I want to write a function that will return the "rounder" looking number given two numbers.
Examples:
f(1.0001, 1) = 1
f(250, 251) = 250
f(9.74, 9.75) = 9.75
I have an intuitive idea of what is the "rounder" number but I don't know to turn that into code.
Related
I'm currently working on this problem that ask me to generate an arrow pattern using loops function that looks something like this:
"How many columns? 3"
*
*
*
*
*
I know I can do this with for loop(probably more efficient too), but that is not what I aimed for. I wanted to achieve this only using while loop.
I have some ideas:
1. I set up a control variable and an accumulator to control the loop
2. I then write 2 separate loops to generate the upper and lower part of the pattern. I was thinking about inserting the space before the asterisks using method like this:
(accumulator - (accumulator - integer)) * spaces.
#Ask the user how many column and direction of column
#they want to generate
Keep_going = True
Go = 0
while keep_going:
Column_num = int(input("How many columns? "))
if Column_num <= 0:
print("Invalid entry, try again!")
else:
print()
Go = 1
#Upper part
while Keep_going == True and Go == 1:
print("*")
print(""*(Column_num - (Column_num - 1) + "*")
...but I soon realized it wouldn't work because I don't know the user input and thus cannot manually calculate how many spaces to insert before asterisks. Now everything on the internet tells me to use for loop and range function, I could do that, but I think that is not helpful for me to learn python since I couldn't utilize loops very well yet and brute force it with some other method just not going to improve my skills.
I assume this is achievable only using while loop.
#Take your input in MyNumber
MyNumber = 5
i = 1
MyText = '\t*'
while i <=MyNumber:
print(MyText.expandtabs(i-1))
i = i+1
i = i-1
while i >=1:
print(MyText.expandtabs(i-1))
i = i-1
Python - While Loop
Well first you have to understand that a while loop loops until a requirement is met.
And looking at your situation, to determine the number of spaces before the * you should have an ongoing counter, a variable that counts how many spaces are needed before you continue. For example:
###Getting the number of columns###
while True:
number=int(input('Enter number of rows: '))
if number<=0:
print('Invalid')
else:
###Ending the loop###
break
#This will determine the number of spaces before a '*'
counter=0
#Loops until counter equals number
while counter!=number:
print(" "*counter + "*")
#Each time it loops the counter variable increases by 1
counter=counter+1
counter=counter-1
#Getting the second half of the arrow done
while counter!=0:
counter=counter-1
print(" "*counter + "*")
Please reply if this did not help you so that i can give a more detailed response
Very new to matlab and still learning the basics. I'm trying to write a script which calculates the distance between two peaks in a waveform. That part I have managed to do, and I have used xlswrite to put the values I have obtained onto an excel file.
For each file, I have between about 50-250 columns, with just two rows: the second row has the numerical value, and the first has the column headings, copied from original excel files I extracted the data from.
Some of the columns have similar, but not identical, headings, e.g. 'green227RightEyereading3' and 'green227RightEyereading4' etc. Is there a way I can group columns with similar headings, e.g. which have the same number/colour in the heading (I.e.green227) and either 'right eye' or 'left eye', and calculate an average of their numerical values? Link to file here: >https://www.dropbox.com/s/ezpyjr3raol31ts/SampleBatchForTesting.xls?dl=0>
>[Excel_file,PathName] = uigetfile('*.xls', 'Pick a File','C:\Users\User\Documents\Optometry\Year 3\Dissertation\A-scan3');
>[~,name,ext] = fileparts(Excel_file);
>sheet = 2;
>FullXLSfile = [PathName, Excel_file];
>[number_data,txt_data,raw_data] = xlsread(FullXLSfile,sheet);
>HowManyWide = size(txt_data);
>NumberOfTitles = HowManyWide(1,2);
>xlRangeA = txt_data;
>Chickens = {'Test'};
>for f = 1:xlRangeA; %%defined as top line of cells on sheet;
>Text = xlRangeA{f};
>HyphenLocations = find(Text == '-');
>R = HyphenLocations(1,1) -1;
>Chick = Text(1:R);
>Chick = cellstr(Chick);
>B = length(Chick);
>TF = strncmp(Chickens,Chick,B);
>if any(TF == 1); %do nothing
>else
>Chickens = {Chickens;Chick};
>end
>end
Here also is a link to the file that is created when I run my entire script. The values below the headings are the calculated thickesses of the tissue I'm analysing. https://www.dropbox.com/s/4p6iu9kk75ecyzl/Choroid_Thickness.xls?dl=0
Thanks very much
If the different characters are located at the very end (or the very beginning) of the heading, you can go with strncmp buit-in function and compare only part of the string. See more here. But please, provide some code and a part of your excel file. It would help.
Also, if I am not mistaken, you are saving all the data into excel and then re-call it again in order to sort it. Maybe you should consider saving only the final result in excel, it will save you some time, especially if you want to run your script many times.
EDIT:
Here is the code I came up with. It is not the best possible solution for sure, but it works with the file you uploaded. I have omitted the unnecessary lines and variables. The code works only if the numbers of each reading have the same amount of digits. They can be 4 digits as long as every entry has 4 digits. Since in each file you have waves of the same color, the only thing that you care about is whether the reading was recorded with the left or the right eye (correct?). Based on that and the code you wrote, the comparison concerns the part of the string that contains the words "Right" or "Left", i.e. the characters between the hyphens.
[Excel_file,PathName] = uigetfile('*.xls', 'Pick a File',...
'C:\Users\User\Documents\Optometry\Year 3\Dissertation\A-scan3');
sheet = 1;
FullXLSfile = [PathName,Excel_file];
[number_data,txt_data,raw_data] = xlsread(FullXLSfile,sheet);
%% data manipulation
NumberOfTitles = length(txt_data);
TextToCompare = txt_data{1};
r1 = 1; % counter for Readings1 vector
r2 = 1; % counter for Readings2 vector
for ff = 1:NumberOfTitles % in your code xlRangeA is a cell vector not a number!
Text = txt_data{ff};
HyphenLocations = find(Text == '-');
Text = Text(HyphenLocations(1,1):HyphenLocations(1,2)); % take only the part that contains the "eye" information
TextToCompare = TextToCompare(HyphenLocations(1,1):HyphenLocations(1,2)); % same here
if (Text == TextToCompare)
Readings1(r1) = number_data(ff); % store the numerical value in a vector
r1 = r1 + 1; % increase the counter of this vector
else
Readings2(r2) = number_data(ff); % same here
r2 = r2 + 1;
end
TextToCompare = txt_data{1}; % TextToCompare re-initialized for the next comparison
end
mean_readings1 = mean(Readings1); % Find the mean of the grouped values
mean_readings2 = mean(Readings2);
I am positive that this can be done in a more efficient and delicate way. I don't know exactly what kind of calculations you want to do so I only included the mean values as an example. Inside the if statement you can also store the txt_data if you need it. Below I have also included a second way which I find more delicate. Just substitute the %%data manipulation part with the part below if you want to test it:
%% more delicate way
Text_Vector = char(txt_data);
TextToCompare2 = txt_data{1};
HyphenLocations2 = find(TextToCompare2 == '-');
TextToCompare2 = TextToCompare2(HyphenLocations2(1,1):HyphenLocations2(1,2));
Text_Vector = Text_Vector(:,HyphenLocations2(1,1):HyphenLocations2(1,2));
Text_Vector = cellstr(Text_Vector);
dummy = strcmpi(Text_Vector,TextToCompare2);
Readings1 = number_data(dummy);
Readings2 = number_data(~dummy);
I hope this helps.
So as the title says, I need to take a user input (e.g. 456) and seperate those numbers so I end up with 4, 5 and 6. The input won't ever be more than 3 digits, however it could be any 3 digits, and it is always going to be numbers. I am very new to Python and coding in general, so my code is sloppy, messy and probably (very) wrong.
The code I have currently is as follows:
`
myint=input
mystr=str(myint)
print(mystr)
mystr[0]
mystr[1]
mystr[2]
int(mystr[0])
int(mystr[1])
int(mystr[2])
globals() mystr[0] = a mystr[1] = b mystr[2] = c
`
This all takes place within my first function
x = raw_input("Please enter a number")
y = [int(x[0]), int(x[1]), int(x[2])]
You can access the different digits using y[0], y[1] and y[2]
create a string from the input like: str(number)
and then iterate through
number = 456
number = str(number)
for i in range(len(number)):
print(number[i])
you should take a look at "strings" "lists" and "arrays" in python and how to handle them. It's pretty basic stuff
You should always remember that a string is an array of chars. That is how Python handles them and you can always call a position of the array.
In order to separate an integer into separate digits, you can use this one-liner:
digits = [int(i) for i in str(original_number)]
This way is more flexible than the accepted answer above, which hard-codes the indexes. Not that it's wrong, but just not as flexible in the case that you have a much larger amount of numbers. At some point, you'll want to do it more programmatically. Hope this helps too!
I have a simple question that I need help on. My code,I believe, is almost complete but im having trouble with the a specific line of code.
I have an assignment question (2 parts) that asks me to find whether a protein (string), has the specified motif (substring) at that particular location (location). This is the first part, and the function and code looks like this:
function output = Motif_Match(motif,protein,location)
%This code wil print a '1' if the motif occurs in the protein starting
at the given location, else it wil print a '0'
for k = 1:location %Iterates through specified location
if protein(1, [k, k+1]) == motif; % if the location matches the protein and motif
output = 1;
else
output = 0;
end
end
This part I was able to get correctly, and example of this is as follows:
p = 'MGNAAAAKKGN'
m = 'GN'
Motif_Match(m,p,2)
ans =
1
The second part of the question, which I am stuck on, is to take the motif and protein and return a vector containing the locations at which the motif occurs in the protein. To do this, I am using calls to my previous code and I am not supposed to use any functions that make this easy such as strfind, find, hist, strcmp etc.
My code for this, so far, is:
function output = Motif_Find(motif,protein)
[r,c] = size(protein)
output = zeros(r,c)
for k = 1:c-1
if Motif_Match(motif,protein,k) == 1;
output(k) = protein(k)
else
output = [];
end
end
I belive something is wrong at line 6 of this code. My thinking on this is that I want the output to give me the locations to me and that this code on this line is incorrect, but I can't seem to think of anything else. An example of what should happen is as follows:
p = 'MGNAAAAKKGN';
m = 'GN';
Motif_Find(m,p)
ans =
2 10
So my question is, how can I get my code to give me the locations? I've been stuck on this for quite a while and can't seem to get anywhere with this. Any help will be greatly appreciated!
Thank you all!
you are very close.
output(k) = protein(k)
should be
output(k) = k
This is because we want just the location K of the match. Using protien(k) will gives us the character at position K in the protein string.
Also the very last thing I would do is only return the nonzero elements. The easiest way is to just use the find command with no arguments besides the vector/matrix
so after your loop just do this
output = find(output); %returns only non zero elements
edit
I just noticed another problem output = []; means set output to an empty array. this isn't what you want i think what you meant was output(k) = 0; this is why you weren't getting the result you expected. But REALLY since you already made the whole array zeros, you don't need that at all. all together, the code should look like this. I also replaced your size with length since your proteins are linear sequences, not 2d matricies
function output = Motif_Find(motif,protein)
protein_len = length(protein)
motif_len = length(motif)
output = zeros(1,protein_len)
%notice here I changed this to motif_length. think of it this way, if the
%length is 4, we don't need to search the last 3,2,or 1 protein groups
for k = 1:protein_len-motif_len + 1
if Motif_Match(motif,protein,k) == 1;
output(k) = k;
%we don't really need these lines, since the array already has zeros
%else
% output(k) = 0;
end
end
%returns only nonzero elements
output = find(output);
tl;dr: My code "works", in that it gives me the answer I need. I just can't get it to stop running when it reaches that answer. I'm stuck with scrolling back through the output.
I'm a complete novice at programming/Python. In order to hone my skills, I decided to see if I could program my own "solver" for Implied Equity Risk Premium from Prof. Damodaran's Valuation class. Essentially, the code takes some inputs and "guesses and tests" a series of interest rates until it gets a "close" value to the input.
Right now my code spits out an output list, and I can scroll back through it to find the answer. It's correct. However, I cannot for the life of me get the code to "stop" at the correct value with the while function.
I have the following code:
per = int(input("Enter the # of periods forecast ->"))
divbb = float(input("Enter the initial dividend + buyback value ->"))
divgr = float(input("Enter the div + buyback growth rate ->"))
tbondr = float(input("Enter the T-Bond rate ->"))+0.000001
sp = int(input("Enter the S&P value->"))
total=0
pv=0
for i in range(1,10000):
erp = float(i/10000)
a = divbb
b = divgr
pv = 0
temppv = 0
print (sp-total, erp)
for i in range(0, per):
a=a * (1+b)
temppv = a / pow((1+erp),i)
pv=pv+temppv
lastterm=(a*1+tbondr)/((erp-tbondr)*pow(1+erp,per))
total=(pv+lastterm)
From his example, with the inputs:
per = 5
divbb = 69.46
divgr = 0.0527
tbondr = 0.0176
sp = 1430
By scrolling back through the output, I can see my code produces the correct minimum at epr=0.0755.
My question is: where do I stick the while to stop this code at that minimum? I've tried a lot of variations, but can't get it. What I'm looking for is, basically:
while (sp-total) > |1|, keep running the code.
per = 5
divbb = 69.46
divgr = 0.0527
tbondr = 0.0176
sp = 1430
total=0
pv=0
i = 1
while(abs(sp-total)) > 1:
erp = i/10000.
a = divbb
b = divgr
pv = 0
temppv = 0
print (sp-total, erp)
for j in range(0, per):
a=a * (1+b)
temppv = a / pow((1+erp),j)
pv=pv+temppv
lastterm=(a*1+tbondr)/((erp-tbondr)*pow(1+erp,per))
total=(pv+lastterm)
i += 1
should work. Obviously, there are a million ways to do this. But the general gist here is that the while loop will stop as soon as it meets the condition. You could also test every time in the for loop and include a break statement, but because you don't know when it will stop, I think a while loop is better in this case.
Let me give you a quick rundown of two different ways you could solve a problem like this:
Using a while loop:
iterator = start value
while condition(iterator):
do some stuff
increment iterator
Using a for loop:
for i in xrange(startvalue, maxvalue):
do some stuff
if condition:
break
Two more thing: if you're doing large ranges, use the generator xrange. Also, it's probably a bad idea to reuse i inside your for loop.
I recommend CS101 from Udacity.com for learning Python. Also, if you're interested in algorithms, work through the problems at projecteuler.com