phrase = input("enter the equation you want diferentiated:")#3x^2+2x^1+-4x^4
new_phrase = phrase.split("+")#splits phrase at the + operator
print(len(new_phrase))
for item in new_phrase:
c = (new_phrase>new_phrase.index("^"))#actul differentiation part c is the power of whatever (this is where python has a problem) line 6
y = (new_phrase<(new_phrase.index("^")-1))# y is the number before x
print(float(c)*float(y)+"^"+float(c)-1)# this is the final differentiated answer
#however it keeps saying ^ is not in the list how can I fix this?
Using Python 3.8.1
The actual main code is starting at for item. This is where the problem occurs, as the input is supposed to be 3x^2+2x^1+-4x^4, or something like, that but Python cannot seem to find where the power to sign "^" in the list thus the rest of the code from the " c =" does not work.
I have created a working version from your code. Mainly the problem was the type inconsistency. Furthermore I have added several comments to the code for the better understanding and it contains several prints for the debugging.
Code:
phrase = input("Enter the equation you want differentiated: ").lower() # 3x^2+2x^1+-4x^4
new_phrase = phrase.split("+") # splits phrase at the + operator
print("Elements: {}".format(new_phrase)) # Print elements of differential
for item in new_phrase:
print("Tested element: {}".format(item))
c = float(item.split("^")[-1]) # Get after part of "^" character
y = float(item.split("^")[0].replace("x", "")) # Get before part of "^" character (withour "x")
print("c={} ; y={}".format(c, y))
print(
"Result: {}^{}".format(float(c) * float(y), float(c) - 1)
) # this is the final differentiated answer
Output:
>>> python3 test.py
Enter the equation you want differentiated: 3x^2+2x^1+-4x^4
Elements: ['3x^2', '2x^1', '-4x^4']
Tested element: 3x^2
c=2.0 ; y=3.0
Result: 6.0^1.0
Tested element: 2x^1
c=1.0 ; y=2.0
Result: 2.0^0.0
Tested element: -4x^4
c=4.0 ; y=-4.0
Result: -16.0^3.0
Here is some Python script that can differentiate algebraic expressions based on your code.
phrase = input("enter the equation you want diferentiated:")#3x^2+2x^1+-4x^4
# Splits phrase at the + operator
split_phrase = phrase.split("+")
# Placeholder for the differentiated phrase
new_phrase = ""
for item in split_phrase:
# Exponent - index of ^ - 1
c = int(item[item.index("^") + 1:])
#Coefficient - from 0 to index of x - 1
y = int(item[0:item.index("x")])
#Reconstructs the algebraic expression
new_phrase += str(c*y) + "x^" + str(c-1)
# Adds a plus sign if it is not the last item
if split_phrase.index(item) != len(split_phrase) - 1:
new_phrase += "+"
Related
First question here.
I am picking up Python and have a question that may be quite basic.
I am trying to create this pattern with a nested loop:
x
x
x
xxx
With the code:
numbers = [1,1,1,3]
for count_x in numbers:
output = ""
for count in range(count_x):
output +=x
print(output)
My question is - why does my output change when I move the position of print(output).
The code above works but when I align print(output) with the for count_x in numbers:, I only get "xxx", when I align print(output) to output +=x, I get the following:
x
x
x
x
xx
xxx
which is very odd because there are only 4 items in the list and it shows me 6 lines of output.
Could someone please help? Really puzzled. Thank yall very much.
There's a difference between these two bits of code (fixing the x/"x" problem along the way - your code won't actually work as is unless you have a variable x):
# First:
numbers = [1,1,1,3]
for count_x in numbers:
output = ""
for count in range(count_x):
output += "x"
print(output)
# Second:
numbers = [1,1,1,3]
for count_x in numbers:
output = ""
for count in range(count_x):
output += "x"
print(output)
In the second, the print is done inside the loop that creates the string, meaning you print it out multiple times while building it. That's where your final three lines come from: *, ** and ***. This doesn't matter for all the previous lines since there's no functional difference. Printing a one character string at the end or after adding each of the one characters has the same effect.
In the first, you only print the string after fully constructing it.
You can see this effect by using a slightly modified version that outputs different things for each outer loop:
numbers = [1,1,1,3]
x = 1
for count_x in numbers:
output = ""
for count in range(count_x):
output += str(x)
print(output)
x += 1
This shows that the final three lines are part of a single string construction (comments added):
1 \
2 >- | Each is one outer/inner loop.
3 /
4 \ | A single outer loop, printing
44 >- | string under construction for
444 / | each inner loop.
In any case, there are better ways to do what you want, such as:
numbers = [1,1,1,3]
for count_x in numbers:
print('x' * count_x)
You could probably also do it on one line with a list comprehension but that's probably overkill.
