Python

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Data Types

 
int 1234
>>> type(1234)
<class 'int'>
float 55.50
>>> type(55.50)
<class 'float'>
complex
>>> type(6+4j)
<class 'complex'>
string hellow
>>> type("hello")
<class 'str'>
Square list [1,2,3,4]
>>> type([1,2,3,4])
<class 'list'>
Round tuple (1,2,3,4)
>>> type((1,2,3,4))
<class 'tuple'>
Curly dict {1:"one", 2:"two", 3:"three"}
>>> type({1:"one", 2:"two", 3:"three"})
<class 'dict'>


Python version of a perl hash

import collections

; def tree() : return collections.defaultdict(tree)

hash = tree()

hash[['outer_key']][['inner key']] = "value"


; if not bool(hash) : print "Hash is empty"
; else : print "Hash has some data"

Strings

  • Use "'{0}' is longer than '{1}'".format(name1, name2)
  • The new-style {} formatting uses {} codes and the .format method
  • 'It will cost ${0} dollars.'.format(95)
  • The old-style % formatting uses % codes for formatting:
  • 'It will cost $%d dollars.' % 95
  • Note that with old-style formatting, you have to specify multiple arguments using a tuple:
  • '%d days and %d nights' % (40, 40)

The 'new' / safe way to concatenate strings in a print statement

print("%s is %d years old." % (name, age))

XML

https://www.datacamp.com/community/tutorials/python-xml-elementtree


Update Modules

sudo python3 -m pip list --outdated --format=freeze | grep -v '^\-e' | cut -d = -f 1  | xargs -n1 sudo python3 -m pip install -U