1 00:00:00,510 --> 00:00:02,850 Welcome to the section and conditional statements. 2 00:00:04,380 --> 00:00:10,110 Conditional statements form a very important part of any programming language, and a Python programming 3 00:00:10,110 --> 00:00:13,500 language is no exception to this. 4 00:00:13,920 --> 00:00:15,900 Let's see how conditional statements work. 5 00:00:16,590 --> 00:00:18,090 Say you have a condition. 6 00:00:18,630 --> 00:00:22,770 Now, if this condition is verified, we can take an action. 7 00:00:22,770 --> 00:00:23,490 Say E. 8 00:00:24,240 --> 00:00:27,120 If this condition is not verified, you can take another action. 9 00:00:27,120 --> 00:00:31,110 B Suppose we have several conditions that is. 10 00:00:31,110 --> 00:00:32,490 N Different conditions. 11 00:00:33,000 --> 00:00:40,020 If the first condition, condition one is verified and all the other conditions as Condition I where 12 00:00:40,020 --> 00:00:44,580 I is different from one that is condition to right up to condition and unverified. 13 00:00:44,850 --> 00:00:53,580 Then we can take an action to e one else if this condition two is verified and condition one condition 14 00:00:53,580 --> 00:01:00,180 three of the condition and unverified, we can take an action A2 We're going to repeat this right up 15 00:01:00,180 --> 00:01:06,810 to condition n if condition and is verified on condition one right up to condition and minus one unverified, 16 00:01:06,840 --> 00:01:07,740 you can take an action. 17 00:01:07,750 --> 00:01:13,140 N Now if none of those conditions are verified, we can take an action and plus one. 18 00:01:14,400 --> 00:01:16,350 Let's get a more practical example. 19 00:01:16,950 --> 00:01:24,930 Suppose we want to write a computer program which when you input the fact that your do sports is going 20 00:01:24,930 --> 00:01:26,640 to tell you whether you are healthy or not. 21 00:01:27,420 --> 00:01:29,760 We could simply use condition statements. 22 00:01:30,450 --> 00:01:36,750 We have you that if we have spots that is if you are parts of then. 23 00:01:37,830 --> 00:01:39,690 Wish I'd been out healthy. 24 00:01:40,020 --> 00:01:43,980 And if you're not, then we print out unhealthy now. 25 00:01:44,430 --> 00:01:50,580 We have another example where we have this for sports, football, basketball, volleyball and tennis. 26 00:01:51,030 --> 00:01:58,680 Now we want to bring all the action you make whenever you are playing any of those parts. 27 00:01:59,040 --> 00:02:06,960 So if football is very that is if you are a footballer, then you kick before the goal is made else. 28 00:02:06,990 --> 00:02:09,330 If you're a basketball player, you make it true. 29 00:02:10,380 --> 00:02:13,170 If you're a volleyball, you make a hit. 30 00:02:13,680 --> 00:02:15,960 If you are a tennis player, you make a strike. 31 00:02:16,440 --> 00:02:20,460 And if you are none of this, we could see the action is unknown. 32 00:02:21,180 --> 00:02:22,320 So let's go straight away. 33 00:02:22,320 --> 00:02:25,380 It's look at us index of conditional statements and patent. 34 00:02:26,490 --> 00:02:36,690 So yeah, we have a variable sports so we would say sports true now and the session and valuable times. 35 00:02:36,690 --> 00:02:44,220 What didn't make mention of booleans now actually booleans are some sort of variables which take two 36 00:02:44,220 --> 00:02:46,530 values that is true or false. 37 00:02:46,770 --> 00:02:55,680 So booleans can be this true all false all likes in numbers which take values like so and int which 38 00:02:55,680 --> 00:02:58,260 takes values from negative say infinity. 39 00:02:59,880 --> 00:03:00,240 To. 40 00:03:01,230 --> 00:03:04,880 Positive infinity, which are all whole numbers. 41 00:03:07,290 --> 00:03:13,680 We took in an example with Booleans, we just have this two values, so we either have true or false. 