1
00:00:00,000 --> 00:00:04,099
Friends, as of now we completed three types of operators,

2
00:00:04,200 --> 00:00:08,900
right? They are arithmetic, assignment, and comparison operators.

3
00:00:09,000 --> 00:00:12,000
Now, we are going to discuss two more operators.

4
00:00:12,000 --> 00:00:15,000
They are identity and membership operators.

5
00:00:16,000 --> 00:00:18,800
See why we are using, how we can use them in our

6
00:00:18,800 --> 00:00:20,700
real-time, right. First

7
00:00:20,700 --> 00:00:26,100
let me go with the identity operators. See identity operators

8
00:00:26,100 --> 00:00:29,600
are used to find the type of your object.

9
00:00:29,600 --> 00:00:31,500
[no audio]

10
00:00:31,500 --> 00:00:32,799
It may be class.

11
00:00:33,500 --> 00:00:35,300
What is the type of your object?

12
00:00:35,700 --> 00:00:38,400
It may be class or type,

13
00:00:38,400 --> 00:00:39,400
maybe object.

14
00:00:39,500 --> 00:00:43,600
I mean for time being let me give you a very simple example.

15
00:00:43,600 --> 00:00:45,600
[no audio]

16
00:00:45,600 --> 00:00:47,200
I'm going to open my terminal.

17
00:00:47,200 --> 00:00:54,700
[no audio]

18
00:00:54,700 --> 00:00:56,300
Okay, fine. Just observe here.

19
00:00:56,400 --> 00:01:00,000
We have some 'x' value, or let me define some new value for

20
00:01:00,000 --> 00:01:05,200
'x', and 'y="hi"'. Then what is the type of your

21
00:01:05,200 --> 00:01:09,900
'x'? Integer. Then what is the type of your 'y'?

22
00:01:09,900 --> 00:01:12,000
[no audio]

23
00:01:12,000 --> 00:01:17,200
So this is type. 'type()', your variable suppose 'x' and 'y'. Now,

24
00:01:17,200 --> 00:01:20,500
let's say I am going to define one more variable called 'y',

25
00:01:20,500 --> 00:01:23,900
'y=7', then what is the type of your 'y'?

26
00:01:25,200 --> 00:01:35,100
Integer. Guys if I check 'x==y', no, 'False'. But 'x' and 'y' type is same.

27
00:01:35,400 --> 00:01:38,300
What is the type? Integer type. Now,

28
00:01:38,300 --> 00:01:44,200
I want to verify suppose for two variables whether the type

29
00:01:44,200 --> 00:01:45,600
is similar or not.

30
00:01:46,200 --> 00:01:55,700
I mean, let's say is 'type(x) is type(y)'. That means,

31
00:01:55,700 --> 00:01:57,500
are they equal? Yes, 'True'.

32
00:01:58,700 --> 00:02:05,800
But if I take 'type(x) is type()', let me define

33
00:02:05,800 --> 00:02:08,100
[no audio]

34
00:02:08,199 --> 00:02:13,100
'z=', some string. Now, you know 'type(z) is string. So 'x'

35
00:02:13,100 --> 00:02:15,200
is integer and 'z' is string.

36
00:02:15,500 --> 00:02:20,400
Now, what I am doing is I am going to compare 'type(x) is type(z)'.

37
00:02:20,700 --> 00:02:24,200
No. 'type(x) is not 'type(z)'.

38
00:02:24,200 --> 00:02:25,400
Yes, they are not equal.

39
00:02:25,400 --> 00:02:28,100
We know that, because we know what the value we stored in

40
00:02:28,100 --> 00:02:32,000
'x' and 'y', that's why 'type(x)' is integer and 'type(z)' is string,

41
00:02:32,000 --> 00:02:35,400
but we are saying that yes, they are not, they are not equal

42
00:02:35,400 --> 00:02:36,400
in type wise.

43
00:02:37,000 --> 00:02:42,700
Yes. So in identity operators we have two types of operators, they are

44
00:02:42,700 --> 00:02:48,100
'is' and 'is not'. So guys simply remember that identity operators

45
00:02:48,100 --> 00:02:53,300
are used to find the type of your variable suppose or type

46
00:02:53,300 --> 00:02:59,200
of your variable, right, or your object. Sometimes you know,

47
00:02:59,200 --> 00:03:02,900
you are going to get your type maybe class or some object.

