I'm trying to write a function that returns the first even number in a list, using a while loop
def first_even(list):
while i%2 !=0: #I'm not sure if this is a good start for the while loop, but I think I'm supposed to use something%2...
#no idea what to do here
A good and very short coding style will be:
for i in list:
if i%2 == 0:
return i
Related
I'm writing a program to check if a given user input is a palindrome or not. if it is the program should print "Yes", if not "no". I realize that this program is entirely too complex since I actually only needed to check the whole word using the reversed() function, but I ended up making it quite complex by splitting the word into two lists and then checking the lists against each other.
Despite that, I'm not clear why the last conditional isn't returning the expected "Yes" when I pass it "racecar" as an input. When I print the lists in line 23 and 24, I get two lists that are identical, but then when I compare them in the conditional, I always get "No" meaning they are not equal to each other. can anyone explain why this is? I've tried to convert the lists to strings but no luck.
def odd_or_even(a): # function for determining if odd or even
if len(a) % 2 == 0:
return True
else:
return False
the_string = input("How about a word?\n")
x = int(len(the_string))
odd_or_even(the_string) # find out if the word has an odd or an even number of characters
if odd_or_even(the_string) == True: # if even
for i in range(x):
first_half = the_string[0:int((x/2))] #create a list with part 1
second_half = the_string[(x-(int((x/2)))):x] #create a list with part 2
else: #if odd
for i in range(x):
first_half = the_string[:(int((x-1)/2))] #create a list with part 1 without the middle index
second_half = the_string[int(int(x-1)/2)+1:] #create a list with part 2 without the middle index
print(list(reversed(second_half)))
print(list(first_half))
if first_half == reversed(second_half): ##### NOT WORKING BUT DONT KNOW WHY #####
print("Yes")
else:
print("No")
Despite your comments first_half and second_half are substrings of your input, not lists. When you print them out, you're converting them to lists, but in the comparison, you do not convert first_half or reversed(second_half). Thus you are comparing a string to an iterator (returned by reversed), which will always be false.
So a basic fix is to do the conversion for the if, just like you did when printing the lists out:
if list(first_half) == list(reversed(second_half)):
A better fix might be to compare as strings, by making one of the slices use a step of -1, so you don't need to use reversed. Try second_half = the_string[-1:x//2:-1] (or similar, you probably need to tweak either the even or odd case by one). Or you could use the "alien smiley" slice to reverse the string after you slice it out of the input: second_half = second_half[::-1].
There are a few other oddities in your code, like your for i in range(x) loop that overwrites all of its results except the last one. Just use x - 1 in the slicing code and you don't need that loop at all. You're also calling int a lot more often than you need to (if you used // instead of /, you could get rid of literally all of the int calls).
Iam using break statement but it doesn't bring out of loop ,
I tried to find prime factors of given number but due to malfunctioning of break i cant do it
def fact(x):
for i in range(2,x+1):
if x%i==0:
xx.append(i)
x=x//i
if x==1:
break
else:
print('fact')
fact(x)
a=12
xx=[]
fact(a)
print(xx)
The main issue is that you are "double counting" factors.
having identified a factor, add it and call recursively with the number that results after removing the factor.
At the moment, you do that, but then also look for the next factor in the current function call.
There are of course little ways to improve this some more like skipping over values of i that we know cannot be factors of n and making the function return the array of results itself rather than updating a global, but this will get you going:
With the lightest modification to your existing code what you want to do is:
def fact(x):
for i in range(2,x+1):
if x%i == 0:
xx.append(i)
fact(x//i)
return
xx=[]
fact(12)
print(xx)
This will show you:
[2, 2, 3]
I am programming a program that will make a list of all numbers from 1 to 200 that:
are not divisible by 7 or 11
do not contain the digit 7 or 11 in their number.
I want to use the pass function so when the condition is not met, it will continue with the next number. I don't really know how to do it. The pass function is probably the wrong one. I know the break function does also not work because it will end the whole loop.