42 00:03:13,950 --> 00:03:19,140 Notice that whenever we print out all, whenever we type out as true, it automatically turns green. 43 00:03:19,140 --> 00:03:21,470 And that's because this is a python keyword. 44 00:03:22,110 --> 00:03:25,680 So let's see how to use this in this example. 45 00:03:25,860 --> 00:03:26,760 So we have sports. 46 00:03:26,760 --> 00:03:27,210 True? 47 00:03:27,660 --> 00:03:31,560 I could say that if sports equals true. 48 00:03:35,400 --> 00:03:37,230 We have Prince. 49 00:03:39,750 --> 00:03:40,380 Healthy. 50 00:03:45,170 --> 00:03:52,510 Now we're receiving this error because we haven't used the right operator now for this F statement. 51 00:03:52,520 --> 00:03:55,460 We have to use the right operator for this to work out well. 52 00:03:56,600 --> 00:04:01,880 Instead of the equals, we actually have the double equals sign. 53 00:04:02,030 --> 00:04:07,070 So if we replace this with this w cosine, we shall see how this works out. 54 00:04:07,610 --> 00:04:09,470 So that works out now perfectly. 55 00:04:10,640 --> 00:04:15,110 It's important to note the syntax of the F statement we actually have. 56 00:04:15,560 --> 00:04:24,890 If we have a condition we have this column and then present enter would take us to the next line. 57 00:04:25,940 --> 00:04:31,100 Now let's look at another way of presenting this is that I've put in spots to be equals. 58 00:04:31,100 --> 00:04:31,400 True. 59 00:04:31,430 --> 00:04:32,720 What would you say if supports? 60 00:04:33,020 --> 00:04:38,990 Now if you say f sports, you are doing the same as seen if sports equals true. 61 00:04:39,800 --> 00:04:44,840 Now, if we change this true to false, we'll see that this is not going to be printed. 62 00:04:45,200 --> 00:04:48,080 So doing this we have not in print it out. 63 00:04:48,920 --> 00:04:51,050 Now, if we have this, we could say else. 64 00:04:51,320 --> 00:05:00,200 So for this, where we had if verified and now if not verify it, that is else we're going to have print, 65 00:05:01,820 --> 00:05:02,780 not healthy. 66 00:05:03,860 --> 00:05:04,820 Not healthy. 67 00:05:05,450 --> 00:05:11,300 And then we go see that we have printed out not healthy because sports is false. 68 00:05:11,300 --> 00:05:15,140 And so when it gets here, this condition is not verified. 69 00:05:15,380 --> 00:05:18,770 And if this condition is not verified, we think else. 70 00:05:19,010 --> 00:05:21,680 What else is actually the opposite of this? 71 00:05:22,100 --> 00:05:26,900 Now, the opposite of this being verified is this being not verified? 72 00:05:27,320 --> 00:05:37,550 So we could replace this else with an Aleph would have live sports equals false and we should have the 73 00:05:37,550 --> 00:05:39,440 same output. 74 00:05:40,370 --> 00:05:42,740 So this is the same as just do it else. 75 00:05:43,940 --> 00:05:44,540 So that's it. 76 00:05:45,110 --> 00:05:46,700 Now let's take this next example. 77 00:05:47,980 --> 00:05:48,610 We have. 78 00:05:51,320 --> 00:05:51,740 See. 79 00:05:53,480 --> 00:05:53,840 Part. 80 00:05:56,480 --> 00:06:03,200 Equals a list made up of the different spots a person actually practices. 81 00:06:03,230 --> 00:06:04,550 So we have this football. 82 00:06:05,030 --> 00:06:07,070 We have basketball. 83 00:06:07,730 --> 00:06:09,230 We have volleyball. 84 00:06:11,940 --> 00:06:13,860 And finally, we have Dennis. 85 00:06:16,060 --> 00:06:16,240 Now. 86 00:06:16,240 --> 00:06:16,840 We should see. 87 00:06:16,870 --> 00:06:19,570 If so, we could put this sparks. 88 00:06:20,860 --> 00:06:21,310 If. 89 00:06:22,850 --> 00:06:23,570 Football. 90 00:06:26,290 --> 00:06:27,640 In sports. 91 00:06:29,590 --> 00:06:30,520 What's the print? 92 00:06:32,370 --> 00:06:36,060 This person plays football. 93 00:06:38,510 --> 00:06:39,140 I leave? 