48
00:03:04,400 --> 00:03:08,800
So for time being we know if you find the type of some variable

49
00:03:08,800 --> 00:03:12,300
you're going to get either integer or float or complex or

50
00:03:12,300 --> 00:03:15,100
string or byte, right?

51
00:03:15,100 --> 00:03:16,700
Well, going forward we will see

52
00:03:16,700 --> 00:03:20,100
whenever if we get some different types there

53
00:03:20,100 --> 00:03:23,000
again we can use this identity operators.

54
00:03:24,400 --> 00:03:28,700
Right. Fine. Then next one is membership operators.

55
00:03:29,700 --> 00:03:34,100
See membership operators are used to validate the membership

56
00:03:34,100 --> 00:03:35,100
of a value.

57
00:03:35,100 --> 00:03:37,300
[no audio]

58
00:03:37,300 --> 00:03:40,400
Anyway by seeing this you don't get much information, but

59
00:03:40,400 --> 00:03:43,800
I want to give one thing. First thing, very simple information

60
00:03:43,800 --> 00:03:49,800
guys. Observe this. I have a list of values called 4, 5, 6, 7

61
00:03:49,800 --> 00:03:53,000
[no audio]

62
00:03:53,000 --> 00:03:55,900
Right. '6 in x', Yes.

63
00:03:57,200 --> 00:04:01,100
'90 in x', no, right.

64
00:04:01,400 --> 00:04:04,300
Let us assume that in your real time you are doing some script.

65
00:04:04,800 --> 00:04:07,500
The purpose of your script is, right,

66
00:04:07,900 --> 00:04:09,900
first of all you have some valid,

67
00:04:10,100 --> 00:04:13,300
let us assume valid Java versions.

68
00:04:13,400 --> 00:04:16,600
Let's say 1.6 and 1.7,

69
00:04:17,800 --> 00:04:21,300
or let me take 1.9 as well, 1.8,

70
00:04:21,300 --> 00:04:23,700
[no audio]

71
00:04:23,700 --> 00:04:28,600
and then 1.9. Just assume that these only your valid Java

72
00:04:28,600 --> 00:04:30,700
versions. You should have only these Java

73
00:04:30,700 --> 00:04:32,500
versions on your environment.

74
00:04:34,800 --> 00:04:37,500
What happened? Something wrong.

75
00:04:37,500 --> 00:04:40,900
[no audio]

76
00:04:40,900 --> 00:04:44,700
1.6, yeah. I missed here quotation. Fine.

77
00:04:46,100 --> 00:04:49,600
Okay, first before writing your Python Script, right,

78
00:04:50,700 --> 00:04:55,600
first of all I am assuming that 1.6, 1.7, 1.8, and 1.9 are valid

79
00:04:55,600 --> 00:04:56,600
Java versions.

80
00:04:57,700 --> 00:05:01,600
Right. These are the valid versions but on my host what is

81
00:05:01,600 --> 00:05:04,300
the Java version I have I don't know, but through Python Script

82
00:05:04,300 --> 00:05:07,000
just assume that, because as of now you cannot write your

83
00:05:07,000 --> 00:05:10,800
script to find Java version from your local host. Just assumption.

84
00:05:11,500 --> 00:05:12,800
So, 'host_java',

85
00:05:12,800 --> 00:05:14,600
[no audio]

86
00:05:14,600 --> 00:05:18,000
I'm finding like this, something like that, but I'm not going

87
00:05:18,000 --> 00:05:21,800
to write. I am writing some logic, through that I got version as 1.5.

88
00:05:23,000 --> 00:05:25,800
Now what I have to do is, if your 'host_java',

89
00:05:25,800 --> 00:05:27,800
[no audio]

90
00:05:27,800 --> 00:05:32,700
if it is there in your valid then I can say, host consists of valid Java

91
00:05:32,700 --> 00:05:35,300
version. So 'host_java in valid_java'?

92
00:05:35,400 --> 00:05:36,500
No, 'False'.

93
00:05:36,500 --> 00:05:42,300
Now, I can say that, now I can say that, right, your host does

94
00:05:42,300 --> 00:05:45,000
not consist of a valid Java version.

95
00:05:45,500 --> 00:05:47,200
Let me write simple script for this.

96
00:05:47,200 --> 00:05:50,600
[no audio]

97
00:05:50,600 --> 00:05:53,100
Nothing is the there, membership. Something is there in a given

98
00:05:53,100 --> 00:05:55,700
group of values or not, that's it.

