after learning a lot about python I moved to solve some programming problem. I am ok with writing normal scripts but when it comes to programing problems I ruined. After trying some problem and getting runtime-error I thought there would be a problem with code but soon I started Google and found there is problem with input that how it is taken. I searched and view some question on stackoverflow but that doesn't help. Now taking about a particular problem I am trying to solve the below problem.
You are given an array A of size N, and Q queries to deal with. For each query, you are given an integer X, and you're supposed to find out if X is present in the array A or not.
Input:
The first line contains two integers, N and Q, denoting the size of array A and number of queries. The second line contains N space separated integers, denoting the array of elements Ai. The next Q lines contain a single integer X per line.
Output:
For each query, print YES if the X is in the array, otherwise print NO.
Sample input
5 6
50 40 30 20 10
10
20
30
40
50
100
Sample Output
YES
YES
YES
YES
YES
NO
(this is neither my homework nor I am getting reward) this is the solution i tried.
import sys
p=[]
A=[]
file_name=sys.argv[1]
f= open(file_name)
user_args= f.read()
user_input=user_args.split()
N,n=int(user_input[0]), int(user_input[1])
for i in range(2,N+2):
A.append(int(user_input[i]))
for i in range(N+2,n+N+2):
p.append(int(user_input[i]))
for i in range(0,int(n)):
linearsearch(A, p[i])
sys.exit()
#and then writing the linearsearch(A,p) for checkign the element.
that I tried and got compilation-log ok with runtime-error. Everything is ok if i run this code on my machine but when i submit it then this runtime error. I also searched for this error but no idea why am I getting this?
Here some user are suggesting the solution. what I want is feedback on code I have already written and as I tried in this to read the input from a file via command line.Where am I mistaking? Am I lacking some basics?
Your problem is that you are supposed to read from stdin, not from a file - this will not work:
file_name=sys.argv[1]
f= open(file_name)
The skeleton of the solution should be something like this:
n, q = raw_input().split()
a = raw_input().split()
for query in sys.stdin:
query.strip()
if test_if_query_in(a):
print "YES"
else:
print "NO"
Have fun writing test_if_query_in. The solution is very easy in Python because there is a builtin collection type with O(1) search.
You should use raw_input for reading data.
For example my solution is:
N,Q = map(int, raw_input().split(' '))
arr = map(int, raw_input().split(' '))
arr = set(arr)
for i in xrange(Q):
N = int(raw_input())
if N in arr:
print("YES")
else:
print("NO")
I'm quite new to the for loops in Python. So, I want to write a program that asks the user to enter to enter 20 different scores and then I want the program to calculate the total and display it on the screen. How could I use a for loop to do this?
edit: I can ask the user to for the different numbers but I don't know how to then add them.
Without giving you the full code here is the pseudocode for what your code should look like
x = ask user for input
loop up till x //Or you could hard code 20 instead of x
add user input to a list
end
total = sum values in list
print total
Here are all the things you need to implement the logic
User input/output:
http://anh.cs.luc.edu/python/hands-on/3.1/handsonHtml/io.html
Loops:
https://wiki.python.org/moin/ForLoop
Summing a list:
https://docs.python.org/2/library/functions.html
Try something like this:
total = 0; # create the variable
for i in range(1,20): # iterate over values 1 to 20 as a list
total += int(input('Please enter number {0}: '.format(i)));
print("Sum of the numbers is '{0}'".format(total))
I'd suggest you go through the tutorials on the python site:
Python 3 is here https://docs.python.org/3/tutorial/index.html
Python 2 is here https://docs.python.org/2/tutorial/index.html
I could go into a lot of detail here and explain everything, however I'd only be duplicating the resources already available. Written far better than I could write them. It would be far more beneficial for you (and anyone else reading this who has a similar issue) to go through these tutorials and get familiar with the python documentation. These will give you a good foundation in the basics, and show you what the language is capable of.
