在.txt文件中查找最新的修改表

Question

我是python編程新手。我正在處理一個文本文件，這是一個軟件的結果文件。基本上，每當我們使用該軟件時，它會將所有消息寫入結果文本文件（類似於日誌文件）。

現在我的問題是，該文件有很多表像下面這樣：

it may have some million lines above 
* ============================== INERTIA ============================== 
* File: /home/hamanda/transfer/cradle_vs30_dkaplus01_fwd_dl140606_fem140704_v00.bif 
* Solver: Nastran 
* Date: 24/09/14 
* Time: 10:29:50 
* Text: 
* 
* Area        +1.517220e+06 
* Volume        +5.852672e+06 
* 
* Structural mass     +4.594348e-02 
* MASS elements      +0.000000e+00 
* NSM on property entry    +0.000000e+00 
* NSM by parts (VMAGen and MPBalanc) +0.000000e+00 
* NSM by NSMCreate     +0.000000e+00 
* Total mass       +4.594348e-02 
* 
* Center of gravity 
* in the global   +1.538605e+02 +3.010898e+00 -2.524868e+02 
* coordinate system 
* 
* Moments of inertia +8.346990e+03 +6.187810e-01 +1.653922e+03 
* about the global  +6.187810e-01 +5.476398e+03 +4.176218e+01 
* coordinate system  +1.653922e+03 +4.176218e+01 +7.746156e+03 
* 
* Steiner share   +2.929294e+03 +4.016500e+03 +1.088039e+03 
* 
* Moments of inertia +5.417696e+03 +2.190247e+01 -1.308790e+02 
* about the center  +2.190247e+01 +1.459898e+03 +6.835397e+00 
* of gravity   -1.308790e+02 +6.835397e+00 +6.658117e+03 
* --------------------------------------------------------------------- 
some lines below and this table may repeat if user does any change to area and volume 
values.---------- 

現在我的問題是：如何打印在控制檯上的最新表。我能夠打印表格的第一次出現，現在我無法獲得表格的最新發生。

我需要在控制檯上打印最新的表格，我該怎麼做？ 這是我的代碼：

input = open(fileName,'r') 
    intable = False 
    for line in input: 
     if line.strip() == "* ============================== INERTIA ==============================": 
      intable = True 
     if line.strip() == "* ---------------------------------------------------------------------": 
      intable = False 
      break 
     if intable and line.strip().startswith("*"): 
      z1=(line.strip()) 
      print(z1) 

Answer 1

試試這個：

f = open(fileName,'r') 
content = f.readlines() 
content.reverse() 
for line in content: 
    if line.strip() == "* ============================== INERTIA ==============================": 
     index = content.index(line) 
     break 
for line in content[index::-1]: 
    print line 

Answer 2

您還可以捕獲列表中的文件數據，如下圖所示：

delimiter = '* ============================== INERTIA ==============================\n' 
    filedata = open(filepath).read().split(delimiter) 
    print filedata[-1] # This will print your latest occurrence of table 

我不知道有關代碼效率，但絕對有效。 在需要的情況下，您還可以列出表格的所有其他事件。

Answer 3

如果你可以使用bash，那麼下面是更有效的方法。

RESULT_FILE="result_text_file_name" 
START_LINE=$(grep -n "===== INERTIA ====" $RESULT_FILE | tail -1 | cut -d":" -f1) 
END_LINE=$(grep -n " --------------" $RESULT_FILE | tail -1 | cut -d":" -f1) 
LINE_COUNT=$(wc -l $RESULT_FILE | awk '{print $1}') 
tail -n `expr $LINE_COUNT - $FIRST_LINE + 1` $RESULT_FILE | head -n `expr $END_LINE - $FIRST_LINE + 1` 

還是你想蟒蛇，然後讀取後How to read lines from a file in python starting from the end

，並通過我指的上述頁寫的代碼！ （讀線相反的方式）

我認爲結果文件「的test.txt」

#!/usr/bin/env python 
import sys 
import os 
import string 

"""read a file returning the lines in reverse order for each call of readline() 
This actually just reads blocks (4096 bytes by default) of data from the end of 
the file and returns last line in an internal buffer. I believe all the corner 
cases are handled, but never can be sure...""" 

