I'm having some trouble here. For my CS assignment, I have to have python take data from a file on my pc and run the data through my program.
So, this code works fine on http://repl.it/languages/Python, but not in python. I'm assuming because my line of code has some Python 2.0 lines of code? I can't seem to fix it. Can you guys help? And, another small question except this one. I have to input some code in my program to take data from a file and run it through my program as I stated above. I have this.
import math
def mean(values):
average = sum(values)*1.0/len(values)
return average
def deviation(values):
length = len(values)
m = mean(values)
total_sum = 0
for i in range(length):
total_sum += (values[i]-m)**2
root = total_sum*1.0/length
return math.sqrt(root)
def median(values):
if len(values)%2 != 0:
return sorted(values)[len(values)/2]
else:
midavg = (sorted(values)[len(values)/2] + sorted(values)[len(values)/2-1])/2.0
return midavg
def main():
x = [15, 17, 40, 16, 9]
print mean(x)
print deviation(x)
print median(x)
main()
How do I specifically have the program take data from the file and run it through my program? The data is just a bunch of numbers, by the way. It's been giving me trouble for some hours now. Thanks if you can help out.
This is what I know about the opening/closing file stuff so far
f = open("filename.txt")
data = f.readlines()
f.close()
Apparently you are using python2.x:
I'm assuming because my line of code has some Python 2.0 lines of code?
So yes, you do have a problem: In python3.x, print became a function.
Thus, your prints need to be changed:
print mean(x)
print deviation(x)
print median(x)
Becomes
print(mean(x))
print(deviation(x))
print(median(x))
Also, your part about opening and closing files is unclear.
Related
I would like to import one python file into another and then compile the main file. How can I do this?
MWE: Suppose I would like to calculate factorial of a positive integer. It can be done successfully by the following way:
n=5
fact = 1
if n < 0:
print("Sorry, factorial does not exist for negative numbers")
elif n == 0:
print("The factorial of 0 is 1")
else:
for i in range(1,n + 1):
fact = fact*i
print "%d!=%d"%(n,fact)
But I would like to create a secondary file say "auxfile.py" containing:
fact = 1
if n < 0:
print("Sorry, factorial does not exist for negative numbers")
elif n == 0:
print("The factorial of 0 is 1")
else:
for i in range(1,n + 1):
fact = fact*i
print "%d!=%d"%(n,fact)
And another main file say "main.py" containing:
print "Required factorial is given below:"
for n in range(30):
import auxfile.py
How can I do this?
Note: I know defining a function the whole process can be done in a single file. But I have to do a large program where I would like to apply this process.
Simple, just use the import method. To make your life easier simply copy the .py file you would like to import to the same folder that the file you want to import the other code file into is in.
E.g if you wanted to import happy.py to sad.py simply do:
import happy
This would give the following traceback (look at example below):
Hello
Although, this will instantly run everything outside of any def loops in the .py file. Therefore, if you wanted to run a single def loop in the file, then use the following code:
Example contents of happy.py:
print("Hello")
def okay():
print("okay")
If you did:
happy.okay()
This would give you the following traceback:
Hello
okay
TIP FOR YOUR CODE IN MAIN.PY:
You did:
print "Required factorial is given below:"
whereas you forgot the brackets. You should use: print("Required factorial is given below:") This will avoid future errors!
Hope this helps!
you can do it like this:
auxfile.py
def factorial(n):
fact = 1
if n < 0:
print("Sorry, factorial does not exist for negative numbers")
elif n == 0:
print("The factorial of 0 is 1")
else:
for i in range(1,n + 1):
fact = fact*i
print "%d!=%d"%(n,fact)
in your main.py :
from auxfile import factorial
print "Required factorial is given below:"
for n in range(30):
factorial(n)
If you're trying to avoid using a function--maybe you could wrap your entire code in the for loop? If it is not as simple as a for-loop, maybe you could copy your main code into the other file above it.
For example:
Before:
file1: "Your main code that wants to call the code below"
file2: "Your code that is too cumbersome to convert to a function"
After:
file1:
"Your main code that wants to call the code below"
for n in range(30):
"Your code that is too cumbersome to convert to a function"
There's still quite an ugly solution, which is to use the exec built-in function.
First of all, you read the code from your file:
with open("auxiliary.py", 'r') as f:
content = f.readlines()
Then you filter out the lines you don't want, so that content is a string containing your Python code, that is:
# The following evaluates to True
content == 'fact = 1\nif n < 0:\n print("Sorry, factorial does not exist for negative numbers")\nelif n == 0:\n print("The factorial of 0 is 1")\nelse:\n for i in range(1,n + 1):\n fact = fact*i\n print "%d!=%d"%(n,fact)'
Then you can just call the exec function, which will act as if the lines were included in lieu of the call of the function:
exec content # Or exec(content), both seems to work in Python 2.7
See here for a further explanation.
Note that you will have access to fact and every other variables, just as if you had written these lines in your main file.
Be aware that this might get dangerous: if you don't formally identify which lines to execute (like, put a comment as an identifier, or if the auxiliary file never changes), you may end up running some code from your auxiliary file you dont want to.
I'm having some trouble with my code in python. I just started learning input and output in class, and how to have python read in data from text files(barely. I'm still a huge beginner). Anyways, my assignment is that I have to have my program read in data from a file and run it through my program. Problem is, I don't have a good idea on how to do that and was wondering if you guys could help me out. The text file just contains a huge life of numbers for python to use in my program. My program finds the mean, median, and standard deviation of a list of numbers that are given to it. Now, instead of user input data, my professor wants python to use data from a file that was already pre-written.
