Python memo using perl --format is convenient.

--Make a note of what you thought was python.

Variable expansion by%

--The equivalent of sprintf in perl can be achieved with% in python. It's easy and good.

>>> u"%s,%02d" % ('ABC',2)
'ABC,02'

There was also a format.

It seems that it can be expanded with {subscript}.

>>> "{0},{1}".format('ABC',2)
'ABC,2'

It seems that you can also specify a format like% 02d.

>>> "{0},{1:02d}".format('ABC',2)
'ABC,02'

Is it a list expansion?

――I will try to enter a variable instead of entering it directly.

>>> a = ['a','b','c']
>>> a
['a', 'b', 'c']
>>> "{0}_{1}_{2}".format(a)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
IndexError: tuple index out of range

• that? I got angry. --It seems that the variable a is written as \ * a.

>>> "{0}_{1}_{2}".format(*a)
'a_b_c'
>>> "{0}_{1}_{2}".format(*['a','b','c'])
'a_b_c'
>>> "{0}_{1}_{2}".format(*('t','u','p'))
't_u_p'

Convenient combination with dictionary type!

――Well, that's right up to this point, isn't it? ――But the combination with the dictionary type is convenient, it seems that you are using the template module only with this. ――It seems that you can write \ * as two variables, \ * \ * d.

>>> d={"name":"John","age":25}
>>> d
{'name': 'John', 'age': 25}
>>> "call me '{name}' , I'm {age}".format(**d) 
"call me 'John' , I'm 25"

--The Easy!

Example of dictionary type and format combination

――At this time, there are only dictionaries and arrays like JSON, so the range of applications is wide.

rss.py

# -*- coding: utf-8 -*-

import feedparser

qiita_dic = feedparser.parse('http://qiita.com/tags/python/feed.atom')

for entry in qiita_dic.entries:
    print(u"{title}\t{link}\t{published}\t{author}".format(**entry))

――It is the execution result, it is good to be able to do it in one line!

sh-3.2$ python rss.py
TensFlow Preferences Memo http://qiita.com/s_nakamura/items/b502fb29b3f6321a0403	2016-10-10T16:09:52+09:00	s_nakamura
I tried to make Othello AI with tensorflow without understanding the theory of machine learning ~ Part 1 ~ http://qiita.com/sasaco/items/3b0b8565d6aa2a640caf	2016-10-10T15:28:54+09:00	sasaco
[Personal notes]Python sequence type / mapping type http://qiita.com/RyoMa_0923/items/a714eb5dce24e9463c00	2016-10-10T13:16:19+09:00	RyoMa_0923
Let's summarize the Python coding standard PEP8(2)	http://qiita.com/sartan123/items/a74010b06f47792e7660	2016-10-10T11:55:54+09:00	sartan123
StackStorm :Develop pack with st2sdk http://qiita.com/unchemist/items/10046264d29fb7c7334b	2016-10-10T03:08:35+09:00	unchemist
Implement features like window replacement on Ubuntu http://qiita.com/fx-kirin/items/f41aaaeef9a5886cf87f	2016-10-10T00:50:32+09:00	fx-kirin
〜〜〜

With perl ...

――It looks like this, isn't it intuitive compared to format ...

sh-3.2$ perl -le '{my %d = ("name"=>"John","age"=>25);print sprintf("call me %s , Im %d",map {$d{$_}} ("name","age"))}'
call me John , Im 25