The keywords are some predefined and reserved words in python that have special meaning. Keywords are used to define the syntax of the coding. The keyword cannot be used as an identifier, function, and variable name. All the keywords in python are written in lower case expect True and False. There are 33 keywords in Python 3.7 let’s go through all of them one by one.
Total Python keywords
| No. | Keywords | Description |
|---|---|---|
| 1 | and | This is a logical operator it returns true if both the operands are true else return false. |
| 2 | Or | This is also a logical operator it returns true if anyone operand is true else return false. |
| 3 | not | This is again a logical operator it returns True if the operand is false else return false. |
| 4 | if | This is used to make a conditional statement. |
| 5 | elif | Elif is a condition statement used with if statement the elif statement is executed if the previous conditions were not true |
| 6 | else | Else is used with if and elif conditional statement the else block is executed if the given condition is not true. |
| 7 | for | This is created for a loop. |
| 8 | while | This keyword is used to create a while loop. |
| 9 | break | This is used to terminate the loop. |
| 10 | as | This is used to create an alternative. |
| 11 | def | It helps us to define functions. |
| 12 | lambda | It used to define the anonymous function. |
| 13 | pass | This is a null statement that means it will do nothing. |
| 14 | return | It will return a value and exit the function. |
| 15 | True | This is a boolean value. |
| 16 | False | This is also a boolean value. |
| 17 | try | It makes a try-except statement. |
| 18 | with | The with keyword is used to simplify exception handling. |
| 19 | assert | This function is used for debugging purposes. Usually used to check the correctness of code |
| 20 | class | It helps us to define a class. |
| 21 | continue | It continues to the next iteration of a loop |
| 22 | del | It deletes a reference to an object. |
| 23 | except | Used with exceptions, what to do when an exception occurs |
| 24 | finally | Finally is use with exceptions, a block of code that will be executed no matter if there is an exception or not. |
| 25 | from | The form is used to import specific parts of any module. |
| 26 | global | This declares a global variable. |
| 27 | import | This is used to import a module. |
| 28 | in | It’s used to check if a value is present in a list, tuple, etc, or not. |
| 29 | is | This is used to check if the two variables are equal or not. |
| 30 | None | This is a special constant used to denote a null value or avoid. It’s important to remember, 0, any empty container(e.g empty list) do not compute to None |
| 31 | nonlocal | It’s declared a non-local variable. |
| 32 | raise | This raises an exception |
| 33 | yield | It’s ends a function and returns a generator. |
Identifiers: The identifier is a name used to identify a variable, function, class, module, etc. The identifier is a combination of character digits and underscore. The identifier should start with a character or Underscore then use digit. The characters are A-Z or a-z,a UnderScore ( _ ) and digit (0-9). we should not use special characters ( #, @, $, %, ! ) in identifiers.
Examples of valid identifiers:
- var1
- _var1
- _1_var
- var_1
Examples of invalid identifiers
- !var1
- 1var
- 1_var
- var#1
Example 1: Example of and, or, not, True, False keywords.
Python
print("example of True, False, and, or not keywords")# compare two operands using and operatorprint(True and True)# compare two operands using or operatorprint(True or False)# use of not operatorprint(not False) |
Output:
example of True, False, and, or not keywords True True True
Example 2: Example of a break, continue.
Python
# execute for loopfor i in range(1, 11): # print the value of i print(i) # check the value of i is less then 5 # if i lessthen 5 then continue loop if i < 5: continue # if i greather then 5 then break loop else: break |
Output:
1 2 3 4 5
Example 3: example of for, in, if, elif and else keyword.
Python
# run for loopfor t in range(1, 5): # print one of t ==1 if t == 1: print('One') # print two if t ==2 elif t == 2: print('Two') else: print('else block execute') |
Output:
One Two else block execute else block execute
Example 4: Example of def, if and else keywords.
Python
# define GFG() function using def keyworddef GFG(): i=20 # check i is odd or not # using if and else keyword if(i % 2 == 0): print("given number is even") else: print("given number is odd") # call GFG() function GFG() |
Output:
given number is even
Example 5: example try, except, raise.
Python
def fun(num): try: r = 1/num except: print('Exception raies') return return rprint(fun(10))print(fun(0)) |
Output:
0.1 Exception raies None
Example 6: Example of a lambda keyword.
Python
# define a anonymous using lambda keyword# this labda function increment the value of ba = lambda b: b+1# run a for loop for i in range(1, 6): print(a(i)) |
Output:
2 3 4 5 6
Example 7: use of return keyword.
Python
# define a functiondef fun(): # declare a variable a = 5 # return the value of a return a# call fun method and store# it's return value in a variable t = fun()# print the value of tprint(t) |
Output:
5
Example 8: use of a del keyword.
Python
# create a listl = ['a', 'b', 'c', 'd', 'e']# print list before using del keywordprint(l)del l[2]# print list after using del keywordprint(l) |
Output:
['a', 'b', 'c', 'd', 'e'] ['a', 'b', 'd', 'e']
Example 9: use of global keyword.
Python
# declare a variablegvar = 10# create a functiondef fun1(): # print the value of gvar print(gvar)# declare fun2()def fun2(): # declare global value gvar global gvar gvar = 100# call fun1()fun1()# call fun2()fun2() |
Output:
10
Example 10: example of yield keyword.
Python
def Generator(): for i in range(6): yield i+1t = Generator()for i in t: print(i) |
Output:
1 2 3 4 5 6
Example 10: example of assert keyword.
Python3
def sumOfMoney(money): assert len(money) != 0,"List is empty." return sum(money)money = []print("sum of money:",sumOfMoney(money)) |
Output:
AssertionError: List is empty.
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