First I have to receive a string from the user. The function would be capitalizing the introduced string object. It would make the words start with uppercased characters and all remaining characters have lower case. Here is what I did:
ssplit = s.split()
for z in s.split():
if ord(z[0]) < 65 or ord(z[0])>90:
l=(chr(ord(z[0])-32))
new = l + ssplit[1:]
print(new)
else:
print(s)
I can't see what I am doing wrong.
Using str.title() as suggested by #Pyer is nice. If you need to use chr and ord you should get your variables right - see comments in code:
s = "this is a demo text"
ssplit = s.split()
# I dislike magic numbers, simply get them here:
small_a = ord("a") # 97
small_z = ord("z")
cap_a = ord("A") # 65
delta = small_a - cap_a
for z in ssplit : # use ssplit here - you created it explicitly
if small_a <= ord(z[0]) <= small_z:
l = chr(ord(z[0])-delta)
new = l + z[1:] # need z here - not ssplit[1:]
print(new)
else:
print(s)
Output:
This
Is
A
Demo
Text
There are many python methods that could solve this easily for you. For example, the str.title() will capitalize the start of every word in the given string. If you wanted to ensure that all others were lowercase, you could first do str.lower() and then str.title().
s = 'helLO how ARE YoU'
s.lower()
s.capitalize()
# s = 'Hello How Are You'
I'm trying to practice my python so I can improve. I'm kinda stuck and not sure how to proceed. I get an error saying "can only concatenate list(not 'int') to list." I'll leave my code and what I'm trying to do below.
Input a word string (word)
find the string length of word
use range() to iterate through each letter in word (can use to range loops)
Save odd and even letters from the word as lists
odd_letters: starting at index 0,2,...
even_letters: starting at index 1,3,...
print odd and even lists
word = input("Type: ")
word = list(word)
print(word)
odd_letters = []
even_letters = []
length = int(len(word))
for i in range(length):
if i/2 == 0:
even_letters = even_letters + i
elif i/2 != 0:
odd_letters = odd_letters + i
print(even_letters)
print(odd_letters)
I wrote this... Let me know what you think...
word = input("Choose a word to test: ")
word_len = len(word)
print(word," contains ",word_len," letters")
odd_letters = []
even_letters = []
for i in range(1,len(word),2):
even_letters.append(word[i])
for i in range(0,word_len,2):
odd_letters.append(word[i])
print("Odd letters are: ",odd_letters)
print("Even letters are: ",even_letters)
Your code is good, but i decided to find a quicker solution for the program you want. This is my code:
word = str(input("Enter word:"))
store_1 = [x for x in word]
store_2 = []
for idx, val in enumerate(store_1):
store_2.append(idx)
even_numbers = [y for y in store_2 if y%2 == 0]
odd_numbers = [z for z in store_2 if z%2 == 1]
print("List of Even numbers:",even_numbers)
print("List of Odd numbers:",odd_numbers)
The variable 'word' takes in the word from the user. The list 'store_1' uses list comprehension to separate the letters the in the word and store it. Next, i enumerate through 'store_1' and use the variable 'store_2' to only store the indexes of 'store_1'.
Next, I declare another variable 'even_numbers' that uses list comprehension to iterate through 'store_2' and find the even numbers. The next variable 'odd_numbers' also uses list comprehension to find the odd numbers in 'store_2'.
Then, it just prints the even and odd lists to the user. Hope this helps :)
You cannot add an integer to a list, as you have attempted to do here:
even_letters = even_letters + i
You can instead do this (which is now adding a list to a list, which is valid):
even_letters = even_letters + [i]
Or, use append to alter the list in-place, adding the new element to the end:
even_letters.append(i)
Few things:
You cannot "add" an integer directly to a list using '+'. Using append() would be best.
str and str types can be concatenated using '+' so you could change odd_letters and even_letters to str as shown below.
also, by adding 'i' to even and odd, you are adding the iteration variable value.
Since you want the letter to be appended, you need to refer the list index i.e word[i]
and the first letter of what is entered will be at an odd position :)
word = input("Type: ")
word = list(word)
print(word)
odd_letters = ''
even_letters = ''
length = int(len(word))
for i in range(1,length+1):
if i%2 == 0:
even_letters = even_letters + word[i-1]
else:
odd_letters = odd_letters + word[i-1]
print("even_letters",even_letters)
print("odd_letters",odd_letters)
word=input()
word_num=len(word)
print(word_num)
odd_num=[]
even_num=[]
for letters in range(0,word_num,2):
odd_num.append(word[letters])
for letters in range(1,word_num,2):
even_num.append(word[letters])
print(odd_num)
print(even_num)
This is the answer it works with every word, and follows all the requirements.
