1 00:00:00,340 --> 00:00:03,720 Okay, so now that we've worked with standard data values, 2 00:00:03,720 --> 00:00:08,340 variables, and string values, let's talk about custom object data. 3 00:00:08,340 --> 00:00:11,780 The advantage here is that we want to be able to create something 4 00:00:11,780 --> 00:00:14,750 custom that matches the type of data that we're using. 5 00:00:14,750 --> 00:00:19,240 Now, a custom data object could be an array. 6 00:00:19,240 --> 00:00:21,210 It could be a hash table. 7 00:00:21,210 --> 00:00:24,440 It could also be a custom object. 8 00:00:24,440 --> 00:00:26,160 So, what are arrays? 9 00:00:26,160 --> 00:00:29,720 Well, an array is a list or collection of values or objects, 10 00:00:29,720 --> 00:00:33,660 and we've seen some of these already where they're a comma‑separated list. 11 00:00:33,660 --> 00:00:39,880 Most important thing here, arrays only contain values, no properties. 12 00:00:39,880 --> 00:00:43,760 So there's no something on an item dot something as a property. 13 00:00:43,760 --> 00:00:45,260 That doesn't exist. 14 00:00:45,260 --> 00:00:47,410 Now to create an array, 15 00:00:47,410 --> 00:00:53,640 empty arrays are created by using the @ and then parentheses. 16 00:00:53,640 --> 00:00:56,760 You can have comma‑separated lists as arrays, 17 00:00:56,760 --> 00:01:02,580 and then, of course, the Write‑Output command can also create string arrays. 18 00:01:02,580 --> 00:01:04,870 So if you're just using string arrays of data, 19 00:01:04,870 --> 00:01:08,040 there's already a command that can help us do that. 20 00:01:08,040 --> 00:01:14,940 So to create an array, an empty array, it's going to be $variable = @(). 21 00:01:14,940 --> 00:01:20,090 That will create an array, and then we can add values into that array. 22 00:01:20,090 --> 00:01:23,430 We could create an array with existing values. 23 00:01:23,430 --> 00:01:26,220 So I'm using January, February, March, April, May, June. 24 00:01:26,220 --> 00:01:29,910 They are in text values and comma‑separated, 25 00:01:29,910 --> 00:01:34,240 so that populates my variable array automatically. 26 00:01:34,240 --> 00:01:39,890 I could create an array with text values, but not use the @ and parentheses. 27 00:01:39,890 --> 00:01:43,840 That would create a standard string array. 28 00:01:43,840 --> 00:01:46,820 And then I can also use the Write‑Output to do the same thing. 29 00:01:46,820 --> 00:01:48,660 So we're not using the @(), 30 00:01:48,660 --> 00:01:52,460 we're just using Write‑Output and these values with separations, 31 00:01:52,460 --> 00:01:55,030 and that will create an array. 32 00:01:55,030 --> 00:01:57,520 Now, of course, once we have the arrays, 33 00:01:57,520 --> 00:02:01,940 then, of course, we need to look at how we retrieve array items. 34 00:02:01,940 --> 00:02:06,380 So I'm using $variable = @() and then January, 35 00:02:06,380 --> 00:02:07,520 February, March, April, May, June. 36 00:02:07,520 --> 00:02:09,720 If I wish to retrieve a value, 37 00:02:09,720 --> 00:02:13,510 the most standard and easiest way is to use what's called Offset. 38 00:02:13,510 --> 00:02:17,970 Offset will be the unique ID or placement of that value. 39 00:02:17,970 --> 00:02:23,340 So if I do $variable[0], that will get me January. 40 00:02:23,340 --> 00:02:28,050 If I do $variable[2], that will give me March. 41 00:02:28,050 --> 00:02:30,840 It always begins at 0. 42 00:02:30,840 --> 00:02:34,650 I can access an array item using multiple offsets as well, 43 00:02:34,650 --> 00:02:37,910 so I could say get me variable offset 0, 44 00:02:37,910 --> 00:02:42,660 January, 1, February, 4, April. 45 00:02:42,660 --> 00:02:45,570 That would actually get April or May. 46 00:02:45,570 --> 00:02:48,340 That would give me those three values. 47 00:02:48,340 --> 00:02:52,810 I can access the array items using a range operator as an offset. 48 00:02:52,810 --> 00:02:55,330 So just like we did previously where we populated a 49 00:02:55,330 --> 00:02:59,260 variable with 1 to 10 by using 1..10, 50 00:02:59,260 --> 00:03:02,280 I could do the same here and say go and get me the 51 00:03:02,280 --> 00:03:05,760 range operator offset of 2 to 5, 52 00:03:05,760 --> 00:03:09,510 which would obviously take me over to not January, 53 00:03:09,510 --> 00:03:13,430 not February, but start at March and go upwards. 