{"id":644,"date":"2014-01-21T14:33:30","date_gmt":"2014-01-21T21:33:30","guid":{"rendered":"http:\/\/somethingk.com\/main\/?p=644"},"modified":"2014-01-21T14:42:05","modified_gmt":"2014-01-21T21:42:05","slug":"python-optionparser","status":"publish","type":"post","link":"https:\/\/somethingk.com\/main\/python-optionparser\/","title":{"rendered":"Python OptionParser"},"content":{"rendered":"

I love when code makes life easier. However, if you don’t know what the code does… life isn’t so easy now. That’s why we have man<\/a> pages!<\/p>\n

\"\"<\/a>
In honor of those “man” pages…<\/figcaption><\/figure>\n

Except building a man page for a script and handling the “-h” argument from a command prompt can be tedious.<\/p>\n

Python has a really cool library called optparse, that includes the ability to make a “help” output for a script along with argument handling. You know\u00a0how nice that is to have a library take care of the whole argument handling? Very nice! I would hate to use regular expressions to try and parse a list of\u00a0<\/span>command line inputs.<\/span><\/p>\n

If my blog posts about the language haven’t made this obvious already, I really love Python. It does have faults because it is not a type-safe language and in some\u00a0circumstances that can be an issue. I’ll go into detail at a later time. Ideally, it is best to have both type-safe and dynamic type languages in your repertoire of tools.<\/span><\/p>\n

Anyways, back to Optparse. It’s basically self-explanatory.<\/p>\n

Import OptionParser.<\/p>\n

from optparse import OptionParser<\/pre>\n
Next, setup an OptionParser object.<\/p>\n
parser = OptionParser()<\/pre>\n
Give it some flags or parameter options. You do not have to create a -h or help option, this will be created for you automatically. Below is a template for creating an option.<\/p>\n
parser.add_option(\"-<OPTION LETTER>\", \"--<OPTION NAME>\", dest=\"<VARIABLE NAME TO STORE OPTION CONTENT>\", default=<DEFAULT VALUE>, help=\"<HELP TEXT>\")<\/code><\/p>\n
Each option creates a possible input parameter that user’s can specify. If you do not want the user to have to input a value, maybe a flag is more your style.<\/p>\n
A flag is a true or false notification that does not require additional user input. If a flag is present do something, if not do something else. To create a flag, set\u00a0the default option to true or false and add “action=”store_true” or add “action=”store_false”\u00a0in order to simulate a flag option. When you want the flag to turn a statement true set\u00a0“action=”store_true” and “default=False” and the exact opposite for a flag to turn something false.\u00a0<\/span><\/p>\n
To help clarify things, I wrote up a fun example below.<\/p>\n
Example<\/strong><\/p>\n
The below was coded for Python 2.7 and saved to a file called fun.py.<\/p>\n
from optparse import OptionParser
\nimport os, time<\/p>\n
def somethingCool(dazzling):
\n    print \"Something Cool\"
\n    if dazzling:
\n        print \"\\n~*~*~*~*~*~*~\"+dazzling+\"~*~*~*~*~*~*~\"<\/p>\n
def somethingStupid(dazzling):
\n    print \"Something Stupid...\"
\n    if dazzling:
\n        print \"\\n--------------\"+dazzling+\"--------------\"<\/p>\n
def main():
\n    parser = OptionParser() #Help menu options
\n    parser.add_option(\"-c\", \"--cool\", action=\"store_true\", dest=\"cool\", default=False, help=\"Do something cool!\")
\n    parser.add_option(\"-s\", \"--stupid\", action=\"store_true\", dest=\"stupid\", default=False, help=\"Do something stupid...\")
\n    parser.add_option(\"-d\", \"--dazzling\", dest=\"dazzling\", default=None, help=\"Add this dazzling text to the cool or stupid thing.\")
\n    (options, args) = parser.parse_args()
\n    if options.cool:
\n        somethingCool(options.dazzling)
\n    elif options.stupid:
\n        somethingStupid(options.dazzling)
\n    else:
\n        print \"Lame, you selected nothing...\"<\/p>\n
if __name__ == \"__main__\":
\n    main()<\/code><\/p>\n
Explanation<\/strong><\/p>\n
OptionParser will automatically create a help option (-h) for you. Here is what the help screen looks like for my code example:<\/p>\n
\"Screen<\/a><\/p>\n
Basically, if I call the script with the -c flag, something cool will happen.<\/p>\n
python fun.py -c<\/pre>\n
If I call the script with the -s flag, something stupid will happen.<\/p>\n
python fun.py -s<\/pre>\n
\"Screen<\/a><\/p>\n
If I call the script with the -d <TEXT> and a flag something will happen with text.<\/p>\n
python fun.py -c -d \"My Blog at Somethingk.com\"\r\n\r\n\"Screen<\/a><\/pre>\n
If I don’t provide a -s or a -c flag, the code insults me… A flag isn’t required but nothing else will happen if one isn’t given.<\/p>\n
\"Screen<\/a><\/p>\n
Check out http:\/\/docs.python.org\/2\/library\/optparse.html<\/a> for more details. Have fun!<\/p>\n","protected":false},"excerpt":{"rendered":"
I love when code makes life easier. However, if you don’t know what the code does… life isn’t so easy now. That’s why we have man pages! Except building a man page for a script and handling the “-h” argument from a command prompt can be tedious. Python has a really cool library called optparse, that includes the ability to […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[72],"tags":[157,155,156,153],"class_list":["post-644","post","type-post","status-publish","format-standard","hentry","category-python","tag-argument-handling","tag-optionparser","tag-optparse","tag-python-2-7"],"_links":{"self":[{"href":"https:\/\/somethingk.com\/main\/wp-json\/wp\/v2\/posts\/644","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/somethingk.com\/main\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/somethingk.com\/main\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/somethingk.com\/main\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/somethingk.com\/main\/wp-json\/wp\/v2\/comments?post=644"}],"version-history":[{"count":14,"href":"https:\/\/somethingk.com\/main\/wp-json\/wp\/v2\/posts\/644\/revisions"}],"predecessor-version":[{"id":662,"href":"https:\/\/somethingk.com\/main\/wp-json\/wp\/v2\/posts\/644\/revisions\/662"}],"wp:attachment":[{"href":"https:\/\/somethingk.com\/main\/wp-json\/wp\/v2\/media?parent=644"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/somethingk.com\/main\/wp-json\/wp\/v2\/categories?post=644"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/somethingk.com\/main\/wp-json\/wp\/v2\/tags?post=644"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}