94 00:06:41,160 --> 00:06:44,700 I was always advisable to put this in brackets so we could do this. 95 00:06:46,590 --> 00:06:47,410 And we have here. 96 00:06:47,970 --> 00:06:48,780 So leave. 97 00:06:50,090 --> 00:06:50,960 Basketball. 98 00:06:57,430 --> 00:06:58,270 In sports. 99 00:07:00,700 --> 00:07:01,210 Prince. 100 00:07:04,190 --> 00:07:07,310 This person plays basketball. 101 00:07:12,390 --> 00:07:12,960 A live. 102 00:07:15,550 --> 00:07:19,200 Basketball and sports. 103 00:07:22,490 --> 00:07:23,000 Prince. 104 00:07:29,720 --> 00:07:34,430 This person plays volleyball. 105 00:07:36,350 --> 00:07:37,400 Finally leave. 106 00:07:39,910 --> 00:07:40,540 Dennis. 107 00:07:44,680 --> 00:07:48,070 In sports we have. 108 00:07:51,860 --> 00:07:54,680 This person plays tennis. 109 00:07:55,700 --> 00:08:02,300 Now we have an area that's changed to volleyball and that's it. 110 00:08:02,990 --> 00:08:06,380 So let's run this and we have this person plays football. 111 00:08:06,890 --> 00:08:12,200 Now, this person actually has four different sports he or she practices. 112 00:08:12,710 --> 00:08:17,690 But in this case, or using this method, we actually print out football only. 113 00:08:17,870 --> 00:08:22,070 And that's because once we get into this first condition, we print out what we have first. 114 00:08:22,460 --> 00:08:29,360 And if this condition is verified, we print this and all this other conditions, Aaron's going to be 115 00:08:29,660 --> 00:08:30,420 looked again. 116 00:08:31,160 --> 00:08:34,400 So what the program does, it becomes and test this. 117 00:08:34,400 --> 00:08:41,900 If this is verified, it does this and all of this, other conditions are looked at. 118 00:08:42,350 --> 00:08:48,830 So to solve this problem where we may have situations like this where someone may have four different 119 00:08:48,830 --> 00:08:51,710 sports or could change the way we look at this. 120 00:08:52,310 --> 00:08:56,930 So let's take this cup of this right here. 121 00:08:58,010 --> 00:08:59,510 Now, I see if. 122 00:09:01,290 --> 00:09:01,980 Football. 123 00:09:03,810 --> 00:09:07,950 We're going to spin this so we could have print. 124 00:09:10,470 --> 00:09:11,670 We could actually copy this. 125 00:09:16,540 --> 00:09:17,350 Carpet it is out. 126 00:09:17,560 --> 00:09:25,090 We have brand is now instead of going into the next condition that's shifting to the next line, we 127 00:09:25,090 --> 00:09:29,860 could actually dess next condition in this F statement. 128 00:09:30,070 --> 00:09:32,710 And that is because if this is verified, we could have the next. 129 00:09:33,550 --> 00:09:34,240 Now we have. 130 00:09:34,900 --> 00:09:39,190 If so, here we have if football and sports. 131 00:09:42,160 --> 00:09:43,570 If basketball. 132 00:09:46,660 --> 00:09:47,500 In sports. 133 00:09:49,720 --> 00:09:50,200 Print out. 134 00:09:52,480 --> 00:09:55,740 We could use it that for us to move safely. 135 00:09:55,950 --> 00:09:57,650 What use in space lives when you're. 136 00:09:57,650 --> 00:09:57,970 Yeah. 137 00:09:58,120 --> 00:09:59,200 Avoid doing this. 138 00:10:00,490 --> 00:10:04,030 Instead use simply the tap to get to this point. 139 00:10:04,540 --> 00:10:07,510 And once we have this, we can print this pleasant place basketball. 140 00:10:10,950 --> 00:10:15,830 But on another point may arise where you are in playing football, but you're playing basketball. 141 00:10:15,840 --> 00:10:17,430 So suppose we have something like this. 142 00:10:17,970 --> 00:10:22,440 So in this case, if football in sports is not going to be verified, so we're not going to get into 143 00:10:22,440 --> 00:10:28,320 this now we have to make a way that if we have another condition, you're going to have another condition 144 00:10:28,650 --> 00:10:32,210 where if you're not playing football, we can get into this impasse. 145 00:10:32,220 --> 00:10:35,370 If you're playing basketball now, let's make this problem a bit simpler. 