54 00:03:13,430 --> 00:03:18,020 Now we also often want to iterate array items. 55 00:03:18,020 --> 00:03:22,340 So not only are we just taking odd things out and getting single values, 56 00:03:22,340 --> 00:03:23,870 we may want to iterate. 57 00:03:23,870 --> 00:03:25,530 So once again, we create the variable. 58 00:03:25,530 --> 00:03:29,440 And you can see we're using a ForEach‑Object. 59 00:03:29,440 --> 00:03:31,840 So this means I'm going into the variable. 60 00:03:31,840 --> 00:03:33,370 I'm using a pipe command, 61 00:03:33,370 --> 00:03:36,670 which we've talked about in the past where we're piping whatever's in the 62 00:03:36,670 --> 00:03:40,930 variable to the next piece and saying ForEach‑Object, 63 00:03:40,930 --> 00:03:43,550 and then I'm just literally writing out the value, 64 00:03:43,550 --> 00:03:46,160 so the month is whatever that would be. 65 00:03:46,160 --> 00:03:49,350 And you can see we're using something called $PSItem. 66 00:03:49,350 --> 00:03:56,250 That is a standard PowerShell property or variable that's created by 67 00:03:56,250 --> 00:04:00,840 PowerShell for the output of a ForEach‑Object loop. 68 00:04:00,840 --> 00:04:04,770 We can do this differently by using a foreach statement that we've used before, 69 00:04:04,770 --> 00:04:08,070 so we can say foreach item in that variable and then 70 00:04:08,070 --> 00:04:10,230 go ahead and write the values out. 71 00:04:10,230 --> 00:04:12,600 I could also use the ForEach method. 72 00:04:12,600 --> 00:04:16,220 So knowing that the variable contains the values, 73 00:04:16,220 --> 00:04:20,540 that allows me to say ForEach and then write those values out. 74 00:04:20,540 --> 00:04:21,320 And then, of course, 75 00:04:21,320 --> 00:04:25,780 our other option is to use a for loop to go through the values. 76 00:04:25,780 --> 00:04:30,260 Now you can see the code difference here, single lines to multiple lines. 77 00:04:30,260 --> 00:04:31,170 So, for example, 78 00:04:31,170 --> 00:04:34,660 that last one is foreach item equals 0 if the item 79 00:04:34,660 --> 00:04:36,380 is less than the variable count. 80 00:04:36,380 --> 00:04:41,280 So if there's seven things in there, it will iterate seven times and then stop. 81 00:04:41,280 --> 00:04:47,340 Now, another version of arrays, I suppose, is a hash table. 82 00:04:47,340 --> 00:04:51,040 So the hash table is a data structure, very much like an array, 83 00:04:51,040 --> 00:04:54,250 except you can store every value, an object, 84 00:04:54,250 --> 00:04:55,580 using a key. 85 00:04:55,580 --> 00:04:59,310 So hash tables only contain values, not properties. 86 00:04:59,310 --> 00:05:03,540 They are basically a key value store. 87 00:05:03,540 --> 00:05:05,470 So when we look at the hash tables, 88 00:05:05,470 --> 00:05:10,650 they're also known as a dictionary or what's called an associative array, 89 00:05:10,650 --> 00:05:15,840 the data structure that stores one or more key value pairs. 90 00:05:15,840 --> 00:05:21,240 So there will be a unique key that represents the value. 91 00:05:21,240 --> 00:05:26,940 Keys and values in hash tables are defined as .NET objects. 92 00:05:26,940 --> 00:05:33,440 And then, of course, it's an efficient way of finding and retrieving data. 93 00:05:33,440 --> 00:05:38,260 Now to create a hash table, we once again start with the @ as before. 94 00:05:38,260 --> 00:05:43,660 You wrap the hash table in braces, so you can see we've got our combination here. 95 00:05:43,660 --> 00:05:50,440 You can use an = to separate each key from its value, 96 00:05:50,440 --> 00:05:57,640 and then you use a semicolon or a line break to separate the key value pairs. 97 00:05:57,640 --> 00:06:00,240 So let's look at how we create the hash table. 98 00:06:00,240 --> 00:06:03,080 Well, first off, I'm going to create my empty hash table. 99 00:06:03,080 --> 00:06:04,550 Now don't get confused here. 100 00:06:04,550 --> 00:06:09,420 When we created the array, we used @, and then we used parentheses. 101 00:06:09,420 --> 00:06:16,040 A hash table is an @, and then what I refer to as the squirrelly brackets. 102 00:06:16,040 --> 00:06:20,600 What we can then do is create what is the key and values. 