Python provides two ways to write inline if statements. These are:1. if condition: statement2. s1 if condition else s2Note that second type of if cannot be used without an else. Now you can use these inline in a print statement as well. For example,a = True if a: print("Hello")This will give the output:Helloa = False print("True" if a else "False")This will give the output:False

There are multiple ways in which you can use if else construct in the command line in python. For example, bash supports multiline statements, which you can use like:$ python -c ' > a = True > if a: > print("a is true") > 'This will give the output:a is trueIf you prefer to have the python statement in a single line, you can use the newline between the commands. For example,$ python -c $'a = Trueif a: print("a is true");'This will give the output:a is true

You can put comments anywhere in an if...elif...else statement, ie before each of these blocks or within each of these blocks. Note that you cannot put multiline comments before elif and else blocks though, as these comments are actually strings which imply a break in the whole construct. For example,# If check if True:    # Another Comment style    print("If block") # Else if statement elif False:    # Another Comment style    print("elif block") # Else else:    # Another Comment style    print("Else block")This will give the output:If block

You can do this directly if you are surrounding your multiline if statements conditions in a parenthesis. For example,if (cond1 == 'val1' and    cond2 == 'val2' and # Some comment    cond3 == 'val3' and # Some comment    cond4 == 'val4'):However, this is not possible if you try to do this without a parenthesis. For example, the following code will give an error:if cond1 == 'val1' and \    cond2 == 'val2' and \ # Some comment    cond3 == 'val3' and \ # Some comment    cond4 == 'val4':

Here are some of the most common python programming mistakes/gotchas that programmers commit:Scope name lookups: Python follows scoping rules in order of LEGB(Local, Enclosing, Global, Built-in). Since python has no strict type binding, programmers can reassociate an outer scope variable to another value that might be used in the outer scope later but is now replaced by some other value.Not differentiating between is and =: The is an operator in python checks if both objects refer to the same memory address. The == operator executes __eq__ function which might check for equality differently for different classes.Modifying a list while iterating ... Read More

Here are some of the most common python programming mistakes/gotchas that programmers commit −Scope name lookups − Python follows scoping rules in order of LEGB(Local, Enclosing, Global, Built-in). Since python has no strict type binding, programmers can reassociate an outer scope variable to another value that might be used in the outer scope later but is now replaced by some other value.Not differentiating between is and == − The is an operator in python checks if both objects refer to the same memory address. The == operator executes __eq__ function which might check for equality differently for different classes.Modifying a ... Read More

You can compare 2 variables in an if statement using the == operator. examplea = 10 b = 15 if a == b:    print("Equal") else:    print("Not equal")OutputThis will give the output −Not EqualYou can also use the is the operator. examplea = "Hello" b = a if a is b:    print("Equal") else:    print("Not equal")OutputThis will give the output −EqualNote that is will return True if two variables point to the same object, == if the objects referred to by the variables are equal.

There are many ways you can style multiple if conditions. You don't need to use 4 spaces on your second conditional line. So you can use something like &minusl;if (cond1 == 'val1' and cond2 == 'val2' and     cond3 == 'val3' and cond4 == 'val4'):# Actual codeYou can also start the conditions from the next line −if (    cond1 == 'val1' and cond2 == 'val2' and    cond3 == 'val3' and cond4 == 'val4' ):# Actual codeOr you can provide enough space between if and ( to accomodate the conditions in the same vertical column.if (cond1 == 'val1' ... Read More

Here are some of the steps that you can follow to optimize a nested if...elif...else.1. Ensure that the path that'll be taken most is near the top. This ensures that not multiple conditions are needed to be checked on the most executed path.2. Similarly, sort the paths by most use and put the conditions accordingly.3. Use short-circuiting to your advantage. If you have a statement like:if heavy operation() and light operation():Then consider changing it toif lightOperation() and heavy operation():This will ensure that heavy operation is not even executed if the light operation is false. Same can be done with or ... Read More

The ternary operator cannot be overloaded. Though you can wrap it up in a lambda/function and use it. For exampleresult = lambda x: 1 if x < 3 else 10 print(result(2)) print(result(1000))OutputThis will give the output −1 10