I'm new to computer programming and I'm trying to write a program that converts English into Pig Latin (For every word, move the first letter to the end of the word and add 'ay').
If the there is a number (in digits), multiply it by 2 and add 4.
ex. John has 4 cats --> ndaay ashay 12 atscay)
I got the first pig latin part down but can't seem to figure out the number part. My code accesses a text file but here is the program that would perform the string pig-latin. Where would I fit the number function?
def pig_english():
letterlist = [i + i[0] for i in read_script()]
ayList = [i + 'ay' for i in letterlist]
delaylist = [i[1:] for i in ayList]
print (delaylist)
You can test if i.isdigit() and then cast to an int but it will be easier doing it all in one comprehension:
def pig_english(words):
ayList = [str(int(i)*2+4) if i.isdigit() else i[1:]+i[0]+"ay" for i in words]
print (ayList)
If you split the operations across multiple comprehensions then you will need to guard against ints:
def pig_english(words):
numberlist = [int(i)*2+4 if i.isdigit() else i for i in words]
letterlist = [i if isinstance(i, int) else i + i[0] for i in numberlist]
ayList = [i if isinstance(i, int) else i + 'ay' for i in letterlist]
delaylist = [str(i) if isinstance(i, int) else i[1:] for i in ayList]
print (delaylist)
>>> pig_english("John has 4 cats".split())
['ohnJay', 'ashay', '12', 'atscay']
Related
trying to write this code to see how many times the numbers in list 1 appear in the list two, can use a nested for or while loop but I came up with this it doesn't work. I don't want to use count.
list1 = [4,7,2]
list2 = [2,3,4,2,5,6,3,2,6,7,3,4]
def compare(list1, list2):
freq = ([i for i in list1 if i == num])
return
print('The number 4 occurs in list2', freq, 'times')
print('The number 7 occurs in list2', freq, 'times')
print('The number 2 occurs in list2', freq, 'times')
I'm not completely sure that I understand the question,
but this code seems to work, though if it may be slow if you need it for an interactive program.
Hope this helps!
list1 = [4,7,2]
list2 = [2,3,4,2,5,6,3,2,6,7,3,4]
occurrences = [0,0,0]
for i in range(len(list1)):
for j in list2:
if list1[i] == j:
occurrences[i]+=1
print occurrences
try this:
list1 = [4,7,2]
list2 = [2,3,4,2,5,6,3,2,6,7,3,4]
occurrences = [0,0,0]
for i in range(len(list1)):
for j in list2:
if list1[i] == j:
occurrences[i]+=1
print occurrences
Im taking an online beginner course through google on python 2, and I cannot figure out the answer to one of the questions. Here it is and thanks in advance for your help!
# A. match_ends
# Given a list of strings, return the count of the number of
# strings where the string length is 2 or more and the first
# and last chars of the string are the same.
# Note: python does not have a ++ operator, but += works.
def match_ends(words):
a = []
for b in words:
return
I tried a few different things. This is just where i left off on my last attempt, and decided to ask for help. I have spent more time thinking about this than i care to mention
def match_ends(words):
a = []
for b in words:
if (len(b) > 2 and b[0] == b[len(b)-1]):
a.append(b)
return a
def match_ends2(words):
return [x for x in words if len(x) > 2 and x[0] == x[len(x)-1]]
print(match_ends(['peter','paul','mary','tibet']))
print(match_ends2(['peter','paul','mary','tibet']))
user = int(raw_input("Type 5 numbers"))
even = []
def purify(odd):
for n in odd:
even.append(n)
if n % 2 > 0:
print n
print purify(user)
Hello I am a beginner and I would like to understand what is wrong with this code.
The User chose 5 numers and I want to print the even numbers only.
Thanks for helping
There are a few problems:
You can't apply int to an overall string, just to one integer at a time.
So if your numbers are space-separated, then you should split them into a list of strings. You can either convert them immediately after input, or wait and do it within your purify function.
Also, your purify function appends every value to the list even without testing it first.
Also, your test is backwards -- you are printing only odd numbers, not even.
Finally, you should return the value of even if you want to print it outside the function, instead of printing them as you loop.
I think this edited version should work.
user_raw = raw_input("Type some space-separated numbers")
user = user_raw.split() # defaults to white space
def purify(odd):
even = []
for n in odd:
if int(n) % 2 == 0:
even.append(n)
return even
print purify(user)
raw_input returns a string and this cannot be converted to type int.
You can use this:
user = raw_input("Input 5 numbers separated by commas: ").split(",")
user = [int(i) for i in user]
def purify(x):
new_lst = []
for i in x:
if i % 2 == 0:
new_lst.append(i)
return new_lst
for search even
filter would be the simplest way to "filter" even numbers:
output = filter(lambda x:~x&1, input)
def purify(list_number):
s=[]
for number in list_number:
if number%2==0:
s+=[number]
return s
I'm working through the book NLP with Python, and I came across this example from an 'advanced' section. I'd appreciate help understanding how it works. The function computes all possibilities of a number of syllables to reach a 'meter' length n. Short syllables "S" take up one unit of length, while long syllables "L" take up two units of length. So, for a meter length of 4, the return statement looks like this:
['SSSS', 'SSL', 'SLS', 'LSS', 'LL']
The function:
def virahanka1(n):
if n == 0:
return [""]
elif n == 1:
return ["S"]
else:
s = ["S" + prosody for prosody in virahanka1(n-1)]
l = ["L" + prosody for prosody in virahanka1(n-2)]
return s + l
The part I don't understand is how the 'SSL', 'SLS', and 'LSS' matches are made, if s and l are separate lists. Also in the line "for prosody in virahanka1(n-1)," what is prosody? Is it what the function is returning each time? I'm trying to think through it step by step but I'm not getting anywhere. Thanks in advance for your help!
Adrian
Let's just build the function from scratch. That's a good way to understand it thoroughly.
Suppose then that we want a recursive function to enumerate every combination of Ls and Ss to make a given meter length n. Let's just consider some simple cases:
n = 0: Only way to do this is with an empty string.
n = 1: Only way to do this is with a single S.
n = 2: You can do it with a single L, or two Ss.
n = 3: LS, SL, SSS.
Now, think about how you might build the answer for n = 4 given the above data. Well, the answer would either involve adding an S to a meter length of 3, or adding an L to a meter length of 2. So, the answer in this case would be LL, LSS from n = 2 and SLS, SSL, SSSS from n = 3. You can check that this is all possible combinations. We can also see that n = 2 and n = 3 can be obtained from n = 0,1 and n=1,2 similarly, so we don't need to special-case them.
Generally, then, for n ≥ 2, you can derive the strings for length n by looking at strings of length n-1 and length n-2.
Then, the answer is obvious:
if n = 0, return just an empty string
if n = 1, return a single S
otherwise, return the result of adding an S to all strings of meter length n-1, combined with the result of adding an L to all strings of meter length n-2.
By the way, the function as written is a bit inefficient because it recalculates a lot of values. That would make it very slow if you asked for e.g. n = 30. You can make it faster very easily by using the new lru_cache from Python 3.3:
#lru_cache(maxsize=None)
def virahanka1(n):
...
This caches results for each n, making it much faster.
I tried to melt my brain. I added print statements to explain to me what was happening. I think the most confusing part about recursive calls is that it seems to go into the call forward but come out backwards, as you may see with the prints when you run the following code;
def virahanka1(n):
if n == 4:
print 'Lets Begin for ', n
else:
print 'recursive call for ', n, '\n'
if n == 0:
print 'n = 0 so adding "" to below'
return [""]
elif n == 1:
print 'n = 1 so returning S for below'
return ["S"]
else:
print 'next recursivly call ' + str(n) + '-1 for S'
s = ["S" + prosody for prosody in virahanka1(n-1)]
print '"S" + each string in s equals', s
if n == 4:
print '**Above is the result for s**'
print 'n =',n,'\n', 'next recursivly call ' + str(n) + '-2 for L'
l = ["L" + prosody for prosody in virahanka1(n-2)]
print '\t','what was returned + each string in l now equals', l
if n == 4:
print '**Above is the result for l**','\n','**Below is the end result of s + l**'
print 'returning s + l',s+l,'for below', '\n','='*70
return s + l
virahanka1(4)
Still confusing for me, but with this and Jocke's elegant explanation, I think I can understand what is going on.
How about you?
Below is what the code above produces;
Lets Begin for 4
next recursivly call 4-1 for S
recursive call for 3
next recursivly call 3-1 for S
recursive call for 2
next recursivly call 2-1 for S
recursive call for 1
n = 1 so returning S for below
"S" + each string in s equals ['SS']
n = 2
next recursivly call 2-2 for L
recursive call for 0
n = 0 so adding "" to below
what was returned + each string in l now equals ['L']
returning s + l ['SS', 'L'] for below
======================================================================
"S" + each string in s equals ['SSS', 'SL']
n = 3
next recursivly call 3-2 for L
recursive call for 1
n = 1 so returning S for below
what was returned + each string in l now equals ['LS']
returning s + l ['SSS', 'SL', 'LS'] for below
======================================================================
"S" + each string in s equals ['SSSS', 'SSL', 'SLS']
**Above is the result for s**
n = 4
next recursivly call 4-2 for L
recursive call for 2
next recursivly call 2-1 for S
recursive call for 1
n = 1 so returning S for below
"S" + each string in s equals ['SS']
n = 2
next recursivly call 2-2 for L
recursive call for 0
n = 0 so adding "" to below
what was returned + each string in l now equals ['L']
returning s + l ['SS', 'L'] for below
======================================================================
what was returned + each string in l now equals ['LSS', 'LL']
**Above is the result for l**
**Below is the end result of s + l**
returning s + l ['SSSS', 'SSL', 'SLS', 'LSS', 'LL'] for below
======================================================================
This function says that:
virakhanka1(n) is the same as [""] when n is zero, ["S"] when n is 1, and s + l otherwise.
Where s is the same as the result of "S" prepended to each elements in the resulting list of virahanka1(n - 1), and l the same as "L" prepended to the elements of virahanka1(n - 2).
So the computation would be:
When n is 0:
[""]
When n is 1:
["S"]
When n is 2:
s = ["S" + "S"]
l = ["L" + ""]
s + l = ["SS", "L"]
When n is 3:
s = ["S" + "SS", "S" + "L"]
l = ["L" + "S"]
s + l = ["SSS", "SL", "LS"]
When n is 4:
s = ["S" + "SSS", "S" + "SL", "S" + "LS"]
l = ["L" + "SS", "L" + "L"]
s + l = ['SSSS", "SSL", "SLS", "LSS", "LL"]
And there you have it, step by step.
You need to know the results of the other function calls in order to calculate the final value, which can be pretty messy to do manually as you can see. It is important though that you do not try to think recursively in your head. This would cause your mind to melt. I described the function in words, so that you can see that these kind of functions is are descriptions, and not a sequence of commands.
The prosody you see, that is a part of s and l definitions, are variables. They are used in a list-comprehension, which is a way of building lists. I've described earlier how this list is built.
I am trying to create a code that takes the user input, compares it to a list of tuples (shares.py) and then prints the values in a the list. for example if user input was aia, this code would return:
Please list portfolio: aia
Code Name Price
AIA Auckair 1.50
this works fine for one input, but what I want to do is make it work for multiple inputs.
For example if user input was aia, air, amp - this input would return:
Please list portfolio: aia, air, amp
Code Name Price
AIA Auckair 1.50
AIR AirNZ 5.60
AMP Amp 3.22
This is what I have so far. Any help would be appreciated!
import shares
a=input("Please input")
s1 = a.replace(' ' , "")
print ('Please list portfolio: ' + a)
print (" ")
n=["Code", "Name", "Price"]
print ('{0: <6}'.format(n[0]) + '{0:<20}'.format(n[1]) + '{0:>8}'.format(n[2]))
z = shares.EXCHANGE_DATA[0:][0]
b=s1.upper()
c=b.split()
f=shares.EXCHANGE_DATA
def find(f, a):
return [s for s in f if a.upper() in s]
x= (find(f, str(a)))
print ('{0: <6}'.format(x[0][0]) + '{0:<20}'.format(x[0][1]) + ("{0:>8.2f}".format(x[0][2])))
shares.py contains this
EXCHANGE_DATA = [('AIA', 'Auckair', 1.5),
('AIR', 'Airnz', 5.60),
('AMP', 'Amp',3.22),
('ANZ', 'Anzbankgrp', 26.25),
('ARG', 'Argosy', 12.22),
('CEN', 'Contact', 11.22)]
I am assuming a to contain values in the following format 'aia air amp'
raw = a # just in case you want the original string at a later point
toDisplay = []
a = a.split() # a now looks like ['aia','air','amp']
for i in a:
temp = find(f, i)
if(temp):
toDisplay.append(temp)
for i in toDisplay:
print ('{0: <6}'.format(i[0][0]) + '{0:<20}'.format(i[0][1]) + ("{0:>8.2f}".format(i[0][2])))
Essentially what I'm trying to do is
Split the input into a list
Do exactly what you were doing for a single input for each item in that list
Hope this helps!