My code:
import math
def mean(values):
average = sum(values)*1.0/len(values)
return average
def deviation(values):
length = len(values)
m = mean(values)
total_sum = 0
for i in range(length):
total_sum += (values[i]-m)**2
root = total_sum*1.0/length
return math.sqrt(root)
def median(values):
if len(values)%2 != 0:
return sorted(values)[len(values)//2]
else:
midavg = (sorted(values)[len(values)//2] + sorted(values)[len(values)//2-1])//2.0
return midavg
def main():
x = [15, 17, 40, 16, 9]
print (mean(x))
print (deviation(x))
print (median(x))
main()
Now, I have to edit my code so it opens the file, takes the data, and reads the data through my equations. Only problem is, I don't have a good idea on how to do that. Could anyone please help?
I've tried basic input and output myself, but it's done no justice in helping me with the bigger picture.
def main():
total=0
input = open('Stats.txt')
for nextline in input:
mylist = nextline.split()
for n in mylist:
total+=int(n)
print(total)
You have to fill your list from the file.
Open the file and iterate over the lines. Convert the content of the line to an integer and append it to your list. If you don't cxonvert the data you'll get strings and those won't work with mathematical operations. Close your file.
Now work with your list.
filename = 'newfile.txt'
data = []
source = open(filename)
for line in source:
data.append(int(line))
source.close()
print(mean(data))
print(deviation(data))
# more stuff with data
There is a way to let Python close the file for you so you won't have to remember it.
with open(filename) as source:
for line in source:
data.append(int(line))
According to your edit this might not be what you want. If the numbers are in one line, rather than one number per line, you'll have to take a different approach (split).
what i want to do is write a code that has a file (in the code, no need to be input by user), and the code picks a random line from the file - whatever it is, a long line, an ip or even a word and at the end of the loop puts it into a string so i could use that in other parts of the code.
i tried using randomchoice(lines) but wasn't sure how to continue from here.
after that i tried using:
import random
def random_line(afile):
line = next(afile)
for num, aline in enumerate(afile):
if random.randrange(num + 2): continue
line = aline
return line
which also for some reason didnt work for me.
The last method you posted worked for me. Maybe you are not opening the file correctly. Here is another approach, using random.choice
import random
def random_line(f):
return random.choice([line for line in f])
f = open("sample.txt", 'r')
print random_line(f)
Edit:
Another way would be (thanks to #zhangxaochen):
def random_line(f):
return random.choice(f.readlines())
Translating another answer of mine from C:
def random_line(afile):
count = 0
kept_line = None
for line in afile:
if random.randint(0, count) == 0:
kept_line = line
count += 1
return kept_line
Edit: This appears to do the same thing as random.choice. I wonder if they use the same algorithm?
Edit 2: from the comments and a little experimentation it appears random.choice uses a different algorithm, which will be much more efficient if all of the elements are already in memory. This isn't usually the case for files unless you use readlines. There will be a tradeoff between having to keep the entire file in memory vs. having to calculate n random numbers.
I have attached a python 2.7 script to answer question number 2 from the following link: http://labs.spotify.com/puzzles/
My attempt to solve is currently being met with a "wrong answer" reply, yet my code successfully works for the sample inputs on the site. I have tried modifying it to return and even print a list of the top m songs, instead of printing them out individually, but that did not work either. Any help or ideas would be great. Thanks in advance
import sys
def main():
line1 = sys.stdin.readline().split()
total_songs = int(line1[0])-1
num_songs_return = int(line1[1])
data = sys.stdin.read().split()
while(total_songs >= 0):
data[2*total_songs]= float(data[2*total_songs]) * (total_songs+1)
total_songs-=1
answers = [(data[a], data[a+1]) for a in range(0,len(data),2)]
answers.sort(reverse=True)
for n in range(num_songs_return):
print answers[n][1]
main()
I just want to only print my reslut to Spss cell called "vysledek", in python script.
Ivot only two arrays, so i comper this arrays and count only in how many cases is the second one bigger than firts one, and wants to print the reslut to vysledek.
Begin program.
import spss, spssaux
spssaux.OpenDataFile('C:\Users\šoťa\Desktop\datacssd.sav')
dlist = ['PARLAMENTCSSD2010']
ilist = ['KRAJCSSD2012']
vlist = ['VYSLEDKY']
ddim = Len(dlist)
idim = Len(ilist)
For i In range(ddim):
If dlist[x] < ilist[x]:
Print ('the ilist is higher in cases: + '.')
spss.Submit(r"""
vlist[1]=vlist[1]+1
End program.
Not sure exactly how the SPSS interface works but I suspect it's not working because nearly every line in your code is invalid Python syntax. Try converting to the the following:
import spss, spssaux
spssaux.OpenDataFile('C:\Users\šoťa\Desktop\datacssd.sav')
dlist = ['PARLAMENTCSSD2010']
ilist = ['KRAJCSSD2012']
vlist = ['VYSLEDKY']
ddim = len(dlist)
idim = len(ilist)
for i in range(ddim):
if dlist[x] < ilist[x]:
print ('the ilist is higher in cases: + .')
spss.Submit("vlist[1]=vlist[1]+1")
I suspect that some capitalization-crazy tool broke the original post, but the problem remains the use of the Submit api. The argument to Submit is one or more lines of SPSS syntax, not what is shown above. If you accumulate the count within the Python code (and not in the character string vlist), you can just print it as an ordinary Python print statement.
If you want to turn this into a nice pivot table, you can use the
spss.SimplePivotTable api.