How to declare and write a script with hash tables on windows and linux

• Hash tables with powershell on windows

  Declaration:
  $states=@{“Alberta” = “Calgary”; “British Columbia” = “Vancouver”; “Ontario” = “Toronto” ; “Quebec” = “Montreal”}

  Name _____	Value _______
  Alberta	Calgary
  British Columbia	Vancouver
  Ontario	Toronto
  Quebec	Montreal

  Add new key-value in hashtable:
  $states.Add(“Manitoba”,”Winnipeg”)

  Remove key-value in hashtable:
  $states.Remove(“Manitoba”,”Winnipeg”)
  Change value in hashtable:
  $states.Set_Item(“Ontario”,”Ottawa”)
  Retrieve value in hashtable:
  $states.Get_Item(“Alberta”)
  Find key in hashtable:
  $states.ContainsKey(“Alberta”)
  Find Value in hashtable:
  $states.ContainsValue(“Calgary”)
  Count items in hashtable:
  $states.Count
  Sort items by Name in hashtable:
  $states.GetEnumerator() | Sort-Object Name -descending
  Sort items by Value in hashtable:
  $states.GetEnumerator() | Sort-Object Value -descending

• Hash tables with perl on linux or windows

   
  Declaration:
  my %hash = (); #Initialize a hash
  my $hash_ref = {}; # Initialize a hash reference. ref will return HASH
  Clear (or empty) a hash
  for (keys %hash)
  {
  delete $hash{$_};
  }
  Clear (or empty) a hash reference
  for (keys %$href)
  {
  delete $href->{$_};
  }
  Add a key/value pair to a hash
  $hash{ ‘key’ } = ‘value’; # hash
  $hash{ $key } = $value; # hash, using variables
  Using Hash Reference
  $href->{ ‘key’ } = ‘value’; # hash ref
  $href->{ $key } = $value; # hash ref, using variables
  Add several key/value pairs to a hash
  %hash = ( ‘key1’, ‘value1’, ‘key2’, ‘value2’, ‘key3’, ‘value3’ );
  %hash = (
  key1 => ‘value1’,
  key2 => ‘value2’,
  key3 => ‘value3’,
  );

  Copy a hash
  my %hash_copy = %hash; # copy a hash
  my $href_copy = $href; # copy a hash ref
  Delete a single key/value pair
  delete $hash{$key};
  delete $hash_ref->{$key};

Hash tables with python on linux or windows

Hash tables are called dictionary in python.
Declaration:
dict = {‘Name’: ‘Zara’, ‘Age’: 7, ‘Class’: ‘First’}
Accessing Values
print “dict[‘Name’]: “, dict[‘Name’]
print “dict[‘Age’]: “, dict[‘Age’]
Output:
dict[‘Name’]: Zara
dict[‘Age’]: 7
Updating Dictionary
dict = {‘Name’: ‘Zara’, ‘Age’: 7, ‘Class’: ‘First’}

dict[‘Age’] = 8; # update existing entry
dict[‘School’] = “DPS School”; # Add new entry
Delete Dictionary Elements
#!/usr/bin/python

dict = {‘Name’: ‘Zara’, ‘Age’: 7, ‘Class’: ‘First’}

del dict[‘Name’]; # remove entry with key ‘Name’
dict.clear(); # remove all entries in dict
del dict ; # delete entire dictionary

Source:

1. https://technet.microsoft.com/en-us/library/ee692803.aspx
2. http://www.cs.mcgill.ca/~abatko/computers/programming/perl/howto/hash/
3. http://www.tutorialspoint.com/python/python_dictionary.htm