Question

我有一个大文本文件，如小例子：

fit c3 start=1455035 step=1
2.000000
2.000000
2.000000
2.000000
2.000000
2.000000
fit c2 start=5195348 step=1
1.000000
1.000000
1.000000
1.000000
1.000000
fit c4 start=6587009 step=1
10.000000
10.000000
10.000000
10.000000
10.000000

我想尝试这样的事情：

fit c3 start=1455035 step=1
12.000000
1.000000
1.000000
1.000000
1.000000
1.000000
fit c2 start=5195348 step=1
5.000000
1.000000
1.000000
1.000000
1.000000
fit c4 start=6587009 step=1
50.000000
1.000000
1.000000
1.000000
1.000000

每个文本文件后跟一些数字行。正如您在输出中看到的那样，我希望将每个组的第一个数字替换为同一文本行（在同一组中）之下的所有数字的总和，并将其余数字替换为1.000000。并写入一个新文件。

我实际上在python中尝试了以下代码，但没有返回我想要的内容：

infile = open("file.txt", "r")
for line in infile:
    if line startswith"fit":
        for l in len(line):
            line[l] = line + line[l+1]

Answer 1

它既不是最优雅也不是最有效的方式，但它可能会让你对你需要做的事情有所了解：

with open("test.txt", "r") as infile:

    tempList = []        #Auxiliary list for number storage
    sums = []            #Stores the numbers of each fit heading
    fits = []            #Stores the 'fit' headings
    for line in infile:
        print(line)
        if not line.find("fit")==-1:
            fits.append(line)
            sums.append(tempList)
            tempList = []
        else:
            tempList.append(float(line.replace("\n","")))
            print(tempList)
    sums.append(tempList)
    sums.remove([])


for i in sums:
    i[0] = sum(i[0:])
    for j in range(1,len(i)):
        i[j] /= i[j]

print(fits)
print(sums)

with open("test2.txt", "w") as outFile:

    for i in range(len(fits)):
        outFile.write(fits[i])
        outFile.write("\n".join(str(j) for j in sums[i]))
        outFile.write("\n")

输出文件test2.txt包含以下内容：

fit c3 start=1455035 step=1
12.0
1.0
1.0
1.0
1.0
1.0
fit c2 start=5195348 step=1
5.0
1.0
1.0
1.0
1.0
fit c4 start=6587009 step=1
50.0
1.0
1.0
1.0
1.0

Answer 2

# Dictionary to store the "header" line as key
# And values will be the "sublines" you are changing
groups = {}

# First, get positions of "fit" lines
with open('file.txt', 'r') as f:
    for line in f:
        if line.startswith('fit'):
            current = line # the current "header" ("fit" line)
            groups[current] = []
        else:
            # Need to convert from 'str' to 'float'
            groups[current].append(float(line.strip()))

# Now sum and pad with 1.0
for header in groups:
    # Fill with 1.0 by adding 2 lists
    # First list is length 1 and contains only the sum of the original
    # Second list is length first - 1 and is all 1.0
    groups[header] = [sum(groups[header])] + [float(1)] * (len(groups[header]) - 1)

# Then rewrite to file
with open('file.txt', 'w') as f:
    for header in groups:
        f.write(header) # May need to add a '\n' if not present in file orignally
        for num in groups[header]:
            # Convert 'float' back to 'str' with newline
            f.write('{!s}\n'.format(num))

Answer 3

一种方法是使用itertools模块groupby和chain +列表理解

infile = open("file.txt", "r")
from itertools import groupby,chain
list_grp = [list(g) for k,g in groupby([i.strip() for i in infile.readlines()], lambda x:'fit' in x)]
for i in chain(*[[i[0]] if 'fit' in i[0] else list(chain(*[[sum(map(float,i))],[1.0 for i in i]])) for i in list_grp]):
    print (i)

输出：

fit c3 start=1455035 step=1
12.0
1.0
1.0
1.0
1.0
1.0
1.0
fit c2 start=5195348 step=1
5.0
1.0
1.0
1.0
1.0
1.0
fit c4 start=6587009 step=1
50.0
1.0
1.0
1.0
1.0
1.0

Answer 4

你也可以用熊猫来实现这个目标：

<强>设置

import pandas as pd

def is_float(x):
    try:
       float(x)
       return True
    except ValueError:
       return False

def to_float(x):
    if is_float(x):
       return float(x)
    else:
       return x

data = pd.read_csv(file_path, header=None, converters={0:to_float}) # line 1
is_numeric_value = lambda x: not is_float(x)
condition = data[0].map(is_numeric_value)

主要

titles = data.loc[condition] title_count = len(titles.index) # count of titles for i in xrange(title_count): ind = titles.index[i] if (i+1) != len(titles.index): next_ind = titles.index[i+1] data.iat[ind+1,0]=data.iloc[ind+2:next_ind].values.sum() else: data.iat[ind+1,0]=data.iloc[ind+2:].values.sum() # line 2

<强>输出

c5d.to_csv(file_path, header=None, index=False) # line 3

你可以通过用.txt替换.csv来将csv文件转换为txt。

P.S。这是假设你有一个包含多个部分的大文件（每个部分是标题+数字行）;如果您在一个文件中有一个部分，那么除了is_float和to_float之外，您可以在上面替换第1行，第2行和第3行。

在python中用text文件替换不同值的行

4 个答案: