• Python Stop Program Execution
• Python Execution File

What is Loop?Loops can execute a block of code number of times until a certain condition is met. Their usage is fairly common in programming. Unlike other programming language that have For Loop, while loop, dowhile, etc.

What is For Loop?For loop is used to iterate over elements of a sequence. It is often used when you have a piece of code which you want to repeat 'n' number of time.What is While Loop?While Loop is used to repeat a block of code. Instead of running the code block once, It executes the code block multiple times until a certain condition is met.In this tutorial, we will learn.How to use 'While Loop'While loop does the exactly same thing what 'if statement' does, but instead of running the code block once, they jump back to the point where it began the code and repeats the whole process again.Syntaxwhile expressionStatementExample:##Example file for working with loops#def main:x=0#define a while loopwhile(x.

Code Line 5: Print the month How to use break statements in For LoopBreakpoint is a unique function in For Loop that allows you to break or terminate the execution of the for loopExample:def main:#use a for loop over a collection#Months = 'Jan','Feb','Mar','April','May','June'#for m in Months:#print m# use the break and continue statementsfor x in range (10,20):if (x 15): break#if (x% 2 0): continueprint(x)if name 'main':main In this example, we declared the numbers from 10-20, but we want that our for loop to terminate at number 15 and stop executing further. Python loopWorking Code for all exercisesCode for while loopdef main:x=0while (x.

for n in range ( 2, 10 ). For x in range ( 2, n ). If n% x 0. Print n, 'equals', x, '.' , n / x. # loop fell through without finding a factor. Print n, 'is a prime number'.

2 is a prime number 3 is a prime number 4 equals 2. 2 5 is a prime number 6 equals 2. 3 7 is a prime number 8 equals 2.

4 9 equals 3. 3(Yes, this is the correct code. Look closely: the else clause belongs tothe loop, not the statement.)When used with a loop, the else clause has more in common with theelse clause of a statement than it does that ofstatements: a statement’s else clause runswhen no exception occurs, and a loop’s else clause runs when no breakoccurs. For more on the statement and exceptions, see.The statement, also borrowed from C, continues with the nextiteration of the loop. def fib ( n ): # write Fibonacci series up to n. 'Print a Fibonacci series up to n.' While a # Now call the function we just defined.

Fib ( 2000 ) 0 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610 987 1597The keyword introduces a function definition. fib f = fib f ( 100 ) 0 1 1 2 3 5 8 13 21 34 55 89Coming from other languages, you might object that fib is not a function buta procedure since it doesn’t return a value. In fact, even functions without astatement do return a value, albeit a rather boring one. Thisvalue is called None (it’s a built-in name). Writing the value None isnormally suppressed by the interpreter if it would be the only value written.You can see it if you really want to using. def fib2 ( n ): # return Fibonacci series up to n. 'Return a list containing the Fibonacci series up to n.'

While a f100 = fib2 ( 100 ) # call it f100 # write the result 0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89This example, as usual, demonstrates some new Python features:.The statement returns with a value from a function.without an expression argument returns None. Falling offthe end of a function also returns None.The statement result.append(a) calls a method of the list objectresult. A method is a function that ‘belongs’ to an object and is namedobj.methodname, where obj is some object (this may be an expression),and methodname is the name of a method that is defined by the object’s type.Different types define different methods.

Methods of different types may havethe same name without causing ambiguity. (It is possible to define your ownobject types and methods, using classes, see )The method append shown in the example is defined for list objects; itadds a new element at the end of the list.

In this example it is equivalent toresult = result + a, but more efficient. Def askok ( prompt, retries = 4, complaint = 'Yes or no, please!' ): while True: ok = rawinput ( prompt ) if ok in ( 'y', 'ye', 'yes' ): return True if ok in ( 'n', 'no', 'nop', 'nope' ): return False retries = retries - 1 if retries. Parrot # required argument missing parrot ( voltage = 5.0, 'dead' ) # non-keyword argument after a keyword argument parrot ( 110, voltage = 220 ) # duplicate value for the same argument parrot ( actor = 'John Cleese' ) # unknown keyword argumentIn a function call, keyword arguments must follow positional arguments.All the keyword arguments passed must match one of the argumentsaccepted by the function (e.g. Actor is not a valid argument for theparrot function), and their order is not important.

Benjamin britten nocturnal after john dowland pdf. This also includesnon-optional arguments (e.g. Parrot(voltage=1000) is valid too).No argument may receive a value more than once.Here’s an example that fails due to this restriction. def function ( a ). function ( 0, a = 0 ) Traceback (most recent call last):File ', line 1, in TypeError: function got multiple values for keyword argument 'a'When a final formal parameter of the form.name is present, it receives adictionary (see ) containing all keyword arguments except forthose corresponding to a formal parameter.

This may be combined with a formalparameter of the form.name (described in the next subsection) whichreceives a tuple containing the positional arguments beyond the formal parameterlist. (.name must occur before.name.) For example, if we define afunction like this.

Python Stop Program Execution

Documentation StringsThere are emerging conventions about the content and formatting of documentationstrings.The first line should always be a short, concise summary of the object’spurpose. For brevity, it should not explicitly state the object’s name or type,since these are available by other means (except if the name happens to be averb describing a function’s operation). This line should begin with a capitalletter and end with a period.If there are more lines in the documentation string, the second line should beblank, visually separating the summary from the rest of the description. Thefollowing lines should be one or more paragraphs describing the object’s callingconventions, its side effects, etc.The Python parser does not strip indentation from multi-line string literals inPython, so tools that process documentation have to strip indentation ifdesired.

This is done using the following convention. The first non-blank lineafter the first line of the string determines the amount of indentation forthe entire documentation string. (We can’t use the first line since it isgenerally adjacent to the string’s opening quotes so its indentation is notapparent in the string literal.) Whitespace “equivalent” to this indentation isthen stripped from the start of all lines of the string. Lines that areindented less should not occur, but if they occur all their leading whitespaceshould be stripped. Equivalence of whitespace should be tested after expansionof tabs (to 8 spaces, normally).Here is an example of a multi-line docstring.

Python Execution File

Intermezzo: Coding StyleNow that you are about to write longer, more complex pieces of Python, it is agood time to talk about coding style. Most languages can be written (or moreconcise, formatted) in different styles; some are more readable than others.Making it easy for others to read your code is always a good idea, and adoptinga nice coding style helps tremendously for that.For Python, has emerged as the style guide that most projects adhere to;it promotes a very readable and eye-pleasing coding style. Every Pythondeveloper should read it at some point; here are the most important pointsextracted for you:.Use 4-space indentation, and no tabs.4 spaces are a good compromise between small indentation (allows greaternesting depth) and large indentation (easier to read).