hasattr() function in python with example

 Python hasattr() function in python return the true if the object gives the name of attribute and false if didn't return the name.

Syntax for hasattr()

hasattr(object, name)

hasattr() in python called by the getattr() to check about the error

Parameters For hasattr() function in python

There are two parameters which is used for this function the first one is object whose name is going to be checked.

And the name is second parameter which give the name for searched

Return value

It gives boolean return value True and False

Program Example For hasattr() in Python

class Person:
    age = 22
    name = 'Adam stiffman'

person = Person()

print('Person has age?:', hasattr(person, 'age'))
print('Person has salary?:', hasattr(person, 'salary'))

Output

Person has age?: True
Person has salary?: False

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Use of Range Function In Python With Program

 python range function in python return the sequence of numbers between the start integer value to the stop integer.

Syntax : -

range(stop)
range(start, stop[, step])

Parameters For range() function in python:-

Range function takes the three arguments which is given below :-

•  first one is a start point which define the starting point of range function.
• second one is stop point integer which help to tell the end point for the sequence.
• Step is a third one and it use to define the increment for the sequence of number.

Return value from range function in python: -

•  range() function return the immutable sequence of number.

• In this function sequence of number starts form 0 to Stop-1.

• if the step argument is then it raise an Value Error.

How to use the range function in python with program

# empty range
print(list(range(0)))

# using range(stop)
print(list(range(10)))

# using range(start, stop)
print(list(range(1, 10)))

Output:

range function program in python

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fmincon Matlab Function With fmincon Example

fmincon function in MATLAB is used to find the minimum of any given nonlinear multivariable function.

MATLAB Syntax : - 

 

MATLAB Syntax

Description For fmincon MATLAB

 Nonlinear programming solver.

Let see the a problem here and find the minimum value for this problem.

fmincon MATLAB

 Well b and beq are vectors, A and Aeq are matrices in this given equation on the other hand c(x) and ceq(x) are the functions in equation that return vectors.

well as you can see in the equation f(x) is a function which returns a scalar and remember all the three function f(x),ceq(x), and c(x) are non linear.

lb,x and ub can be passed as vectors or matrices in the fmincon MATLAB.

•  x = fmincon(fun,xθ,A,b) function is started with the xθ (x theta) and try to find the minimizer x for the given function and the expression for this  A*x ≤ b. xθ can be a scalar, vector, or matrix.
  

•  x = fmincon(fun,x0,A,b,Aeq,beq) minimize this function to linear equalities Aeq*x = beq and A*x ≤ b.If there is no inequalities exist, then set A = [] and b = [].

• x = fmincon(fun,x0,A,b,Aeq,beq,lb,ub) helps to define the lower and the upper case on the design variables in x, that's why the solution always exixt in between lb ≤ x ≤ ub.

x = fmincon(fun,x0,A,b,Aeq,beq,lb,ub,nonlcon) will helps to minimization to the nonlinear inequalities c(x) or the equalities ceq(x) defined in nonlcon.

 

x = fmincon(fun,x0,A,b,Aeq,beq,lb,ub,nonlcon,options) function helps to minimizes with the optimization options which is specified in options.

x = fmincon(problem) helps to finds the minimum for the given problem, and a structure described in problem.

 

[x,fval,exitflag,output] = fmincon(___) will helps to return a value exitflag that describes the exit condition of fmincon function MATLAB.

Example for fmincon function MATLAB

Find the minimum value of Rosenbrock's function if there is a linear inequality constraint. 

 

 

Example for fmincon function MATLAB

 

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sprintf Function In MATLAB With Example Program

 stg = sprintf(formatSpec,B1,...,Bn) use to formats the data in an array with the help of  formatting operators which is specified by formatSpec in MATLAB and returns the resulting text in a define variable(stg) then stg known as output and otherwise stg is an character.

MATLAB Program for Literal Text and Array Inputs

formatSpec = 'The array is %dx%d.';
A1 = 2;
A2 = 3;
str = sprintf(formatSpec,A1,A2)

Program example for MATLAB

 

compose function is used to return the number of pieces of formatted text as a string array and that can be used with the MATLAB sprintf() Function.

str = sprintf(literalText) In MATLAB use to translates escape-character sequences of the literalText which is define with sprintf function in MATLAB for example :-  \n and \t and sprint function return the all other  characters unaltered.

Now if the string contain any  formatting operator (example %f) then sprint function in MATLAB discards it and all characters after that operator. 

Input Arguments for sprintf function in MATLAB

• The Output is format with the help of  formatSpec and this also include the ordinary text and special characters.

• if  formatSpec is include the escape characters in string then  sprintf Function translates that escape characters (such as /n).

Formatting Operator of sprintf

A formatting operator for sprintf starts with a percent sign, %, and ends with a conversion character and the conversion character is also required.

You can also specified some identifier like subtype operators, field width, precision, and  flags between % and  conversion character which is an end point.

Read more  : -  fmincon Matlab Function

List Of Conversion Character for Sprintf function in MATLAB

There some of the Conversion Character

Conversion Character for Sprintf function

Some tips : - 

    The sprintf function in MATLAB is similar to fprintf function but the fprintf function is used for the Command Window.

 

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fprintf command And fprintf format in MATLAB

•  The fprintf command in MATLAB Programming use to displays formatted text which is centered on the icon and this fprint function can display formatSpec with a contents of var.

• formatSpec  in MATLAB can be a character vector with the single quotes, or a string scalar.

Formatting for the fprint function in MATLAB : -

•  formatting is starts with the a percentage sign, % and it will end with the conversion character.

• Remember conversion character is required in formatting Operator.

• But you can use the  flags, field , identifier,width, and subtype,precision operators between % and conversion character.
  

 List for the Conversion Character

Conversion Character in MATLAB

Example of fprint function in MATLAB

The command

fprintf('YES YES');

displays this text 'YES YES' on the icon.

The follow command

fprintf('YES YES = %d',16);

uses the decimal notation format (%d) to display the variable 16.

Using fprintf in MATLAB With Function

Let's see this example for define a function in MATLAB : -

function []= fun2let(n)
 if n > 90.00
 fprintf('>>letter grade to %d is:A+\n',n)
 elseif n<=89.49 && n>=80.00
 fprintf('>>letter grade to %d is:B+\n',n)
 % YOU COMPLETE YOUR FUNCTION WITH OTHER TESTS
 elseif n<59.5 
 %    grade='Fail'
    fprintf('>> letter grade to %d is:Fail\n',n)
 end
 end

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frozenset() function in python With Example Code - Python Function

•  The frozenset() function in python is an inbuilt function is Python.

• That Function takes an iterable object as input and makes them immutable. 

• it freezes the iterable objects and makes them unchangeable.
• frozen sets can be helpful in  Dictionary it can be used as key because it remain the same after creation.
  

Parameter for the  frozenset() function in Python

it use a single parameter iterable which can be ( dictionary, tuple, etc.)

Return value : - 

• The frozenset() function in python returns an immutable frozenset.

• it return the empty frozenset only if no parameters are passed to this function.

Example code for frozenset function in python :- 

# tuple of vowels
vowels = ('a', 'e', 'i', 'o', 'u')

fset = frozenset(vowels)
print('The frozen set is:', fset)
print('The empty frozen set is:', frozenset())

# frozensets are immutable
fSet.add('v')

OUTPUT

Example code for frozenset

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fft matlab Function And ftt code with Example

 Fast Fourier transform of fft function in matlab.

Syntax:-

Y = fft(X)
Y = fft(X,n)
Y = fft(X,n,dim)

Discprition for fft matlab Function

If x is an vector then it will return the Fourier transform of that vector

Let x is an matrix then fft(X) assume the colum as a vactory and return Fourier transform of each column.

Now let assume X is an multidimensional array then fft(X) treats the values of first array dimension only if the size of that array is not equal to 1 as vector and gives the Fourier transform of each vector

Cases with the fft() MATLAB Function

Y = fft(X,n) returns the n-point DFT.

Case 1

X is an vector and the length of X is lower then n. X will be padded with trailing zeros to length n

Case 2

X is an vector and the length of X is Higher then n. X will be truncated to length n

Case 2

X is an matrix then each column of that matrix treated as in the vector case

Case 2

multidimensional array X is treated as like fft(X) the "first array dimension only if the size of that array is not equal to 1" treated as in the vector case

Y = fft(X,n,dim) gives the Fourier transform along with the dimension dim.

Example Code For ftt() function in MATLAB

Use the help of Fourier transforms to find the frequency components of a signal buried in noise.

Fs = 1000;            % Sampling frequency                    
T = 1/Fs;             % Sampling period       
L = 1500;             % Length of signal
t = (0:L-1)*T;        % Time vector

Form a signal containing a 50 Hz sinusoid of amplitude 0.7 and a 120 Hz sinusoid of amplitude 1.

S = 0.7*sin(2*pi*50*t) + sin(2*pi*120*t);

Corrupt the signal with zero-mean white noise with a variance of 4.

X = S + 2*randn(size(t));

Plot the noisy signal in the time domain. It is difficult to identify the frequency components by looking at the signal X(t).

plot(1000*t(1:50),X(1:50))
title('Signal Corrupted with Zero-Mean Random Noise')
xlabel('t (milliseconds)')
ylabel('X(t)')


Compute the Fourier transform of the signal.

Y = fft(X);

Compute the two-sided spectrum P2. Then compute the single-sided spectrum P1 based on P2 and the even-valued signal length L.

P2 = abs(Y/L);
P1 = P2(1:L/2+1);
P1(2:end-1) = 2*P1(2:end-1);

Define the frequency domain f and plot the single-sided amplitude spectrum P1. The amplitudes are not exactly at 0.7 and 1, as expected, because of the added noise. On average, longer signals produce better frequency approximations.

f = Fs*(0:(L/2))/L;
plot(f,P1) 
title('Single-Sided Amplitude Spectrum of X(t)')
xlabel('f (Hz)')
ylabel('|P1(f)|')

Now, take the Fourier transform of the original, uncorrupted signal and retrieve the exact amplitudes, 0.7 and 1.0.

Y = fft(S);
P2 = abs(Y/L);
P1 = P2(1:L/2+1);
P1(2:end-1) = 2*P1(2:end-1);

plot(f,P1) 
title('Single-Sided Amplitude Spectrum of S(t)')
xlabel('f (Hz)')
ylabel('|P1(f)|')

OUTPUT For Example of fft () matlab:-

fft () matlab output

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fftshift matlab

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fourier transform matlab

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