Chapter 14: Advanced and Specialized Topics

Program 14.1, page no. 592

import string
import sys

print "Enter a character: ",
ch = raw_input()

if ch.isalnum():
    if ch.isdigit():
        print "You entered the digit ", ch
    elif ch.islower():
        print "You entered a lower case ", ch.upper()
    elif ch.isupper():
        print "You entered a upper case ", ch.lower()
    elif ch in string.punctuation:
        print "You entered a punctuation character ", ch
    else:
        print "You entered ", ch, "but I don't know what it is!"

Enter a character: g
 You entered a lower case  G

Program 14.2, page no. 596

print "Enter a string of less than 100 characters: ",
text = raw_input()

print "Enter the string sought: ",
sought = raw_input()
sought = sought.lower()
count = 0

sought_len = len(sought)

for i in range(len(text)):
    substr = text[i:sought_len+i]
    if substr == sought:
        count += 1

print "First string entered: ", text
print "Second string entered: ", sought
print "The second string was found in first %d times" %count

Enter a string of less than 100 characters: Smith, where Jones had had, "had", had had "had had". Enter the string sought (less than 40 characters): Had
 Enter the string sought: had
 First string entered:  Smith, where Jones had had, "had", had had "had had". Enter the string sought (less than 40 characters): Had
Second string entered:  had
The second string was found in first 7 times

Program 14.3, page no. 606

cx = 1.0 + 3.0j
cy = 1.0 - 4.0j

sum = cx + cy
diff = cx - cy
product = cx * cy
quotient = cy/cy
conjugate = cx.conjugate()

print "Complex numbers are supported"
print "Working with complex numbers: "
print "Starting values: cx = %.2f%+.2fi cy = %.2f%+.2fi" %(cx.real, cx.imag, cy.real, cy.imag)
print "The sum cx + cy = %.2f%+.2fi" %(sum.real, sum.imag)
print "The difference cx - cy = %.2f%+.2fi" %(diff.real, diff.imag)
print "The product cx * cy = %.2f%+.2fi" %(product.real, product.imag)
print "The quotient cx / cy = %.2f%+.2fi" %(quotient.real, quotient.imag)
print "The conjugate of cx = %.2f%+.2fi" %(conjugate.real, conjugate.imag)

Complex numbers are supported
Working with complex numbers: 
Starting values: cx = 1.00+3.00i cy = 1.00-4.00i
The sum cx + cy = 2.00-1.00i
The difference cx - cy = 0.00+7.00i
The product cx * cy = 13.00-1.00i
The quotient cx / cy = 1.00-0.00i
The conjugate of cx = 1.00-3.00i

Program 14.4, page no. 610

from threading import Thread

def get_data(pdata):
    pd = pdata
    print "The get_data thread received: data.a=%d and data.b=%d" %(pd[0], pd[1])
    pd[0] *= 3
    print "The get_data thread makes it: data.a=%d and data.b=%d " %(pd[0], pd[1])
 
def process_data(pdata):
    pd = pdata
    print "The process_data thread received: data.a=%d and data.b=%d "%(pd[0], pd[1])
 
mydata = [123, 345]
print "Before starting the get_data thread: mydata.a=%d and mydata. b=%d" %(mydata[0], mydata[1])
print "get_data thread started."
t1 = Thread(target=get_data, args=(mydata,))
t1.start()
Thread.join(t1)
print "process_data thread started."
t2 = Thread(target=process_data, args=(mydata,))
t2.start()
Thread.join(t2)
print "After both threads finish executing: mydata.a=%d and mydata. b=%d" %(mydata[0], mydata[1])

Before starting the get_data thread: mydata.a=123 and mydata. b=345
get_data thread started.
The get_data thread received: data.a=123 and data.b=345
The get_data thread makes it: data.a=369 and data.b=345 
process_data thread started.
The process_data thread received: data.a=369 and data.b=345 
After both threads finish executing: mydata.a=369 and mydata. b=345

Program 14.5, page no. 616

from threading import Thread
import math
import time

thread_count = 5

thread_id = []
task = 0

def execute_task():
    global task
    task += 1
    print "Task %d started." %task
    time.sleep(1)
    for i in range(1000000):
        x = math.sqrt(3.1415926)
    print "Task %d finished" %task
 

for i in range(thread_count):
    thread_id.append(Thread(target=execute_task))
    thread_id[i].start()
    
for j in range(thread_count):
    Thread.join(thread_id[j])

Task 1 started.
Task 2 started.
Task 3 started.
Task 4 started.
Task 5 started.
Task 5 finished
Task 5 finished
Task 5 finished
Task 5 finished
Task 5 finished