103 00:06:20,600 --> 00:06:27,840 So you can see here I've got Month = 5; Name = May; Season = Spring. 104 00:06:27,840 --> 00:06:31,750 I could go a little bit further here, and I could create an ordered hash table, 105 00:06:31,750 --> 00:06:40,530 which would order those values by the keys and values. 106 00:06:40,530 --> 00:06:42,860 Now to display values from the hash tables, 107 00:06:42,860 --> 00:06:46,400 we first store the hash table in a variable, 108 00:06:46,400 --> 00:06:51,740 so we basically say $variable name, and then press Enter. 109 00:06:51,740 --> 00:06:54,990 We can then use the dot notation to display all of the 110 00:06:54,990 --> 00:06:58,640 keys or the values inside that variable. 111 00:06:58,640 --> 00:07:03,420 So, for example, $variable.keys would return the key values, 112 00:07:03,420 --> 00:07:07,640 whereas $variable.values would return the values. 113 00:07:07,640 --> 00:07:10,430 Each key name is also a property. 114 00:07:10,430 --> 00:07:15,350 So, for example, $variable.Month, which would be one of the values, 115 00:07:15,350 --> 00:07:17,540 would return a value. 116 00:07:17,540 --> 00:07:21,040 I can also do that by using $variable and then square 117 00:07:21,040 --> 00:07:25,000 brackets and in text type in the value or the property name 118 00:07:25,000 --> 00:07:27,350 that we wish to retrieve the value for. 119 00:07:27,350 --> 00:07:29,770 So to iterate a hash table, 120 00:07:29,770 --> 00:07:33,440 let's say we create a country population hash table here, 121 00:07:33,440 --> 00:07:36,470 so I've got $variable equals a hash table, 122 00:07:36,470 --> 00:07:41,100 and in the hash table is four countries with their population. 123 00:07:41,100 --> 00:07:47,820 To iterate all the keys and values, I could use a ForEach‑Object loop. 124 00:07:47,820 --> 00:07:50,560 So I'm saying $variable.keys. 125 00:07:50,560 --> 00:07:57,130 So for each key, loop inside of it, and then the output of that will be, 126 00:07:57,130 --> 00:08:01,250 you can see I'm using a different syntax here where in the string 127 00:08:01,250 --> 00:08:04,370 values I have a 0 and a 1 in squirrelly brackets. 128 00:08:04,370 --> 00:08:08,330 That means I'm going to fill those values with something else, 129 00:08:08,330 --> 00:08:10,000 and you can see the ‑f, 130 00:08:10,000 --> 00:08:14,750 which basically says format the output of this in this way. 131 00:08:14,750 --> 00:08:19,150 So I want a value, something, which would be the name of the country, 132 00:08:19,150 --> 00:08:23,040 has a population of something, which is the value. 133 00:08:23,040 --> 00:08:25,850 So what you can see here is because we're using a ForEach‑Object 134 00:08:25,850 --> 00:08:28,830 and we've already told it to iterate the keys, 135 00:08:28,830 --> 00:08:34,420 I don't need to call the key value because in the ForEach‑Object, 136 00:08:34,420 --> 00:08:35,840 it's iterating them anyway. 137 00:08:35,840 --> 00:08:38,110 So I can do $_, 138 00:08:38,110 --> 00:08:43,210 which will represent the names of the countries or the keys from the hash table. 139 00:08:43,210 --> 00:08:45,550 And then you'll see in the variable option, 140 00:08:45,550 --> 00:08:47,510 I've told it to go ahead and get the variable, 141 00:08:47,510 --> 00:08:51,840 and then all goes together in a Write‑Output. 142 00:08:51,840 --> 00:08:55,080 Now we can iterate all the keys doing just a standard for 143 00:08:55,080 --> 00:08:57,450 loop like a standard regular foreach loop. 144 00:08:57,450 --> 00:09:01,180 So I can say foreach key in the keys, output, 145 00:09:01,180 --> 00:09:04,640 format the same thing, and then output the value. 146 00:09:04,640 --> 00:09:10,240 So iterating a hash table is very much like Iterating an array. 147 00:09:10,240 --> 00:09:14,230 Now we have another type of object here called the PSCustomObject. 148 00:09:14,230 --> 00:09:19,960 So PSCustomObjects are a really simple and easy way to create structured data. 149 00:09:19,960 --> 00:09:32,240 A PSCustomObject is comprised of both properties and values. 150 00:09:32,240 --> 00:09:36,520 So a PSCustomObject is like a hash table, 151 00:09:36,520 --> 00:09:43,740 except it's strongly typed as what's referred to as a PSCustomObject. 