class BackwardsReader: 
    def readline(self): 
    while len(self.data) == 1 and ((self.blkcount * self.blksize) < self.size): 
     self.blkcount = self.blkcount + 1 
     line = self.data[0] 
     try: 
     self.f.seek(-self.blksize * self.blkcount, 2) # read from end of file 
     self.data = string.split(self.f.read(self.blksize) + line, '\n') 
     except IOError: # can't seek before the beginning of the file 
     self.f.seek(0) 
     self.data = string.split(self.f.read(self.size - (self.blksize * (self.blkcount-1))) + line, '\n') 

    if len(self.data) == 0: 
     return "" 

    # self.data.pop() 
    # make it compatible with python <= 1.5.1 
    line = self.data[-1] 
    self.data = self.data[:-1] 
    return line + '\n' 

    def __init__(self, file, blksize=4096): 
    """initialize the internal structures""" 
    # get the file size 
    self.size = os.stat(file)[6] 
    # how big of a block to read from the file... 
    self.blksize = blksize 
    # how many blocks we've read 
    self.blkcount = 1 
    self.f = open(file, 'rb') 
    # if the file is smaller than the blocksize, read a block, 
    # otherwise, read the whole thing... 
    if self.size > self.blksize: 
     self.f.seek(-self.blksize * self.blkcount, 2) # read from end of file 
    self.data = string.split(self.f.read(self.blksize), '\n') 
    # strip the last item if it's empty... a byproduct of the last line having 
    # a newline at the end of it 
    if not self.data[-1]: 
     # self.data.pop() 
     self.data = self.data[:-1] 


if(__name__ == "__main__"): 
    f = BackwardsReader("test.txt") 
    end_line = "---------------------------------------------------" 
    start_line = "========= INERTIA =======" 
    lines = [] 

    intable = False 
    line = f.readline() 
    while line: 
    if line.find(end_line) >= 0: 
     intable = True 
    if intable: 
     lines.append(line) 
     if line.find(start_line) >= 0: 
     break 
    line = f.readline() 

    lines.reverse() 

    print "".join(lines) 

和測試的結果！

[my server....]$ wc -l test.txt 
 
34008720 test.txt 
 

 
[my server....]$ time python test.py 
 
* ============================== INERTIA ============================== 
 
* File: /home/hamanda/transfer/cradle_vs30_dkaplus01_fwd_dl140606_fem140704_v00.bif 
 
* Solver: Nastran 
 
* Date: 24/09/14 
 
* Time: 10:29:50 
 
* Text: 
 
* 
 
* Area        +1.517220e+06 
 
* Volume        +5.852672e+06 
 
* 
 
* Structural mass     +4.594348e-02 
 
* MASS elements      +0.000000e+00 
 
* NSM on property entry    +0.000000e+00 
 
* NSM by parts (VMAGen and MPBalanc) +0.000000e+00 
 
* NSM by NSMCreate     +0.000000e+00 
 
* Total mass       +4.594348e-02 
 
* 
 
* Center of gravity 
 
* in the global   +1.538605e+02 +3.010898e+00 -2.524868e+02 
 
* coordinate system 
 
* 
 
* Moments of inertia +8.346990e+03 +6.187810e-01 +1.653922e+03 
 
* about the global  +6.187810e-01 +5.476398e+03 +4.176218e+01 
 
* coordinate system  +1.653922e+03 +4.176218e+01 +7.746156e+03 
 
* 
 
* Steiner share   +2.929294e+03 +4.016500e+03 +1.088039e+03 
 
* 
 
* Moments of inertia +5.417696e+03 +2.190247e+01 -1.308790e+02 
 
* about the center  +2.190247e+01 +1.459898e+03 +6.835397e+00 
 
* of gravity   -1.308790e+02 +6.835397e+00 +6.658117e+03 
 
* --------------------------------------------------------------------- 
 

 

 
real \t 0m0.025s 
 
user \t 0m0.018s 
 
sys \t 0m0.006