'))

 

 

 

數據流壓縮和實際應用  

from io import BytesIOimport xlsxwriter as xwimport zlibbytesio = BytesIO()workbook = xw.Workbook(bytesio)work_sheet = workbook.add_worksheet('excel')merge_format=workbook.add_format(    {        "bold":True,        "bg_color":"red",        "valign":"top"    })for row in range(10):    for col in range(10):        work_sheet.write(row,col,"須要寫入的內容",merge_format)workbook.close()file_bytes = bytesio.getvalue()print("文件大小:{}".format(len(file_bytes)))with open('save.xlsx','wb') as f:    f.write(file_bytes)    f.flush()compress_file_bytes = zlib.compress(file_bytes,9)print("文件大小:{}".format(len(compress_file_bytes)))