Python 是否从文件头获取特定元素？

因此，我有以下格式的数据：

#NUMBER OF AGES=37 MAGS= 5
#----------------------------------------------------       
#MIX-LEN  Y      Z          Zeff        [Fe/H] [a/Fe]
# 1.9380  0.3300 3.1125E-04 1.5843E-04  -1.99   0.40
#----------------------------------------------------       
#**PHOTOMETRIC SYSTEM**: SDSS (AB)
#----------------------------------------------------       
#AGE= 1.000 EEPS=276
#EEP   M/Mo    LogTeff  LogG   LogL/Lo sdss_u  sdss_g  sdss_r  sdss_i  sdss_z  
   3  0.105051  3.5416  5.3073 -2.7281 17.2434 13.9245 12.2511 11.5059 11.0920
   4  0.118159  3.5519  5.2644 -2.5931 16.5471 13.4392 11.8286 11.1502 10.7665
   5  0.133632  3.5623  5.2211 -2.4547 15.8825 12.9522 11.4091 10.7861 10.4301
   6  0.156724  3.5737  5.1745 -2.2933 15.1633 12.4008 10.9372 10.3638 10.0348
   7  0.194206  3.5861  5.1259 -2.1020 14.3673 11.7681 10.3975  9.8690  9.5654

#AGE= 1.250 EEPS=275
#EEP   M/Mo    LogTeff  LogG   LogL/Lo sdss_u  sdss_g  sdss_r  sdss_i  sdss_z  
   4  0.105349  3.5419  5.3062 -2.7248 17.2255 13.9125 12.2406 11.4972 11.0840
   5  0.118453  3.5521  5.2635 -2.5901 16.5322 13.4285 11.8194 11.1424 10.7593
   6  0.133982  3.5625  5.2202 -2.4518 15.8684 12.9418 11.4002 10.7783 10.4228
   7  0.157170  3.5739  5.1736 -2.2903 15.1503 12.3907 10.9286 10.3560 10.0274
   8  0.193935  3.5860  5.1253 -2.1021 14.3683 11.7688 10.3980  9.8694  9.5657
   9  0.233067  3.5953  5.0847 -1.9445 13.7342 11.2608  9.9652  9.4664  9.1794
  10  0.253422  3.5994  5.0635 -1.8706 13.4408 11.0263  9.7653  9.2787  8.9986
  11  0.263033  3.6012  5.0556 -1.8395 13.3177 10.9277  9.6812  9.1997  8.9225
  12  0.269548  3.6022  5.0484 -1.8175 13.2345 10.8597  9.6223  9.1439  8.8684

#AGE= 1.500 EEPS=274
#EEP   M/Mo    LogTeff  LogG   LogL/Lo sdss_u  sdss_g  sdss_r  sdss_i  sdss_z  
   5  0.107932  3.5440  5.2974 -2.6971 17.0780 13.8121 12.1528 11.4242 11.0175
   6  0.121259  3.5542  5.2549 -2.5632 16.3994 13.3328 11.7366 11.0714 10.6940
   7  0.137720  3.5647  5.2112 -2.4220 15.7312 12.8387 11.3119 10.7002 10.3502
   8  0.163277  3.5763  5.1639 -2.2544 14.9976 12.2706 10.8261 10.2628  9.9394
   9  0.199555  3.5876  5.1176 -2.0757 14.2622 11.6834 10.3250  9.8017  9.5010

我已经想出了如何用这个理论来阅读专栏：

sdss_g = []
sdss_r = []

with open ("/Users/Wilson/research/isochrones/SDSSugriz/fehm20afep4y33.SDSSugriz") as f:
   for _ in xrange(9):
        next(f)

   for line in f: 
        cols = line.split()
        g = (float(cols[6]))
        r = (float(cols[7]))
        print 'g'
        print g
        print 'r'
        print r
        sdss_g.append(g)
        sdss_r.append(r)

但这不起作用，它给了我一个错误：

Traceback (most recent call last):
  File "isochronereader.py", line 18, in <module>
    g = (float(cols[6]))
IndexError: list index out of range

我很确定这是因为我没有考虑行空间和字符串格式的新标题，但是列表索引超出范围似乎不是解决这个问题的正确指标

尽管如此，我不知道如何解释数据之间的标题和空格，我想弄清楚这一点。我还想读每个标题中的年龄。由于这个文本文件的格式，我不能使用genfromtxt，我也不知道该怎么做，特别是因为下一个新标题的行数不一致，所以我不能在特定的行数之后读取它

最后，我希望能够读懂sdss_g和sdss_r，并知道每个sdss_g和sdss_r元素与哪个年龄相关。有没有一个简单的方法可以让我这样做？

您可以这样做：

sdss_g = []
sdss_r = []

with open ("/Users/Wilson/research/isochrones/SDSSugriz/fehm20afep4y33.SDSSugriz") as f:
    for line in f:
        if not line.isspace() and not line.startswith("#"):
            print line
            cols = line.split()
            g = (float(cols[6]))
            r = (float(cols[7]))
            print 'g'
            print g
            print 'r'
            print r
            sdss_g.append(g)
            sdss_r.append(r)