Input
To read a value from the commandline you can use the input function, e.g. valueString = input("prompt text"). Notice the value stored is of type string, which is effectively an array of ASCI/Unicode characters.
So in order to perform math on the input, you first need to convert it to its numerical value - number = int(valueString) does this. So you can now add numbers together.
Adding numbers
Say you had two numbers, num1 and num2, you can just use the addition operator. For example num3 = num1 + num2. Now suppose you have a for loop and want to add a new number each time the loop executes, you can use the total += newNum operator.
total = 0
for _ in range(1,20):
num = input('> ')
total += int(num)
print(total)
I hope this helps.
It prints diga and digb but doesnt work with c! Any help? It's supposed to be a Denary to Binary converter but only 1-64, once i've cracked the code will increase this! Thanks so much
denaryno=int(input("Write a number from 1-64 "))
if 64%denaryno > 0:
diga=0
remaindera=(64%denaryno)
if 32/denaryno<1:
digb=1
remainderb=(denaryno%32)
else:
digb =0
if 16/remainderb<1:
digc=1
remainderc=(denaryno%16)
else:
digc=0
if 8/remainderc<1:
digd=1
remainderd=(denaryno%8)
else:
digd=0
if 4/remainderd<1:
dige=1
remaindere=(denary%4)
else:
dige=0
if 2/remaindere<1:
digf=1
remainderf=(denary%2)
else:
digf=0
if 1/remainderf<1:
digg=1
remainderg=(denary%1)
else:
digg=0
print (str(diga)+str(digb))
You only set digc in one of the top if/else statement. If 32/denaryno<1 is True, you don't set digc at all.
Set digc at the top of the function (to 0 or whatever else you want it to be). This applies to all the digit variables, digd, dige, etc.
What you really should do, instead, is use a list of digits, and append either a 0 or a 1 to that list every time you divide the number by a factor.
You may want to take a look at the divmod() function; it returns both the quotient and the remainder. You could also do with some looping here to slash the number of if statements needed here:
number = int(input("Write a number from 1-64 "))
digits = []
factor = 64
while number:
quotient, number = divmod(number, factor)
digits.append(quotient)
factor //= 2
print(''.join(map(str, digits)))
Wow that was a lot of work, you don't have to do all that.
def bin_convert(x, count=8):
return "".join(map(lambda y:str((x>>y)&1), range(count-1, -1, -1)))
here are the functions comprising this one from easy->important
str() returns a string
range() is a way to get a list from 1 number to another. Written like this range(count-1, -1, -1) counts backwards.
"".join() is a way to take an iterable and put the pieces together.
map() is a way to take a function and apply it to an iterable.
lambda is a way to write a function in 1 line. I was being lazy and could have written another def func_name(y) and it would have worked just as well.
>> is a way to shift bits. (which I believe understanding this one is the key component to understanding your problem)
I'm trying to solve problem 13 from Euler project, and I'm trying to make the solution beautiful (at least, not ugly). Only "ugly thing" I do is that I'm pre-formating the input and keep it in the solution file (due to some technical reasons, and 'cause I want to concentrate on numeric part of problem)
The problem is "Work out the first ten digits of the sum of the following one-hundred 50-digit numbers."
I wrote some code, that should work, as far as I know, but it gives wrong result. I've checked input several times, it seems to be OK...