99
00:05:55,700 --> 00:05:59,800
[no audio]

100
00:05:59,800 --> 00:06:04,000
Very, very useful in your real time. Situation is same,

101
00:06:04,000 --> 00:06:07,600
I mean scenario where you can use your membership operators

102
00:06:08,300 --> 00:06:09,500
that scenario is same.

103
00:06:09,500 --> 00:06:11,400
[no audio]

104
00:06:11,400 --> 00:06:15,600
Let me copy. These are the 'valid_java' versions, and with some

105
00:06:15,600 --> 00:06:17,000
logic. As of now directly

106
00:06:17,000 --> 00:06:19,700
I am writing your 'host_java'.

107
00:06:19,700 --> 00:06:22,300
But what I will do is in your real time I will add some

108
00:06:22,300 --> 00:06:24,400
logic to get the 'host_java',

109
00:06:24,400 --> 00:06:25,600
whatever the version is there.

110
00:06:26,000 --> 00:06:29,700
Now, what I am doing is, 'if', as of now I don't know

111
00:06:30,000 --> 00:06:36,700
about your 'if' statement, just observe that. 'if host_java

112
00:06:36,700 --> 00:06:40,900
in valid_java', then I can say 'print("host consists of

113
00:06:40,900 --> 00:06:42,900
[no audio]

114
00:06:42,900 --> 00:06:46,500
valid Java version"), 'else:'

115
00:06:46,500 --> 00:06:51,200
[no audio]

116
00:06:51,200 --> 00:06:53,400
"host consists of", or "host deployed with",

117
00:06:53,400 --> 00:06:58,700
instead of "consist", you can use "host deployed with invalid

118
00:06:59,600 --> 00:07:00,800
Java version.

119
00:07:00,800 --> 00:07:06,300
[no audio]

120
00:07:06,300 --> 00:07:08,900
So assume that this is one script,

121
00:07:09,500 --> 00:07:13,900
okay, and I am going to run this script. Just see the output

122
00:07:13,900 --> 00:07:16,300
what you are getting. "Host deployed with invalid Java

123
00:07:16,300 --> 00:07:19,800
version". Now, let us assume that you are going to run this

124
00:07:19,800 --> 00:07:21,100
script on another server.

125
00:07:21,200 --> 00:07:25,300
There you have 1.7. Now if you observe what is the code you're getting?

126
00:07:25,400 --> 00:07:27,300
"host deployed with a valid Java version".

127
00:07:27,300 --> 00:07:30,600
That means some particular value, whether it is there in a

128
00:07:30,600 --> 00:07:32,400
given list of values or not,

129
00:07:33,500 --> 00:07:35,900
right, for that you're going to use membership operator.

130
00:07:36,800 --> 00:07:39,000
Not only that, just assumption, one more thing, because

131
00:07:39,100 --> 00:07:41,000
these membership operators are very, very important

132
00:07:41,000 --> 00:07:45,800
I am going to give one more example. That is, there are some

133
00:07:45,800 --> 00:07:51,200
'db_groups', or there are some predefined 'db_users' or

134
00:07:51,200 --> 00:07:52,900
'admin_user', something like that,

135
00:07:53,100 --> 00:07:54,400
okay, just assumption

136
00:07:54,900 --> 00:07:59,500
So some 'db_admin' user.

137
00:08:01,200 --> 00:08:02,700
Then let us assume that

138
00:08:02,700 --> 00:08:04,900
[no audio]

139
00:08:04,900 --> 00:08:06,600
'db_conf' user,

140
00:08:06,600 --> 00:08:15,000
[no audio]

141
00:08:15,000 --> 00:08:19,200
'db_installation' user, something like that, okay.

142
00:08:19,700 --> 00:08:23,600
Now I have some user, with that user

143
00:08:24,200 --> 00:08:25,900
I need to start my application.

144
00:08:26,200 --> 00:08:28,600
Just assume that. I mean I need to start my DB, just assume

145
00:08:28,600 --> 00:08:31,600
that the users which are there in this,

146
00:08:31,700 --> 00:08:34,900
let me take this as 'db_users', the users which are

147
00:08:34,900 --> 00:08:38,299
there in this, they only can start your db application.

148
00:08:38,200 --> 00:08:39,299
Just assume that.

149
00:08:40,000 --> 00:08:44,200
Right. So in my hand, I have some user, random user.

150
00:08:44,200 --> 00:08:47,100
I don't know whether that user is a valid DB user or not.

151
00:08:47,400 --> 00:08:49,200
Just I got some random user.

