在Python中连接file.write()中的字符串?

时间:2013-02-10 20:59:02

标签: python file concatenation

我正在尝试在Python 2.7.3中编写一个脚本,该脚本可以从Excel电子表格中获取.csv文件并将其转换为适合LaTeX表格的格式。所以我想读取一个文件,并将数据写入一个新的文本文件,但用逗号替换任何逗号,并在每行的末尾附加一个双反斜杠。

例:
输入

A1,A2,A3  
B1,B2,B3  
C1,C2,C3

期望输出

A1 & A2 & A3 \\
B1 & B2 & B3 \\
C1 & C2 & C3 \\

这就是我现在所拥有的:

old_file = open(selected_file, "r")
new_file = open("texified_" + selected_file.replace("csv","txt"), "w")
#Creates new file with format texified_selected_file.txt

for line in old_file:
    new_file.write(line.replace(",", " & ") + r" \\")

new_file.close()
old_file.close()

现在它正确地用符号替换逗号,但不添加双反斜杠。我认为这是因为反斜杠具有特殊含义,但即使将其作为原始字符串,它仍然无效。但它确实将它添加到最后一行的末尾。

实际输出

A1 & A2 & A3   
B1 & B2 & B3  
C1 & C2 & C3 \\

2 个答案:

答案 0 :(得分:1)

发生这种情况可能是因为文件中每行末尾都有newline,而不是last line的末尾。

您可以在添加//之前尝试剥离它,然后单独添加换行符: -

import os
ls = os.linesep

for line in old_file:
    new_file.write(line.replace(",", " & ").rstrip() + r' \\ ' + ls)

答案 1 :(得分:0)

我不确定您的代码(或输入数据)是否有问题,但我可能会这样做(可能不那么详细):

for line in old_file:
    line = line.strip()     # remove newline/whitespace from begin and end of line
    line = line.split(',')  # get comma-separated values
    line = " & ".join(line) # make it ampersand-separated values
    line += r" \\"          # add latex line break
    line += "\n"            # add file line break
    new_file.write(line)

或者这样:

import jinja2

# define the latex template
template_str = r"""
\documentclass{article}
\begin{document}
\begin{table}
  \centering
  \begin{tabular}{ccc}
%{ for line in table %} %{{line[0]%}} & %{{line[1]%}} & %{{line[2]%}} \\ 
%{ endfor %}
  \end{tabular}
\end{table}
\end{document}

"""

# initialize the rendering engine
renderer = jinja2.Environment(
  block_start_string = '%{',
  block_end_string = '%}',
  variable_start_string = '%{{',
  variable_end_string = '%}}'
)
template = renderer.from_string(template_str)

# bring the data array into shape
lines = [line.strip().split(',') for line in old_file]

# generate the tex source code
with open("test.tex", 'w+') as f:
  f.write(template.render(table=lines))

另请查看这些资源: