Question

我有一个包含这样数据的文件：

# 0 867.691994 855.172889 279.230411 -78.951239 55.994189 -164.824148
# 0 872.477810 854.828159 279.690170 -78.950558 55.994391 -164.823700
...
893.270609 1092.179289 184.692319
907.682255 1048.809187 112.538457
...
# 0 877.347791 854.481104 280.214892 -78.949869 55.994596 -164.823240
...
893.243290 1091.395104 184.726720
907.682255 1048.809187 112.538457
...
# 0 882.216053 854.135168 280.745489 -78.948443 55.996206 -164.821887

我想通过以下方式只读取注释行之间的行：我将两个相邻注释之间的所有行读入某个数组（不保存到文件中），并使用它，然后读取下一个块进入数组，等等。

我设法让它读一个街区：

def main():
    sourceFile = 'test.asc'
    print 'Extracting points ...'
    extF = open(sourceFile, 'r')
    block, cursPos = readBlock(extF)
    extF.close()
    print 'Finished extraction'

def readBlock(extF):
    countPnts = 0
    extBlock = []
    line = extF.readline()
    while not line.startswith('#'):
        extPnt = Point(*[float(j) for j in line.split()])
        countPnts += 1
        extBlock.append(extPnt)
        line = extF.readline()

    cursPos = extF.tell()
    print 'Points:', countPnts
    print 'Cursor position:', cursPos
    return extBlock, cursPos

它完美地工作，但仅适用于一个数据块。我不能让它在从一个块到另一个块的注释行之间进行迭代。我正在考虑光标位置，但无法实现。请给我一些关于此的提示。谢谢。

更新我实现了MattH的想法如下：

def blocks(seq):
    buff = []
    for line in seq:
        if line.startswith('#'):
            if buff:
                #yield "".join(buff)
                buff = []
        else:
            # I need to make those numbers float
            line_spl = line.split()
            pnt = [float(line_spl[k]) for k in range(len(line_spl))]
            #print pnt
            buff.append(Point(*pnt))
    if buff:
        yield "".join(buff)

然后，如果我运行它：

for block in blocks(extF.readlines()):
    print 'p'

我只是空窗口，虽然print 'p'循环中有for。所以，有几个问题：

是什么？

if buff:
    yield "".join(buff)

做什么？当我评论它没有任何变化......

为什么for - 循环内的命令不起作用？

这个函数是生成器，所以我无法访问之前处理过的行，是吗？

解决方案

我设法使用MattH和Ashwini Chaudhari的想法自己做。最后，我得到了这个：

def readBlock(extF):
    countPnts = 0
    extBlock = []
    line = extF.readline()
    if line.startswith('#'):
        line = extF.readline()
    else:
        while not line.startswith('#'):
            extPnt = Point(*[float(j) for j in line.split()])
            countPnts += 1
            extBlock.append(extPnt)
            line = extF.readline()

    return extBlock, countPnts

运行它：

while extF.readline():
    block, pntNum = readBlock(extF)

它完全符合我的需要。

谢谢大家。

Answer 1

这是两个简单的生成器，一个生成所有非注释块，另一个生成注释之间的非注释块。更新了两种不同的可能性，并进行了更新，以便在同一功能中进行分割和连接以保持一致性。

sample = """Don't yield this
# 0 867.691994 855.172889 279.230411 -78.951239 55.994189 -164.824148
# 0 872.477810 854.828159 279.690170 -78.950558 55.994391 -164.823700
...
893.270609 1092.179289 184.692319
907.682255 1048.809187 112.538457
...
# 0 877.347791 854.481104 280.214892 -78.949869 55.994596 -164.823240
...
893.243290 1091.395104 184.726720
907.682255 1048.809187 112.538457
...
# 0 882.216053 854.135168 280.745489 -78.948443 55.996206 -164.821887
Don't yield this either"""

def blocks1(text):
  """All non-comment blocks"""
  buff = []
  for line in text.split('\n'):
    if line.startswith('#'):
      if buff:
        yield "\n".join(buff)
        buff = []
    else:
      buff.append(line)
  if buff:
    yield "\n".join(buff)

def blocks2(text):
  """Only non-comment blocks *between* comments"""
  buff = None
  for line in text.split('\n'):
    if line.startswith('#'):
      if buff is None:
        buff = []
      if buff:
        yield "\n".join(buff)
        buff = []
    else:
      if buff is not None:
        buff.append(line)

for block in blocks2(sample):
  print "Block:\n%s" % (block,)

产地：

Block:
...
893.270609 1092.179289 184.692319
907.682255 1048.809187 112.538457
...
Block:
...
893.243290 1091.395104 184.726720
907.682255 1048.809187 112.538457
...

Answer 2

data.txt中：

123456
1234
# 0 867.691994 855.172889 279.230411 -78.951239 55.994189 -164.824148
# 0 872.477810 854.828159 279.690170 -78.950558 55.994391 -164.823700
...
893.270609 1092.179289 184.692319
907.682255 1048.809187 112.538457
...
# 0 877.347791 854.481104 280.214892 -78.949869 55.994596 -164.823240
...
893.243290 1091.395104 184.726720
907.682255 1048.809187 112.538457
...
# 0 882.216053 854.135168 280.745489 -78.948443 55.996206 -164.821887
1234
12345

程序：

with open('data.txt') as f:
    lines=[x.strip() for x in f if x.strip()]
    for i,x in enumerate(lines):  #loop to find the first comment line
        if x.startswith('#'):
            ind=i
            break
    for i,x in enumerate(lines[::-1]): #loop to find the first comment line from the end
        if x.startswith('#'):
            ind1=i
            break
    for x in lines[ind+1:-ind1-1]:
        if not x.startswith('#'):
            print x

<强>输出：

...
893.270609 1092.179289 184.692319
907.682255 1048.809187 112.538457
...
...
893.243290 1091.395104 184.726720
907.682255 1048.809187 112.538457
...

Python：需要提示从文本文件中读取数据块

2 个答案: