As Keyword In Python

Overview:

The as clause in python is used in the following contexts:

  • Accompanied by the with statement to name the resource being allocated

  • In the from…import statement and the import statement as a means to bind the module to a name

  • In the except statement to associate a name to the exception being passed

As keyword in Python

Fig-1: The as keyword in Python

Example 1 - as clause used in import statement:

# as clause used to bind the name np for the numpy module

import numpy as np

 

radians = np.pi

 

# calculate sine, cosine and tan values for np.pi radians

sineValue       = np.sin(radians)

cosineValue     = np.cos(radians)

tanValue        = np.tan(radians)

 

# print the sine, cosine and tan values

print("Sine of %f radians:%f"%(radians, sineValue));

print("Cosine of %f radians:%f"%(radians, cosineValue));

print("Tangent of %f radians:%f"%(radians, tanValue));

 

Output 1:

Sine of 3.141593 radians:0.000000

Cosine of 3.141593 radians:-1.000000

Tangent of 3.141593 radians:-0.000000

 

 

Example 2 - as clause used in from import statement:

# as clause used to bind the name plot, with pyplot module from matplotlib

import numpy as np

from matplotlib import pyplot as plot

 

sampleSequence      = np.arange(0,400,10)

magnitudeSequence   = np.sin(2*np.pi*sampleSequence*1/400)

 

plot.plot(sampleSequence,magnitudeSequence)

plot.title('Sinusoid')

plot.xlabel('Sample')

plot.ylabel('Amplitude')

 

plot.show()

 

 

Output 2:

with open('sample.txt') as fileObject:

    fileContents = fileObject.read()

 

print("Text file contents:")

print(fileContents)   

 

 

Example 3 - as clause accompanied by the with statement:

with open('sample.txt') as fileObject:

    fileContents = fileObject.read()

 

print("Text file contents:")

print(fileContents)   

 

 

Output 3:

Text file contents:

sample text

 

 

Example 4 – along with except clause:

 try:

    fileContents    = ""

    with open('sample.txt') as fileObject:

        fileContents = fileObject.read()

        print("Text file contents:")

        print(fileContents)   

except FileNotFoundError as ex:

    print(ex)

 

Output 4:

[Errno 2] No such file or directory: 'sample.txt'

 

 


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