Python 各种常用小功能

print后不换行

就是在命令后面加一个逗号。

print this,

当然这样写出来的代码到了3.3就不太管用了。所以还是老老实实用转义符吧,‘\r’

两列数字点乘

当然直接可以变成numpy.array然后乘起来，但如果不想为了这个小函数就加入一个依赖，那就这样：

from operator import mul

def dot(a_list, b_list):
    return map(mul, a_list, b_list)

将当前的时间输出成seconds from epochtime

import time, datetime
time.mktime(datetime.datetime.now().timetuple())

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PDF merging without tears

I guess nobody needs a cumbersome Acrobat software to merge PDF files. And when things gets a little bit more complex, manually merging hundreds of PDFs can be a PIAS.

Use this:

from PyPDF2 import PdfFileMerger, PdfFileReader
import os


filenames = ["1.pdf", "2.pdf"]
merger = PdfFileMerger()
for filename in filenames:
    merger.append(PdfFileReader(file(os.path.join(os.getcwd(), filename), 'rb')))
merger.write(os.path.join(os.getcwd(), "output.pdf"))

It works like magic. Put this .py file to the folder where you would like to have some PDFs merged, change filenames, and modify this script. Life is instantly easier.

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