152
00:08:49,600 --> 00:08:56,000
Let's say 'db_admin'. See if this user is there in a given group 'db_users'

153
00:08:56,000 --> 00:09:01,200
then I can allow to, I mean you can allow that user to start

154
00:09:01,200 --> 00:09:02,300
your DB application.

155
00:09:02,400 --> 00:09:09,400
That's why what I am doing is, right, 'if' your DB, or let's

156
00:09:09,400 --> 00:09:17,200
say a 'random_user', right, 'if random_user in 'db_users', then

157
00:09:17,200 --> 00:09:18,800
I can say 'print'.

158
00:09:19,300 --> 00:09:21,000
"yes this user

159
00:09:21,000 --> 00:09:23,000
[no audio]

160
00:09:23,000 --> 00:09:27,700
is allowed to start db")'. That's it.

161
00:09:29,100 --> 00:09:32,000
'else: print("

162
00:09:32,000 --> 00:09:34,500
[no audio]

163
00:09:34,500 --> 00:09:36,900
this is, this user

164
00:09:36,900 --> 00:09:40,500
[no audio]

165
00:09:40,500 --> 00:09:45,800
is not a valid user, or authorized, is not a valid user

166
00:09:46,600 --> 00:09:50,300
to start db", right. First

167
00:09:50,400 --> 00:09:53,400
let me run this code and observe the output. Before that

168
00:09:53,400 --> 00:09:55,300
I am going to comment your previous code.

169
00:09:55,300 --> 00:09:58,600
[no audio]

170
00:09:58,600 --> 00:10:01,800
So guys, we will write a script to find out even this db_users,

171
00:10:01,800 --> 00:10:04,800
valid db_users on your particular host. Right.

172
00:10:05,700 --> 00:10:08,500
So everything we can write a script but initially, right,

173
00:10:08,900 --> 00:10:11,800
I cannot go and write some complicated script, and I don't

174
00:10:11,800 --> 00:10:14,000
want to confuse you that is why I am taking simply, directly the

175
00:10:14,000 --> 00:10:17,500
output. Okay, observe the output. First,

176
00:10:18,800 --> 00:10:22,100
if 'db_admin', yes, this user is allowed to start. Now,

177
00:10:22,100 --> 00:10:24,400
let us assume that there is some user you don't know, some

178
00:10:24,400 --> 00:10:30,200
'xyz' user, before going to start your DB by that 'xyz' user

179
00:10:30,200 --> 00:10:34,400
what I will do is, if that 'random_user' in my 'valid_db' users

180
00:10:34,400 --> 00:10:38,200
list then only I have to, otherwise I have to say, see the output,

181
00:10:38,200 --> 00:10:40,800
"This user is not a valid user to start db".

182
00:10:41,400 --> 00:10:45,600
So simply what you are doing, you are checking something is

183
00:10:45,600 --> 00:10:51,100
there in a given list or not. To check that we are using membership operators.

184
00:10:51,100 --> 00:10:53,800
[no audio]

185
00:10:53,800 --> 00:10:59,100
Right. So whatever the thing you have, right, if that thing is

186
00:10:59,100 --> 00:11:02,000
in the list of values, you will get output as 'True' whenever

187
00:11:02,000 --> 00:11:05,200
if you are going to compare, and, sorry, whenever you are going

188
00:11:05,200 --> 00:11:09,200
to use your membership operators, 'False'. And you have one more

189
00:11:09,200 --> 00:11:11,700
thing, 'not in',

190
00:11:11,700 --> 00:11:14,000
[no audio]

191
00:11:14,000 --> 00:11:16,800
whether given value is not there in a list.

192
00:11:16,800 --> 00:11:18,300
Yes, not in. 'True'.

193
00:11:18,800 --> 00:11:23,000
Right. So you have two types of membership operators,

194
00:11:23,000 --> 00:11:27,500
they are 'in' and 'not in'. Guys, maybe little bit confusion,

195
00:11:27,600 --> 00:11:30,900
but while writing scripts with your 'if' condition while going

196
00:11:30,900 --> 00:11:34,900
forward, you will get a clear clarity on these identity operators

197
00:11:34,900 --> 00:11:38,900
and membership operators. For time being just assume that some

198
00:11:38,900 --> 00:11:42,500
value you have to compare, you have to check whether it is

199
00:11:42,500 --> 00:11:45,600
there in the given list of values or not. To check that we

200
00:11:45,600 --> 00:11:49,200
are using membership operators. That's it. Okay.

201
00:11:49,200 --> 00:11:51,306
[no audio]