读取文件，删除文本字段，保留数字字段

Question

我想写一些 python 脚本来绘制一些 .dat 文件。为此，我需要先处理文件。 .dat 文件如下所示：

(Real64
 (numDims 1)
 (size 513)
 (data 
   [ 90.0282291905089 90.94377050431068 92.31708247501335 93.38521400778211 94.60593575951782 95.67406729228657 97.04737926298925 97.96292057679104 ...]
 )
)

我想删除文本部分和 'normal' 括号。我只需要 [.......].

之间的数据

我试过这样的事情：

from Tkinter import Tk
from tkFileDialog import askopenfilename

# just a small GUI to get the file
Tk().withdraw()
filename = askopenfilename()

import numpy as np

with open(filename) as f:
    temp = f.readlines(5) #this is the line in the .dat file

    for i in range(len(temp)-1):
        if type(temp[i]) == str:
            del temp[i]

然而，这总是导致 'index of out bounds'。将不胜感激。

Answer 1

print re.findall("\[([0-9. ]+)\]",f.read())

这叫做 regular expression，上面说找到所有的东西，即两个方括号之间的数字句号和空格

 \[   # literal left bracket
 ( # capture the stuff in here
 [0-9. ] # accept 0-9 and . and space
+ # at least one ... probably more
 ) # end capture group
 \] # literal close bracket

或者你可以使用类似 pyparsing 的东西

inputdata = '''(Real64
 (numDims 1)
 (size 513)
 (data
   [ 90.0282291905089 90.94377050431068 92.31708247501335 93.38521400778211 94.60593575951782 95.67406729228657 97.04737926298925 97.96292057679104 ...]
 )
)
'''
from pyparsing import OneOrMore, nestedExpr

data = OneOrMore(nestedExpr()).parseString(inputdata)
print "GOT:", data[0][-1][2:-1]

Answer 2

I just need the data in between [.....]

# treat the whole thing as a string
temp = '''(Real64
 (numDims 1)
 (size 513)
 (data
   [ 90.0282291905089 90.94377050431068 92.31708247501335 ]
 )
)'''

# split() at open bracket; take everything right
# then split() at close bracket; take everything left
# strip() trailing / leading white space
number_string = temp.split('[')[1].split(']')[0].strip()

# convert to list of floats, because I expect you'll need to
number_list = [float(i) for i in number_string.split(' ')]

print number_string
print number_list

>>> 90.0282291905089 90.94377050431068 92.31708247501335
>>> [90.0282291905089, 90.94377050431068, 92.31708247501335]

读取文件，删除文本字段，保留数字字段

Read a file, drop text fields, keep numeric ones

python

regex

file

text-parsing

fileparsing