您可以这样做：

sdss_g = []
sdss_r = []

with open ("/Users/Wilson/research/isochrones/SDSSugriz/fehm20afep4y33.SDSSugriz") as f:
    for line in f:
        if not line.isspace() and not line.startswith("#"):
            print line
            cols = line.split()
            g = (float(cols[6]))
            r = (float(cols[7]))
            print 'g'
            print g
            print 'r'
            print r
            sdss_g.append(g)
            sdss_r.append(r)

---

如果首先拆分数据，则可以使用CSV库：

import csv, re, StringIO

with open("/Users/Wilson/research/isochrones/SDSSugriz/fehm20afep4y33.SDSSugriz", "r") as f_input:
    data = f_input.read()
    lblocks = re.findall(r"#AGE=\s+?(.*?)\s+(?:.*?[\r\n]|\Z){2}(.*?(?=#AGE|\Z|^$))", data, re.S + re.M)

    for age, block in lblocks:
        csv_reader = csv.reader(StringIO.StringIO(block), delimiter=" ", skipinitialspace=True)
        print "Age:", age

        for cols in csv_reader:
            print "  sdss_g %s, sdss_r %s" % (cols[6], cols[7])

这将提供以下输出：

Age: 1.000
  sdss_g 13.9245, sdss_r 12.2511
  sdss_g 13.4392, sdss_r 11.8286
  sdss_g 12.9522, sdss_r 11.4091
  sdss_g 12.4008, sdss_r 10.9372
  sdss_g 11.7681, sdss_r 10.3975
Age: 1.250
  sdss_g 13.9125, sdss_r 12.2406
  sdss_g 13.4285, sdss_r 11.8194
  sdss_g 12.9418, sdss_r 11.4002
  sdss_g 12.3907, sdss_r 10.9286
  sdss_g 11.7688, sdss_r 10.3980
  sdss_g 11.2608, sdss_r 9.9652
  sdss_g 11.0263, sdss_r 9.7653
  sdss_g 10.9277, sdss_r 9.6812
  sdss_g 10.8597, sdss_r 9.6223
Age: 1.500
  sdss_g 13.8121, sdss_r 12.1528
  sdss_g 13.3328, sdss_r 11.7366
  sdss_g 12.8387, sdss_r 11.3119
  sdss_g 12.2706, sdss_r 10.8261
  sdss_g 11.6834, sdss_r 10.3250

---

使用Python 2.7进行测试，如果数据首先被拆分，则可以使用CSV库：

import csv, re, StringIO

with open("/Users/Wilson/research/isochrones/SDSSugriz/fehm20afep4y33.SDSSugriz", "r") as f_input:
    data = f_input.read()
    lblocks = re.findall(r"#AGE=\s+?(.*?)\s+(?:.*?[\r\n]|\Z){2}(.*?(?=#AGE|\Z|^$))", data, re.S + re.M)

    for age, block in lblocks:
        csv_reader = csv.reader(StringIO.StringIO(block), delimiter=" ", skipinitialspace=True)
        print "Age:", age

        for cols in csv_reader:
            print "  sdss_g %s, sdss_r %s" % (cols[6], cols[7])

这将提供以下输出：

Age: 1.000
  sdss_g 13.9245, sdss_r 12.2511
  sdss_g 13.4392, sdss_r 11.8286
  sdss_g 12.9522, sdss_r 11.4091
  sdss_g 12.4008, sdss_r 10.9372
  sdss_g 11.7681, sdss_r 10.3975
Age: 1.250
  sdss_g 13.9125, sdss_r 12.2406
  sdss_g 13.4285, sdss_r 11.8194
  sdss_g 12.9418, sdss_r 11.4002
  sdss_g 12.3907, sdss_r 10.9286
  sdss_g 11.7688, sdss_r 10.3980
  sdss_g 11.2608, sdss_r 9.9652
  sdss_g 11.0263, sdss_r 9.7653
  sdss_g 10.9277, sdss_r 9.6812
  sdss_g 10.8597, sdss_r 9.6223
Age: 1.500
  sdss_g 13.8121, sdss_r 12.1528
  sdss_g 13.3328, sdss_r 11.7366
  sdss_g 12.8387, sdss_r 11.3119
  sdss_g 12.2706, sdss_r 10.8261
  sdss_g 11.6834, sdss_r 10.3250

---

使用Python 2.7

测试，在你跳过的前九个外的空白和注释行将仍然被处理，除非你添加，例如，如果不是行或LI. StastSuff:继续。你跳过的前九个外的空白和注释行将仍然被处理，除非你添加，例如如果不是行或LI. StastFiel:继续。