Welcome to Python Programming Language Part 2. In this article we are briefing you all about the python programming language basics . The output from the chaos program may not look very exciting, but it illustrates a very interesting phenomenon known to physicists and mathematicians. Let’s take a look at this program line by line and see what it does. Don’t worry about understanding every detail right away; we will be returning to all of these ideas in the next chapter. The first two lines of the program start with the # character: # File: chaos.py # A simple program illustrating chaotic behavior. These lines are called comments. They are intended for human readers of the program and are ignored by Python. The Python interpreter always skips any text from the pound sign (#) through the end of a line. The next line of the program begins the definition of a function called main. def main(): Strictly speaking, it would not be necessary to create a main funct...
In this blog today we are going to learn about python programming and its basic and what's its purpose? We have given introduction about programming language and how it works.
Remember
that a program is just a sequence of instructions telling a computer what to
do. Obviously, we need to provide those instructions in a language that a
computer can understand. It would be nice if we could just tell a computer what
to do using our native language, like they do in science fiction movies.
(“Computer, how long will it take to reach planet Alphalpha at maximum warp?”)
Unfortunately, despite the continuing efforts of many top-flight computer
scientists, designing a computer to understand human language is still an
unsolved problem.
Even if computers could understand us, human
languages are not very well suited for describing complex algorithms. Natural
language is fraught with ambiguity and imprecision. For example, if I say: “I
saw the man in the park with the telescope,” did I have the telescope, or did
the man? And who was in the park? We understand each other most of the time
only because all humans share a vast store of common knowledge and experience.
Even then, miscommunication is commonplace. Computer scientists have gotten
around this problem by designing notations for expressing computations in an
exact, and unambiguous way. These special notations are called programming
languages. Every structure in a programming language has a precise form (its
syntax) and a precise meaning (its semantics).
A programming language is something like a
code for writing down the instructions that a computer will follow. In fact,
programmers often refer to their programs as computer code, and the process of
writing an algorithm in a programming language is called coding. Python is one
example of a programming language. You may have heard of some other languages,
such as C++, Java, Perl, Scheme, or BASIC. Although these languages differ in
many details, they all share the property of having well-defined, unambiguous
syntax and semantics. All of the languages mentioned above are examples of
high-level computer languages. Although they are precise, they are designed to
be used and understood by humans. Strictly speaking, computer hardware can only
understand very low-level language known as machine language. Suppose we want
the computer to add two numbers. The instructions that the CPU actually carries
out might be something like this.
Load the
number from memory location 2001 into the CPU load the number from memory
location 2002 into the CPU Add the two numbers in the CPU store the result into
location 2003
This seems
like a lot of work to add two numbers, doesn’t it? Actually, it’s even more
complicated than this because the instructions and numbers are represented in
binary notation (as sequences of 0s and 1s). In a high-level language like
Python, the addition of two numbers can be expressed more naturally: c = a + b.
That’s a lot easier for us to understand, but we need some way to translate the
high-level language into the machine language that the computer can execute.
There are
two ways to do this: a high-level language can either be compiled or
interpreted. A compiler is a complex computer program that takes another
program written in a high-level language and translates it into an equivalent
program in the machine language of some computer. The high-level program is
called source code, and the resulting machine code is a program that the computer
can directly execute.
The dashed
line in the diagram represents the execution of the machine code. An
interpreter is a program that simulates a computer that understands a
high-level language. Rather than translating the source program into a machine language
equivalent, the interpreter analyses and executes the source code instruction
by instruction as necessary. The difference between interpreting and compiling
is that compiling is a one-shot translation; once a program is compiled, it may
be run over and over again without further need for the compiler or the source
code. In the interpreted case, the interpreter and the source are needed every
time the program runs.
Compiled
programs tend to be faster, since the translation is done once and for all, but
interpreted languages lend themselves to a more flexible programming environment
as programs can be developed and run interactively. The translation process
highlights another advantage that high-level languages have over machine
language: portability. The machine language of a computer is created by the
designers of the particular CPU.
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