I'm trying to figure out how to print a one line string while using a for loop. If there are other ways that you know of, I would appreciate the help. Thank you. Also, try edit off my code!
times = int(input("Enter a number: "))
print(times)
a = 0
for i in range(times+1):
print("*"*i)
a += i
print("Total stars: ")
print(a)
print("Equation: ")
for e in range(1,times+1):
print(e)
if e != times:
print("+")
else:
pass
Out:
Enter a number: 5
*
**
***
****
*****
Equation:
1
+
2
+
3
+
4
+
5
How do I make the equation in just one single line like this:
1+2+3+4+5
I don't think you can do a "backspace" after you've printed. At least erasing from the terminal isn't going to be done very easily. But you can build the string before you print it:
times = int(input("Enter a number: "))
print(times)
a = 0
for i in range(times+1):
print("*"*i)
a += i
print("Total stars: ")
print(a)
print("Equation: ")
equation_string = ""
for e in range(1,times+1):
equation_string += str(e)
if e != times:
equation_string += "+"
else:
pass
print(equation_string)
Basically, what happens is you store the temporary equation in equation_str so it's built like this:
1
1+
1+2
1+2+
...
And then you print equation_str once it's completely built. The output of the modified program is this
Enter a number: 5
5
*
**
***
****
*****
Total stars:
15
Equation:
1+2+3+4+5
Feel free to post a comment if anything is unclear.
Instead of your original for loop to print each number, try this:
output = '+'.join([str(i) for i in range(1, times + 1)])
print(output)
Explanation:
[str(i) for i in range(1, times + 1)] is a list comprehension that returns a list of all your numbers, converted to strings so that we can print them.
'+'.join(...) joins each element of your list, with a + in between each element.
Alternatively:
If you want a simple modification to your original code, you can simply suppress the newline from each print statement with the keyword paramater end, and set this to an empty string:
print(e, end='')
(Note that I am addressed the implied question, not the 'how do I do a backspace' question)
Too long for a comment, so I will post here.
The formatting options of python can come into good use, if you have a sequence you wish to format and print.
Consider the following...
>>> num = 5 # number of numbers to generate
>>> n = num-1 # one less used in generating format string
>>> times = [i for i in range(1,num+1)] # generate your numbers
>>> ("{}+"*n + "{}=").format(*times) # format your outputs
'1+2+3+4+5='
So although this doesn't answer your question, you can see that list comprehensions can be brought into play to generate your list of values, which can then be used in the format generation. The format string can also be produced with a l.c. but it gets pretty messy when you want to incorporate string elements like the + and = as shown in the above example.
I think you are looking for the end parameter for the print function - i.e. print(e, end='') which prints each value of e as it arrives followed by no space or newline.
Good afternoon everyone,
I'm trying to sort out names which are already sorted in alphabetical order. I can't figure out why my program isn't working. Any tips or pointers would be nice. Thanks.
def main():
names = ['Ava Fiscer', 'Bob White', 'Chris Rich', 'Danielle Porter', 'Gordon Pike', 'Hannah Beauregard', 'Matt Hoyle', 'Ross Harrison', 'Sasha Ricci', 'Xavier Adams']
input('Please enter the name to be searched: ', )
binarySearch
main()
def binarySearch(names):
first = 0
last = len(names) - 1
position = -1
found = False
while not found and first <= last:
middle = (first + last) / 2
if names[middle] == value:
found = True
position = middle
elif arr[middle] > value:
last = middle -1
else:
first = middle + 1
return position
What does it mean that the program isn't working? Is it a syntax error or is the problem in the wrong results?
With the code you pasted, there are several indentation problems, but besides that, lines:
input('Please enter the name to be searched: ', )
binarySearch
are also syntactically incorrect, the comma is redundant and only the function name appearing just like that is plain wrong. If you are interested in the correctness of your algorithm, it seems alright, but the boundaries can always be tricky. My code below is working and syntactically correct, if you find it helpful. (names are numbers, but that is irrelevant in this case)
names = [1,2,4,5,6,8,9]
def bs(n):
start = 0
end = len(names)
while end - start > 0:
m = (start+end)/2
if names[m] == n:
return m
elif n < names[m]:
end = m
else:
start = m + 1
return -1
print (bs(1))
print (bs(6))
print (bs(9))
print (bs(3))
print (bs(10))
print (bs(-8))
Another thing I would like to point out is that this kind of binary search is already in the python standard library, the bisect module. However, if you are writing your own for practice or for any other reason that is just fine.
if you are using python 3.* then you are going to want to change
m = (start+end)/2
to
m = (start+end)//2
When you do /2 it outputs a float in 3.*