Please explain me how to make this program work on this way. There are probably plenty other ways to calculate this, but the point is that i want to understand how to use the for loops better :).
n = 200 #all digits till and including 200
numbers = [] #empty list for accumulation values
for i in range(1,(n+1)):
if i%7 == 0 or i%11 == 0: #if one of these 3 conditions are met
pass #it should continue to the next number (i)
if str(7) in str(i):
pass
if str(11) in str(i):
pass
numbers.append(i)
print(numbers)
print(sum(numbers)) # for my assignment i need to sum the list
use continue in place of pass.
pass does nothing
continue skips to the next loop
so i had to use continue in my example.
Complete beginner here making my first program with PyAutoGui as I cannot get access to the software's API. My issues are currently being that I am unable to come up with a solution to name each subclip with a different appended letter on the end. The naming convention should go like so, MI899001~AA, MI899001~AB, MI899001~AC, MI899001~AD. The only thing that changes is the last letter.
Below is the relevant code I'm currently using for the program I am writing;
def naming_promo():
x = string.ascii_uppercase
pyautogui.typewrite('DNH~P336007A' + x[0][0])
for i in range(7):
if i == 0:
sub_clip_clean()
else:
if i >= 1:
pyautogui.typewrite('567890qwe', 0.2)
sub_clip_package()
naming_promo() # See above Fn for method
pyautogui.moveTo(646, 404, duration=0.50)
pyautogui.click()
move_clips()
The naming_promo() takes the ascii_uppercase and types the first letter. I however can't figure out how to iterate through each character in the string as the For Loop repeats. I've googled many solutions, but I guess I can't get my head around how to do a loop in a loop and increment the x value used each time.
This is my first post so apologies for any etiquette I break. Any help and explanation would be greatly appreciated.
This is my first answer so apologies for any etiquette I break.
I'm not sure I understand everything here, since there's a few functions in the code that I don't know about. However, are you just looking for something like:
def naming_promo(n):
x = string.ascii_uppercase
pyautogui.typewrite('DNH~P336007A' + x[0][n])
and further down in your code, simply create a variable and increment it up one after use:
m = 0
for i in range(7):
if i == 0:
sub_clip_clean()
else:
if i >= 1:
pyautogui.typewrite('567890qwe', 0.2)
sub_clip_package()
naming_promo(m) # See above Fn for method
m += 1
pyautogui.moveTo(646, 404, duration=0.50)
pyautogui.click()
move_clips()
Hello friend while learning python it came into my mind that is there any way by which we can directly jump to a particular value of iterator without iterating fro example
a=range(1.10) or (1,2,3,4,5,6,7,8,9)
for i in a
print ("value of i:",i)
if (certain condition)
#this condition will make iterator to directly jump on certain value of
#loop here say if currently i=2 and after this it will directly jump the
#the iteration value of i=8 bypassing the iterations from 3 to 7 and
#saving the cycles of CPU)
There is a solution, however it involves complicating your code somewhat.
It does not require an if function however it does require both while and try loops.
If you wish to change the numbers skipped then you simply change the for _ in range() statement.
This is the code:
a = [1,2,3,4,5,6,7,8,9,10]
at = iter(a)
while True:
try:
a_next = next(at)
print(a_next)
if a_next == 3:
for _ in range(4, 8):
a_next = next(at)
a_next = str(a_next)
print(a_next)
except StopIteration:
break
The iterator interface is based on the next method. Multiple next calls are necessary to advance in the iteration for more that one element. There is no shortcut.
If you iterate over sequences only, you may abandon the interator and write an old-fashioned C-like code that allows you to move the index:
a = [1,2,3,4,5,6,7,8,9,10]
a_len = len(a)
i = 0
while i < a_len:
print(a[i])
if i == 2:
i = 8
continue
i += 1