代写代考 QUT2020_22/teaching/Sem1_2022/IFN647/wk2_lec’

Week 2 Python Introduction¶

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# define a string s
s = ‘First line.\nSecond line.’

# print the string, \n means a new line
print(len(s)) # print the length of the string

First line.
Second line.

# get elements or sub-string of the string

# test string methods
s.split(sep=’\n’, maxsplit=-1)

[‘First line.’, ‘Second line.’]

s.istitle()

s.isalpha()

s1=’first’
s1.isalpha()

s1.istitle()

s2=’First Second’
s2.isalpha()

spam = ‘Hello world!’
spam.istitle()

spam = ‘Hello World!’
spam.istitle()

s=’-‘.join([‘My’, ‘Name’, ‘is’, ‘John’])
s.split(sep=’-‘, maxsplit=-1)

[‘My’, ‘Name’, ‘is’, ‘John’]

s.strip(‘n’)

‘My-Name-is-Joh’

s = ‘## My # name is #’
s.strip(‘#’)

‘ My # name is ‘

s.replace(‘#’, ‘%’, 3)

‘%% My % name is #’

spam = ‘HellO WOrld!’
spam.replace(‘O’, ‘o’, 1)

‘Hello WOrld!’

mystr = ‘ ?’
mappingtbl = mystr.maketrans(‘M?’,’H!’)
newstr = mystr.translate(mappingtbl) # pass mapping table in translate()
print(newstr)

Hello World!

# simple program

print(‘Hello’)
print(‘What\’s your name?’)
yourName=input()
print(‘It is good to meet you,’ + yourName) #yourName must be a string?
print(‘The length of your name is\n’)
print(len(yourName))

What’s your name?
It is good to meet you,”Yuefeng”
The length of your name is

# if statements
x = int(input(“Please enter an integer: “))
print(‘Negative changed to zero’)
elif x == 0:
print(‘Zero’)
elif x == 1:
print(‘Single’)
print(‘More’)

Please enter an integer: 1

# for loops
words = [‘cat’, ‘window’, ‘defenestrate’]
for w in words:
print(w, len(w))

defenestrate 12

# use range
a = [‘Mary’, ‘had’, ‘a’, ‘little’, ‘lamb’]
for i in range(len(a)): # or range(0, len(a))
print(i, a[i])

# write Fibonacci series up to 100
a, b = 0, 1
while a < n: print(a, end=' ') a, b = b, a+b print('the_end') # break statement your_pwd = 'qut2020' while True: print('Enter your password:') input_pwd = input() if input_pwd == your_pwd: print('I got it!') 0 1 1 2 3 5 8 13 21 34 55 89 the_end Enter your password: # for loops cont. for num in range(2, 10): if num % 2 == 0: print("Found an even number", num) print("Found a number", num) Found an even number 2 Found a number 3 Found an even number 4 Found a number 5 Found an even number 6 Found a number 7 Found an even number 8 Found a number 9 '__builtin__', '__builtins__', '__doc__', '__loader__', '__name__', '__package__', '__spec__', 'get_ipython', 'input_pwd', 'mappingtbl', 'yourName', 'your_pwd'] # import random in two ways print('The 1st:') import random x = random.randint(1,10) print('The 2nd:') from random import randint y = randint(1,10) def fib(n): # Fibonacci function x, y = 0, 1 fib_list = [] while x < n: fib_list.append(x) x, y = y, x+y return(fib_list) # test the function print(fib(0)) print(fib(100)) print(fib(2000)) [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89] [0, 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, 144, 233, 377, 610, 987, 1597] # use except def spam(divideBy): return 100/ divideBy except ZeroDivisionError: print('Error: invalid denominator') # test spam function Error: invalid denominator 8.333333333333334 # list comprehension [(x,y) for x in [1,2,3] for y in [3,1,4] if x!=y] [(1, 3), (1, 4), (2, 3), (2, 1), (2, 4), (3, 1), (3, 4)] # python dictionary (dict) tel = {'jack': 4098, 'sape': 4139} tel['guido'] = 4127 #insert {'jack': 4098, 'sape': 4139, 'guido': 4127} ['jack', 'sape', 'guido'] sorted(tel) ['guido', 'jack', 'sape'] 'jack' not in tel 'sape' in tel # list to dict dict([('John', 4130), ('lee', 5212)]) {'John': 4130, 'lee': 5212} # dict comprehension nd = {x: x**2 for x in (2, 4, 6)} {2: 4, 4: 16, 6: 36} nd[8] = 64 {2: 4, 4: 16, 6: 36, 8: 64} tel['jack'] {'jack': 4098, 'sape': 4139, 'guido': 4127} # loop to access dictionary for (k, v) in tel.items(): print(k,v) guido 4127 for v in tel.values(): for k in tel.keys(): # define class class MyClass: """A simple example class""" def __init__(self, myList): self.data = myList def f(self): return 'hello world' # test the define class mc = MyClass([2,3,0]) print(mc.i) print(mc.f()) print(mc.data) mc.data = [1,2,3,4] print(mc.data) hello world [1, 2, 3, 4] # class cont. class Node: def __init__(self, data, next=None): self.data=data self.next=next class Linkedlist: def __init__(self, hnode): self.head=hnode def insert(self, nnode): if self.head != None: p = self.head while p.next != None: p.next=nnode def lprint(self): if self.head != None: p = self.head while p!= None: print(p.data,end =" " ) if p.next != None: print ('-->‘, end=” “)
print(‘The list is empty!’)

myList = Linkedlist(Node(“A”, None))
myList.insert(Node(‘B’, None))
myList.insert(Node(‘C’, None))
myList.lprint()

A –> B –> C

# test os package

os.path.join(‘usr’, ‘bin’, ‘spam’)

‘usr/bin/spam’

myFiles = [‘acounts.txt’, ‘details.csv’, ‘invite.doc’]
for fn in myFiles:
print(os.path.join(‘/users/li’, fn))

/users/li/acounts.txt
/users/li/details.csv
/users/li/invite.doc

# get your current working folder
os.getcwd()

‘/Users/li3/Desktop/QUT2020_22/teaching/Sem1_2022/IFN647/wk2_lec’

# open a file and read its contents
xmlFile = open(‘6146.xml’)
xmlContent = xmlFile.read() # also check readlines()
words = xmlContent.split(‘\n’)
# print each paragraphs separated by newline
for w in words:
#print all paragraphs that start with ‘


Argentine bonds stage slight technical bounce.
BUENOS AIRES 1996-08-21

Argentine bonds were slightly higher in a small technical bounce Wednesday amid low volume.

A trader at a large foreign bank said there was a slight technical bounce at the opening, and he did not expect prices to change much during the session as no market-moving news is expected.

The 5.5 percent dollar-denominated 2 due 2001 rose $0.15 to 115.15. Argentina’s FRB due 2005 rose 1/8 to 77-3/8.

"There is general uncertainty," said the trader, pointing to all the events the market is waiting for, including the passage of the government’s new economic measures through Congress, which is now not expected until early October.

In addition, traders are awaiting a meeting Friday between Economy Minister and an International Monetary Fund delegation on Argentina’s fiscal deficit.

— , Buenos Aires Newsroom, 541 318-0668

(c) Reuters Limited 1996