1 00:00:00,480 --> 00:00:03,260 Hello and welcome to this video. 2 00:00:03,360 --> 00:00:12,650 In this video I'll be talking to you about a very important concept in computer programming called variables. 3 00:00:12,960 --> 00:00:15,980 Variables are very important. 4 00:00:16,140 --> 00:00:24,250 They allow you to store various pieces of information that you can use for your application. 5 00:00:24,720 --> 00:00:34,020 If you look at big large applications like Facebook Instagram Twitter and a host of others they all 6 00:00:34,020 --> 00:00:38,960 use variables to store and retrieve information. 7 00:00:39,030 --> 00:00:47,400 Even your bank when you go to get some money from the bank or from the machine it all stores information 8 00:00:47,490 --> 00:00:49,320 and retrieves information. 9 00:00:49,320 --> 00:00:53,020 All of that is done using variables. 10 00:00:53,100 --> 00:00:55,680 So what is a variable. 11 00:00:55,680 --> 00:01:05,970 Variables basically is a holding container that is used to store a value that can be referenced as of 12 00:01:05,970 --> 00:01:08,220 when required. 13 00:01:08,430 --> 00:01:13,770 The value that the variable stores can vary. 14 00:01:13,770 --> 00:01:23,880 That means they can change hence the name Variable variables are parts of your computer's memory where 15 00:01:23,880 --> 00:01:34,150 information can be stored the variables on giving names in order to identify them. 16 00:01:34,180 --> 00:01:45,200 We then use the names to retrieve the information that the variable stores variables can hold values 17 00:01:45,650 --> 00:01:47,960 of different types. 18 00:01:48,110 --> 00:01:51,860 That means they can store number related values. 19 00:01:51,950 --> 00:02:02,970 They can also store string or text related values before creating variables is good to know. 20 00:02:03,160 --> 00:02:12,690 Some common convention when you are naming your variables variable names are case sensitive so you call 21 00:02:12,700 --> 00:02:15,620 Be careful where you give your variable names. 22 00:02:15,640 --> 00:02:23,150 For example if you name a variable H and then try to reference it using capital letter A. 23 00:02:23,340 --> 00:02:29,210 A tool not respond because they are treated as two different things. 24 00:02:29,320 --> 00:02:36,610 So make sure when you're creating variables you reference them using the exact name and case that you 25 00:02:36,610 --> 00:02:46,150 have created them in names in variables can be letters that can be alphanumeric so they can be letters 26 00:02:46,270 --> 00:02:47,940 and contain numbers. 27 00:02:47,980 --> 00:02:58,870 They can also contain signs like a dollar sign or the underscore variable names can not start with a 28 00:02:58,870 --> 00:02:59,810 number. 29 00:02:59,890 --> 00:03:05,830 You can embed a number in your variable name but you cannot start it with a number. 30 00:03:05,830 --> 00:03:07,090 For example you can call. 31 00:03:07,090 --> 00:03:11,130 You can call your variable 2 4 7 learning. 32 00:03:11,620 --> 00:03:16,570 You can start a variable with lowercase word. 33 00:03:16,570 --> 00:03:24,070 If you have a variable that has two words you can start it with the first letter being lowercase and 34 00:03:24,070 --> 00:03:29,190 then you can add the additional letters with an underscore. 35 00:03:29,320 --> 00:03:33,130 Doing it this way makes it a snake case. 36 00:03:33,130 --> 00:03:40,530 So when you have two words separated by an underscore for a variable name is called a snake case. 37 00:03:40,660 --> 00:03:45,100 You can also represented in camel case camel case. 38 00:03:45,100 --> 00:03:51,310 Basically means the first word is lowercase and the second word becomes uppercase. 39 00:03:51,320 --> 00:03:58,270 They call it camel case because it's got it looks like the hump of a camel. 40 00:03:58,270 --> 00:04:06,790 Also when you name your variables try to give your variable descriptive names that indicates what type 41 00:04:06,790 --> 00:04:11,470 of data or things that the variables are actually stored. 42 00:04:11,470 --> 00:04:19,300 For example if you are creating a variable regarding the score that in game stores you can call a game 43 00:04:19,810 --> 00:04:29,590 on the score score that is a good descriptive name for the type of information that that variable stores. 44 00:04:29,590 --> 00:04:37,350 Also when you are creating variables it is very important to know that you can not use the python reserve. 45 00:04:37,410 --> 00:04:46,420 Keywords reserve key words these are words that the actual Python programming language uses for different 46 00:04:46,420 --> 00:04:49,870 things so you cannot use them. 47 00:04:49,930 --> 00:04:55,280 So this is a table showing you the key words in the pie. 48 00:04:55,280 --> 00:04:56,660 Some programming language. 49 00:04:56,680 --> 00:05:02,650 These are words that you cannot use as variable names. 50 00:05:04,170 --> 00:05:09,120 So that's it for this video on the introduction to variables. 51 00:05:09,120 --> 00:05:11,100 Thanks for watching and bye for now.