nums=[37107287533902102798797998220837590246510135740250,
46376937677490009712648124896970078050417018260538,
74324986199524741059474233309513058123726617309629,
91942213363574161572522430563301811072406154908250,
23067588207539346171171980310421047513778063246676,
89261670696623633820136378418383684178734361726757,
28112879812849979408065481931592621691275889832738,
44274228917432520321923589422876796487670272189318,
47451445736001306439091167216856844588711603153276,
70386486105843025439939619828917593665686757934951,
62176457141856560629502157223196586755079324193331,
64906352462741904929101432445813822663347944758178,
92575867718337217661963751590579239728245598838407,
58203565325359399008402633568948830189458628227828,
80181199384826282014278194139940567587151170094390,
35398664372827112653829987240784473053190104293586,
86515506006295864861532075273371959191420517255829,
71693888707715466499115593487603532921714970056938,
54370070576826684624621495650076471787294438377604,
53282654108756828443191190634694037855217779295145,
36123272525000296071075082563815656710885258350721,
45876576172410976447339110607218265236877223636045,
17423706905851860660448207621209813287860733969412,
81142660418086830619328460811191061556940512689692,
51934325451728388641918047049293215058642563049483,
62467221648435076201727918039944693004732956340691,
15732444386908125794514089057706229429197107928209,
55037687525678773091862540744969844508330393682126,
18336384825330154686196124348767681297534375946515,
80386287592878490201521685554828717201219257766954,
78182833757993103614740356856449095527097864797581,
16726320100436897842553539920931837441497806860984,
48403098129077791799088218795327364475675590848030,
87086987551392711854517078544161852424320693150332,
59959406895756536782107074926966537676326235447210,
69793950679652694742597709739166693763042633987085,
41052684708299085211399427365734116182760315001271,
65378607361501080857009149939512557028198746004375,
35829035317434717326932123578154982629742552737307,
94953759765105305946966067683156574377167401875275,
88902802571733229619176668713819931811048770190271,
25267680276078003013678680992525463401061632866526,
36270218540497705585629946580636237993140746255962,
24074486908231174977792365466257246923322810917141,
91430288197103288597806669760892938638285025333403,
34413065578016127815921815005561868836468420090470,
23053081172816430487623791969842487255036638784583,
11487696932154902810424020138335124462181441773470,
63783299490636259666498587618221225225512486764533,
67720186971698544312419572409913959008952310058822,
95548255300263520781532296796249481641953868218774,
76085327132285723110424803456124867697064507995236,
37774242535411291684276865538926205024910326572967,
23701913275725675285653248258265463092207058596522,
29798860272258331913126375147341994889534765745501,
18495701454879288984856827726077713721403798879715,
38298203783031473527721580348144513491373226651381,
34829543829199918180278916522431027392251122869539,
40957953066405232632538044100059654939159879593635,
29746152185502371307642255121183693803580388584903,
41698116222072977186158236678424689157993532961922,
62467957194401269043877107275048102390895523597457,
23189706772547915061505504953922979530901129967519,
86188088225875314529584099251203829009407770775672,
11306739708304724483816533873502340845647058077308,
82959174767140363198008187129011875491310547126581,
97623331044818386269515456334926366572897563400500,
42846280183517070527831839425882145521227251250327,
55121603546981200581762165212827652751691296897789,
32238195734329339946437501907836945765883352399886,
75506164965184775180738168837861091527357929701337,
62177842752192623401942399639168044983993173312731,
32924185707147349566916674687634660915035914677504,
99518671430235219628894890102423325116913619626622,
73267460800591547471830798392868535206946944540724,
76841822524674417161514036427982273348055556214818,
97142617910342598647204516893989422179826088076852,
87783646182799346313767754307809363333018982642090,
10848802521674670883215120185883543223812876952786,
71329612474782464538636993009049310363619763878039,
62184073572399794223406235393808339651327408011116,
66627891981488087797941876876144230030984490851411,
60661826293682836764744779239180335110989069790714,
85786944089552990653640447425576083659976645795096,
66024396409905389607120198219976047599490197230297,
64913982680032973156037120041377903785566085089252,
16730939319872750275468906903707539413042652315011,
94809377245048795150954100921645863754710598436791,
78639167021187492431995700641917969777599028300699,
15368713711936614952811305876380278410754449733078,
40789923115535562561142322423255033685442488917353,
44889911501440648020369068063960672322193204149535,
41503128880339536053299340368006977710650566631954,
81234880673210146739058568557934581403627822703280,
82616570773948327592232845941706525094512325230608,
22918802058777319719839450180888072429661980811197,
77158542502016545090413245809786882778948721859617,
72107838435069186155435662884062257473692284509516,
20849603980134001723930671666823555245252804609722,
53503534226472524250874054075591789781264330331690]
result_sum = []
tmp_sum = 0
for j in xrange(50):
for i in xrange(100):
tmp_sum += nums[i] % 10
nums[i] =nums[i] / 10
result_sum.insert(0,int(tmp_sum % 10))
tmp_sum = tmp_sum / 10
for i in xrange(10):
print result_sum[i]
Your code works by adding all the numbers in nums like a person would: adding column by column. Your code does not work because when you are summing the far left column, you treat it like every other column. Whenever people get to the far left, they write down the entire sum. So this line
result_sum.insert(0,int(tmp_sum % 10))
doesn't work for the far left column; you need to insert something else into result_sum in that case. I would post the code, but 1) I'm sure you don't need it, and 2) it's agains the Project-Euler tag rules. If you would like, I can email it to you, but I'm sure that won't be necessary.
You could save the numbers in a file (with a number on each line), and read from it:
nums = []
with open('numbers.txt', 'r') as f:
for num in f:
nums.append(int(num))
# nums is now populated with all of the numbers, so do your actual algorithm
Also, it looks like you want to store the sum as an array of digits. The cool thing about Python is that it automatically handles large integers. Here is a quote from the docs:
Plain integers (also just called integers) are implemented using long in C, which gives them at least 32 bits of precision (sys.maxint is always set to the maximum plain integer value for the current platform, the minimum value is -sys.maxint - 1). Long integers have unlimited precision.
So using an array of digits isn't really necessary if you are working with Python. In C, it is another story...
Also, regarding your code, you need to factor in the digits in tmp_sum, which contains your carry-over digits. You can add them into result_sum like this:
while tmp_sum:
result_sum.insert(0,int(tmp_sum % 10))
tmp_sum /= 10
This will fix your issue. Here, it works.
Since you already have all the numbers in a list, you should be able to take the sum of them pretty easily. Then you just need to take the first ten digits of the sum. I won't put any code here, though.
As Simple as this :
Values.txt will contain all digits.
nums = []
with open("values.txt",'r') as f:
for num in f:
nums.append(int(num))
print(str(sum(nums))[:10])
Just as easy is storing it in csv and using pandas:
def foo():
import pandas as pd
table = pd.read_csv("data.txt", header = None, usecols = [0])
and then iterate through panda dataframe:
sum = 0
for x in range(len(table)):
sum += int(table[0][x])
return str(sum)[:10]
just keep in mind that Python handles the large digits for you.
Here is the question proposed by the text.
Write an improved version of the Chaos program from Chapter 1 that allows a user to input two initial values and the number of iterations and then prints a nicely formatted table showing how the values change over time. for example, if the starting values were .25 and .26 with 10 iterations, the table would look like so:
following this is a table with a index 0.25 0.26 as headers and then the 10 iterations in two columns.
here is my initial Chaos program.
# File: chaos.py
def main ():
print ("This program illustrates a chaotic function")
x=eval (input("enter a number between 0 and 1: "))
for i in range (10):
x = 3.9 * x * (1-x)
print (x)
main()
my question is how do i change it to fulfil the above question..
Please if answering take in mind this is my first programming class ever.
You really just have to duplicate the functionality you already have. Instead of just asking the user for an x value, also ask for a y value.
x= float(input("enter a number between 0 and 1: "))
y= float(input("enter another number between 0 and 1: "))
Then in your loop you need to do the same thing you did with the x value to the y value. When you print, remember that you can print two values (x and y) at once by separating them with a comma.
Also, as PiotrLegnica said, you should use float(input(...)) instead of eval(input(...)). Since you know that the user should enter a floating point number (between 0 and 1) you don't have to call eval. Calling eval could be dangerous as it will execute any instruction given to it. That might not matter right now, but it's better to not get in the habit of using it.