The most straightforward way seems to use an external iterator to keep track. Note that this answer considers that you're looping on same sized lists. examplea = [10, 12, 14, 16, 18] b = [10, 8, 6, 4, 2] for i in range(len(a)):    print(a[i] + b[i])OutputThis will give the output −20 20 20 20 20ExampleYou can also use the zip method that stops when the shorter of a or b stops.a = [10, 12, 14, 16, 18] b = [10, 8, 6] for (A, B) in zip(a, b):    print(A + B)OutputThis will give the output −20 20 20

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

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

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

For expressions like − a == b first the python interpreter looks up the __eq__() method on the object a. If it finds that, then executes that with b as argument, ie, a.__eq__(b). If this method returns a NotImplemented, then it tries doind just the reverse, ie, it tries to call, b.__eq__(a)

The python operator performs very badly in a list, O(n), because it traverses the whole list. You can use something like a set or a dict(hashed data structures that have very fast lookups) to get the same result in ~O(1) time!But this also depends on the type of data structure you're looking at. This is because while lookups in sets/dicts are fast, insertion may take more time than list. So this speedup really depends on the type.

If you want to convert a statement like −if :    to a single line, You can use the single line if syntax to do so −if : Another way to do this is leveraging the short-circuiting and operator like − and If is false, then short-circuiting will kick in and the right-hand side won't be evaluated. If is true, then the right-hand side will be evaluated and will be evaluated.