python - 过滤和解析 Solar Region Summary 文件中的文本

Question

我试图过滤一些 .txt 文件，这些文件以 YYYYMMDD 格式的日期命名，并且包含一些关于太阳事件区域的数据。我编写了一个代码，给定一个 YYYYMMDD 格式的日期，它可以列出一个时间范围内的文件，我希望我正在寻找的事件区域是这样的，并根据该条目解析信息。这些 txt 的示例可以在下面看到，有关它的更多信息(如果您感到好奇)可以在 SWPC website 上看到。 .

:Product: 0509SRS.txt
:Issued: 2012 May 09 0030 UTC
# Prepared jointly by the U.S. Dept. of Commerce, NOAA,
# Space Weather Prediction Center and the U.S. Air Force.
#
Joint USAF/NOAA Solar Region Summary
SRS Number 130 Issued at 0030Z on 09 May 2012
Report compiled from data received at SWO on 08 May
I.  Regions with Sunspots.  Locations Valid at 08/2400Z 
Nmbr Location  Lo  Area  Z   LL   NN Mag Type
1470 S19W68   284  0030 Cro  02   02 Beta
1471 S22W60   277  0120 Cso  05   03 Beta
1474 N14W13   229  0010 Axx  00   01 Alpha
1476 N11E35   181  0940 Fkc  17   33 Beta-Gamma-Delta
1477 S22E73   144  0060 Hsx  03   01 Alpha
IA. H-alpha Plages without Spots.  Locations Valid at 08/2400Z May
Nmbr  Location  Lo
1472  S28W80   297
1475  N05W05   222
II. Regions Due to Return 09 May to 11 May
Nmbr Lat    Lo
1460 N16    126
1459 S16    110

我用来解析这些 txt 文件的代码是:

import glob

def seeker(noaa_number, t_start, path = None):
    '''
    This function will open an SRS file
    and look for each line if the given AR
    (specified by its NOAA number) is there.
    If so, this function should grab the
    entries and return them.
    '''

    #defaulting path if none is given
    if path is None:
        #assigning
        path = 'defaultpath'


    #listing the items within the directory
    files = sorted(glob.glob(path+'*.txt'))

    #finding the index in the list of
    #the starting time
    index = files.index(path+str(t_start)+'SRS.txt')

    #looping over each file
    for file in files[index: index+20]:

        #opening file
        f = open(file, 'r')

        #reading the lines
        text = f.readlines()

        #looping over each line in the text
        for line in text:

            #checking if the noaa number is mentioned
            #in the given line
            if noaa_number in line:

                #test print
                print('Original line: ', line)

                #slicing the text to get the column values
                nbr = line[:4]
                Location = line[5:11]
                Lo = line[14:18]
                Area = line[19:23]
                Z = line[24:28]
                LL = line[29:31]
                NN = line[34:36]
                MagType = line[37:]

                #test prints
                print('nbr: ', nbr)
                print('location: ', Location)
                print('Lo: ', Lo)
                print('Area: ', Area)
                print('Z: ', Z)
                print('LL: ', LL)
                print('NN: ', NN)
                print('MagType: ', MagType)

     return

我对此进行了测试，它可以正常工作，但我有点笨，原因有二:

• 尽管这些文件是按照标准制作的，但考虑到我按索引对数组进行切片的方式，只需要一个额外的空间就会使代码崩溃。有更好的选择吗？

• 表 IA 和 II 上的信息与我无关，因此理想情况下，我想阻止我的代码扫描它们。由于第一列的行数不同，是否可以告诉代码何时停止阅读给定文档？

感谢您的宝贵时间!

Answer 1

健壮性:

您可以使用 .split() 方法将行拆分为列表，而不是按绝对位置进行切片。这将对额外的空间具有鲁棒性。

所以代替

Location = line[5:11]
Lo = line[14:18]
Area = line[19:23]
Z = line[24:28]
LL = line[29:31]
NN = line[34:36]

你可以使用

Location = line.split()[1]
Lo = line.split()[2]
Area = line.split()[3]
Z = line.split()[4]
LL = line.split()[5]
NN = line.split()[6]

如果你想让它更快，你可以拆分列表一次，然后只从同一个列表中提取相关数据，而不是每次都拆分它:

data = line.split()
Location = data[1]
Lo = data[2]
Area = data[3]
Z = data[4]
LL = data[5]
NN = data[6]

停止:

要阻止它在传递相关数据后继续读取文件，您可以在它不再在行中找到 noaa_number 时退出循环

# In the file function but before looping through the lines. 

started_reading = False ## Set this to false so 
                        ## that it doesn't exit
                        ## before it gets to the 
                        ## relevant data

for line in text:
    if noaa_number in line:
        started_reading = True 

        ## Parsing stuff

    elif started_reading is True:
        break # exits the loop