146 00:10:35,880 --> 00:10:36,900 We don't have this. 147 00:10:38,700 --> 00:10:39,480 In fact, we have. 148 00:10:44,100 --> 00:10:45,600 Just football and basketball. 149 00:10:47,700 --> 00:10:49,050 So, yeah, we have the owls. 150 00:10:51,780 --> 00:10:52,260 Prince. 151 00:10:54,280 --> 00:10:56,440 This person, all right? 152 00:10:56,440 --> 00:10:57,880 I don't even print anything, so. 153 00:10:57,880 --> 00:11:06,100 Yeah, we just test if basketball in sports print. 154 00:11:08,230 --> 00:11:11,980 This person plays basketball. 155 00:11:13,810 --> 00:11:14,500 So there we go. 156 00:11:15,310 --> 00:11:16,240 And we run this. 157 00:11:16,390 --> 00:11:19,150 We have this person plays football and pleasant basketball. 158 00:11:19,570 --> 00:11:21,070 So let's take it with basketball. 159 00:11:21,820 --> 00:11:23,500 We have this person plays football. 160 00:11:24,980 --> 00:11:26,620 Let's take a football. 161 00:11:29,520 --> 00:11:31,590 You have this pleasant place, basketball. 162 00:11:33,210 --> 00:11:39,480 But the issue is, if we increase this number of sports, we could have it becomes very difficult to 163 00:11:39,480 --> 00:11:40,950 work with it manually like this. 164 00:11:41,270 --> 00:11:42,630 Well, I would say volleyball. 165 00:11:44,340 --> 00:11:53,340 Volleyball would have to add this if and in this if we have to do an L statement again and then print 166 00:11:53,340 --> 00:11:58,800 out for the volleyball and come here again and print for volleyball and so on and so forth. 167 00:11:58,800 --> 00:12:03,840 So as we increase the number of possibilities for the sports, it becomes very complicated at the court. 168 00:12:04,170 --> 00:12:09,470 And that's where Lupe's come in, and that's what we shall see in the next section with Lopez. 169 00:12:09,480 --> 00:12:12,390 We shall see how to solve this problem very easily. 170 00:12:12,900 --> 00:12:16,050 So let's get back over there with this two for now. 171 00:12:18,880 --> 00:12:21,850 Let's remove this reload. 172 00:12:22,150 --> 00:12:23,110 Everything works fine. 173 00:12:25,390 --> 00:12:27,220 Now let's work with some numbers. 174 00:12:27,460 --> 00:12:29,430 So we have this number equals five. 175 00:12:29,440 --> 00:12:31,270 We have B equals seven. 176 00:12:31,660 --> 00:12:37,360 Good test if E equals five prints. 177 00:12:40,080 --> 00:12:40,590 Stillman. 178 00:12:40,590 --> 00:12:41,160 Correct. 179 00:12:41,700 --> 00:12:42,690 Would you say correct. 180 00:12:45,400 --> 00:12:53,540 We could also have if E is less than B prince, correct? 181 00:12:56,890 --> 00:13:02,590 It could also have if is great and b prince. 182 00:13:07,400 --> 00:13:08,330 Not correct. 183 00:13:10,920 --> 00:13:12,600 If E. 184 00:13:14,590 --> 00:13:19,720 You have a model of B, for example, equals one. 185 00:13:21,730 --> 00:13:22,230 Prince. 186 00:13:24,070 --> 00:13:24,940 Not correct. 187 00:13:28,110 --> 00:13:29,310 And we can load the cell. 188 00:13:29,700 --> 00:13:36,780 Loading the cell, we have this first to correct us because equals five and then here we have 11 B, 189 00:13:36,780 --> 00:13:37,590 which is correct. 190 00:13:37,890 --> 00:13:45,530 Now it good and which is not true because is actually less than b we have a modulo B which in this case 191 00:13:45,530 --> 00:13:48,450 is actually equals five and is not equals one. 192 00:13:48,450 --> 00:13:49,680 So bring out not correct. 193 00:13:49,920 --> 00:13:58,740 And since this is now equals one, we have not printed its out so we could test this prin e one of the 194 00:13:58,750 --> 00:14:01,380 b is clearly five which is now equals one. 195 00:14:01,380 --> 00:14:03,140 So we don't get into this now. 196 00:14:03,240 --> 00:14:03,660 What is that? 197 00:14:03,660 --> 00:14:05,820 Would this are a way of writing? 