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Python dictionary for quick look ups

Using a dictionary in Python, you can avoid the need for a loop in your program to search out elements in a collection. Suppose, for example, you have a list of people and a list of their countries of origin, you could look up individuals like this:

names = ["Jesus","Marc","Michal","Graham"]
places = ["Spain","USA","Poland","UK"]
for x in range(len(names)):
  if names[x] == "Marc": print places[x]
  if names[x] == "Graham": print places[x]


But with a dictionary, it is both easier and faster:

who = {"Jesus":"Spain", "Marc":"USA", "Michal":"Poland","Graham":"UK"}
print who["Michal"]
print who["Jesus"]


In effect, a dictionary is a database table with two columns ...
(written 2007-04-12)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
Y107 - Python - Dictionaries
  [4668] Sorting a dict in Python - (2016-04-01)
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  [4469] Sorting in Python 3 - and how it differs from Python 2 sorting - (2015-04-20)
  [4409] Setting up and using a dict in Python - simple first example - (2015-01-30)
  [4029] Exception, Lambda, Generator, Slice, Dict - examples in one Python program - (2013-03-04)
  [4027] Collections in Python - list tuple dict and string. - (2013-03-04)
  [3934] Multiple identical keys in a Python dict - yes, you can! - (2012-11-24)
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  [3464] Passing optional and named parameters to python methods - (2011-10-04)
  [2994] Python - some common questions answered in code examples - (2010-10-10)
  [2986] Python dictionaries - reaching to new uses - (2010-10-05)
  [2915] Looking up a value by key - associative arrays / Hashes / Dictionaries - (2010-08-11)
  [2368] Python - fresh examples of all the fundamentals - (2009-08-20)
  [1145] Using a list of keys and a list of values to make a dictionary in Python - zip - (2007-04-13)
  [955] Python collections - mutable and imutable - (2006-11-29)
  [103] Can't resist writing about Python - (2004-10-29)


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