sorting - Python3 Make tie-breaking lambda sort more pythonic? -


as exercise in python lambdas (just can learn how use them more properly) gave myself assignment sort strings based on other natural string order.

i scraped apache version number strings , came lambda sort them based on numbers extracted regexes. works, think can better don't know how improve it's more robust.

from lxml import html import requests import re  # send request page , parse list of html links jmeter_archive_url='https://archive.apache.org/dist/jmeter/binaries/' jmeter_archive_get=requests.get(url=jmeter_archive_url) page_tree=html.fromstring(jmeter_archive_get.text) list_of_links=page_tree.xpath('//a[@href]/text()')  # filter out non-md5s. there lot of links, , # it's more data needed exercise jmeter_md5_list=list(filter(lambda x: x.endswith('.tgz.md5'), list_of_links))  # here's 'magic' happens. use 2 different regexes rip first # , second number out of string , turn them integers. # return them in order grabbed them, allowing tie break. jmeter_md5_list.sort(key=lambda val: (int(re.search('(\d+)\.\d+', val).group(1)), int(re.search('\d+\.(\d+)', val).group(1)))) print(jmeter_md5_list)

this have desired effect, output is:

['jakarta-jmeter-2.5.1.tgz.md5', 'apache-jmeter-2.6.tgz.md5', 'apache-jmeter-2.7.tgz.md5', 'apache-jmeter-2.8.tgz.md5', 'apache-jmeter-2.9.tgz.md5', 'apache-jmeter-2.10.tgz.md5', 'apache-jmeter-2.11.tgz.md5', 'apache-jmeter-2.12.tgz.md5', 'apache-jmeter-2.13.tgz.md5']

so can see strings sorted order makes sense. lowest version first , highest version last. immediate problems see solution two-fold.

  • first, have create 2 different regexes numbers want instead of capturing groups 1 , 2. because know there no multiline lambdas, don't know how reuse single regex object instead of creating second.
  • secondly, works long version numbers 2 numbers separated single period. first element 2.5.1, sorted correct place current method wouldn't know how tie break 2.5.2, or 2.5.3, or string arbitrary number of version points.

so works, there's got better way it. how can improve this?

this not full answer, far along road one.

the return value of key function can tuple, , tuples sort naturally. want output key function be:

((2, 5, 1), 'jakarta-jmeter') ((2, 6), 'apache-jmeter') etc.

do note poor use case lambda regardless.


Comments

Post a Comment

Popular posts from this blog

c++ - Difference between pre and post decrement in recursive function argument -

i have following sample code used pre-decrement void function(int c) { if(c == 0) { return; } else { cout << "dp" << c << endl; function(--c); cout << c << endl; return; } } this function give output input 4 : dp3 dp2 dp1 dp0 0 1 2 3 but when use post decrement void function(int c) { if(c == 0) { return; } else { cout << "dp" << c << endl; function(c--); cout << c << endl; return; } } output goes in infinite loop dp4 can explain me in detail why happens ? this happens because function(c--) called same value of c , when finishes c decremented. recursively called, hence called same value no chance of return , hit stack overflow error. assume this, int x = 1, y = 0; y = x++ result y == 1 , x == 2. if y = ++x , bot x , y 2.
Read more

php - Nothing but 'run(); ' when browsing to my local project, how do I fix this? -

i added new project. made mistake in projectname.conf file in sites-available apache2, led me reinstalling apache2. after reinstalling , re-enabling projects on every page of every project .. <body> run(); </body> .. i've run composer update, restarted service, restarted pc, checked config files, tried disabling new project. there nothing in error log, , access.log: 127.0.0.1 - - [15/may/2015:01:40:47 +0200] "get / http/1.1" 304 181 "-" "mozilla/5.0 (x11; ubuntu; linux x86_64; rv:38.0) gecko/20100101 firefox/38.0" maybe i'm forgetting apache2 reinstall? don't think did different last time installed it. looks haven't setup php correctly. take @ this great guide , maybe you're forgetting link php config apache2.
Read more

php - How can I echo out this array? -

i don't know how go grabbing data in variable , put foreach loop. class tree{ private $info = array( array('name'=>'jim','state'=>'nu','company'=>'nu','phone'=>array('cell'=>'5615111111','office'=>'5611111111'),'email'=>array('primary'=>'exs@example.com','ex@there.com')), array('name'=>'joe smith','city'=>'phoenix','phone'=>'4805551111','email'=>'jsmith@some_email.com'), array('name'=>'john doe','city'=>'chandler','company'=>'doe co.','email'=>array('jdoe@gmail.com','personal'=>'email@email.com'),'phone'=>'6025550002') ); } if you're inside of class, can access private variable using $this->variablename . example, i...
Read more