198 00:14:06,210 --> 00:14:13,200 We get into each and every condition and that is because once we have those, if the program looks for 199 00:14:13,200 --> 00:14:13,680 the next. 200 00:14:14,310 --> 00:14:24,390 So if there is C an L statement here, user prints, whatever, no matter what you have here, is never 201 00:14:24,390 --> 00:14:26,670 going to be printed if this condition is verified. 202 00:14:27,030 --> 00:14:34,020 So like this, for example, this whatever is not printed, but when you have this if statement or when 203 00:14:34,020 --> 00:14:39,690 you have this if statement followed by another, if did mean this other estimate is going to be looked 204 00:14:39,690 --> 00:14:40,020 at. 205 00:14:40,470 --> 00:14:48,060 So what a program does is it looks at if it looks at whether it is elseif ELIF or else and if that is 206 00:14:48,060 --> 00:14:49,770 not there, we just move on. 207 00:14:49,770 --> 00:14:50,700 So we'll go to this. 208 00:14:50,700 --> 00:14:57,060 If two must get into this, if that is different from C in this case where we had Elif would leave. 209 00:14:57,240 --> 00:14:59,520 If this is verify, we don't get into this again. 210 00:14:59,970 --> 00:15:06,600 But what if even if this is verified or if it's verified, this other condition is going to be distant. 211 00:15:07,470 --> 00:15:11,640 Now let's look at the lesson I equals condition. 212 00:15:11,640 --> 00:15:15,630 So here we have the lesson equals operation. 213 00:15:15,900 --> 00:15:16,740 So we have this. 214 00:15:17,700 --> 00:15:19,680 Now let's get what we have here. 215 00:15:19,860 --> 00:15:21,360 So we have this correct. 216 00:15:21,780 --> 00:15:25,890 This lesson equals B this is actually correct because this is less than so. 217 00:15:25,890 --> 00:15:30,660 One of the conditions of a verified and this is not correct, this key is not correct. 218 00:15:31,410 --> 00:15:33,300 So now let's suppose this two are the same. 219 00:15:33,300 --> 00:15:39,780 So let's put this two five we have this other one is printed out and that's simply because let's take 220 00:15:39,780 --> 00:15:46,020 this out and that's simply because with a less than equals, we are saying in this case, if is less 221 00:15:46,020 --> 00:15:46,920 on our equals. 222 00:15:47,220 --> 00:15:47,640 Correct. 223 00:15:48,180 --> 00:15:49,650 And this gives this actually equal. 224 00:15:49,650 --> 00:15:51,900 So we have no problem with that. 225 00:15:52,170 --> 00:15:54,330 In this case, it is greater than all equals. 226 00:15:54,540 --> 00:15:55,570 We can do this. 227 00:15:55,570 --> 00:16:03,960 So this is the same as saying if E is greater than B or E is equals B. 228 00:16:03,960 --> 00:16:07,380 So this is the same statement was common this. 229 00:16:08,890 --> 00:16:09,580 So there we go. 230 00:16:10,060 --> 00:16:11,220 Now, we could take this off 231 00:16:14,380 --> 00:16:15,640 and we're on this. 232 00:16:15,820 --> 00:16:17,440 Still have the same output. 233 00:16:18,070 --> 00:16:23,320 We could also have if equals five, replace with if is five. 234 00:16:23,440 --> 00:16:25,990 So we're going to have this and we'll see that it's actually printed out. 235 00:16:26,440 --> 00:16:27,460 Now, let's take this off. 236 00:16:28,570 --> 00:16:30,130 Yeah, we have if is five. 237 00:16:30,550 --> 00:16:31,120 Correct. 238 00:16:31,600 --> 00:16:33,940 So this is another way of writing. 239 00:16:33,940 --> 00:16:34,930 This equals. 240 00:16:35,470 --> 00:16:36,930 So we just does this direct. 241 00:16:36,970 --> 00:16:38,320 Now, if it's not five. 242 00:16:40,130 --> 00:16:41,210 See they're not in the screen yet. 243 00:16:41,210 --> 00:16:45,620 So we could have else prints not in a sprint printed. 244 00:16:47,430 --> 00:16:48,150 So there we go. 245 00:16:49,320 --> 00:16:51,960 Now that we've seen this, we shall go to the lips.