152 00:09:43,740 --> 00:09:47,740 The properties are ordered by default. 153 00:09:47,740 --> 00:09:48,600 And then, of course, 154 00:09:48,600 --> 00:09:52,310 the PSCustomObject contains what's referred to as a NoteProperty. 155 00:09:52,310 --> 00:09:57,510 So this is the same as common PowerShell objects that are part of 156 00:09:57,510 --> 00:10:00,340 the core PowerShell construct in the language. 157 00:10:00,340 --> 00:10:02,470 Now to create a custom PSObject, 158 00:10:02,470 --> 00:10:06,380 we're going to use syntax that's very similar to what we've chosen before. 159 00:10:06,380 --> 00:10:10,000 So we're going to say $variable =, and then we're going to strongly type, 160 00:10:10,000 --> 00:10:12,370 so we're going to say [PSCustomObject]@, 161 00:10:12,370 --> 00:10:14,710 and then the squirrelly brackets, 162 00:10:14,710 --> 00:10:18,060 which will create us effectively the hash table, 163 00:10:18,060 --> 00:10:21,240 but it's a PSCustomObject. 164 00:10:21,240 --> 00:10:24,620 We can also create an empty one in a different way by using what's 165 00:10:24,620 --> 00:10:28,100 called New‑Object with a ‑TypeName of PSObject, 166 00:10:28,100 --> 00:10:30,130 so two ways of doing this. 167 00:10:30,130 --> 00:10:33,040 That's actually quite a common way of doing it as well. 168 00:10:33,040 --> 00:10:36,420 Now if I want to create and populate the custom object 169 00:10:36,420 --> 00:10:38,540 using the countries that we used before, 170 00:10:38,540 --> 00:10:43,260 you can see that I just adjust the variable and say PSCustomObject, 171 00:10:43,260 --> 00:10:47,440 and then it's still the same kind of text values. 172 00:10:47,440 --> 00:10:50,580 Now if I want to add items to the custom object, 173 00:10:50,580 --> 00:10:55,750 now I can because I have this ability to add to the PSCustomObject. 174 00:10:55,750 --> 00:10:59,240 So you can see here, I'm saying choose the variable, 175 00:10:59,240 --> 00:11:03,500 pipe it out, and say add a member to the PSCustomObject. 176 00:11:03,500 --> 00:11:08,530 And the ‑MemberType is a NoteProperty, and then give it a name and a value. 177 00:11:08,530 --> 00:11:14,840 And so I'm now adding Russia and Norway into the list of countries. 178 00:11:14,840 --> 00:11:17,630 Now what about if we want to retrieve those values? 179 00:11:17,630 --> 00:11:21,830 Well, we have our standard PSCustomObject. And this time, 180 00:11:21,830 --> 00:11:25,530 I could return all the PSCustomObject key value pairs by 181 00:11:25,530 --> 00:11:28,640 just typing out the variable itself. 182 00:11:28,640 --> 00:11:32,590 If I wanted to get the country, I now have the ability to do so. 183 00:11:32,590 --> 00:11:34,200 I can say $variable.Spain. 184 00:11:34,200 --> 00:11:39,640 That's it, and it would return the value. 185 00:11:39,640 --> 00:11:43,780 We also have the ability to test the PSCustomObjects. 186 00:11:43,780 --> 00:11:49,720 So the type comparison, which would be kind of IS and ISNOT, 187 00:11:49,720 --> 00:11:54,250 are used to determine if an object has a specific type. 188 00:11:54,250 --> 00:11:58,540 So I could say is it this type, is it not this type? 189 00:11:58,540 --> 00:12:00,250 So what does that look like in PowerShell? 190 00:12:00,250 --> 00:12:05,040 Well, $variable1 = to number 10, so it's not a strongly‑typed variable. 191 00:12:05,040 --> 00:12:09,550 $variable2 is equal to 10, but it's a string version of that one. 192 00:12:09,550 --> 00:12:14,120 And $variable1 I'm trying to convert to an integer, 193 00:12:14,120 --> 00:12:18,320 so I'm saying $variable1 is an integer. 194 00:12:18,320 --> 00:12:23,700 I could also say $variable1 ‑is $variable2.GetType(). 195 00:12:23,700 --> 00:12:27,740 So I'm trying to match it now and say are they the same? 196 00:12:27,740 --> 00:12:32,350 I've also got, well, $variable1, is it not an integer? 197 00:12:32,350 --> 00:12:34,040 So I can do that too. 198 00:12:34,040 --> 00:12:37,440 And then I can do ‑isnot $variable2.GetType. 199 00:12:37,440 --> 00:12:40,440 So that ‑is will allow me to check. 200 00:12:40,440 --> 00:12:41,580 Now, what does that look like, 201 00:12:41,580 --> 00:12:46,000 and what error messages do we get when we come back? We'll have a look at that in a moment as well.