This is from Ken Lambert's "Fundamentals of Python":
{
sum=0
while True:
data = input('enter a number or just enter to quit: ')
if data == "":
break
number = float(data)
sum += number
print("the sum is", sum)
}
error message:
data = input('enter a number or just enter to quit: ')
File "<string>", line 0
^
SyntaxError: unexpected EOF while parsing
Process finished with exit code 1
Use raw_input rather than input. The description of input begins with:
Equivalent to eval(raw_input(prompt))
You're getting an error because eval("") reports a syntax error, because there's no expression there; it gets EOF immediately.
On the other hand, the description of raw_input says:
The function then reads a line from input, converts it to a string (stripping a trailing newline), and returns that.
Since you want the string that the user typed, rather than the evaluation of an expression, this is the function you should use.
The error you provided is because you used input, which tries to execute the text from stdin as python code https://docs.python.org/2/library/functions.html#input. I've provided some fixes below.
sum=0
while True:
data = raw_input('enter a number or just enter to quit: ')
if len(data) < 1:
break
number = float(data)
sum += number
print("the sum is %f" % sum)
I found that you have a syntax problem with your code. If you want to to put data in a variable you should use that:
variable = raw_input("Please enter ____")
Therefore you should replace line 4 to:
data = raw_input('enter a number or just enter to quit: ')
Related
Hello Fellow Developer's and Eng's:
How can I handle these two type's of input 1) when user enter "-0" and 2) When user enter minus symbol "-", within my while loop for adding nonnegative integers.
The program developed functions in the overall design, which is to add non negative integers, but it has a flaw when a user input -0 or -(minus) sign. I want to print('you have entered a negative int or a negative/minus - symbol') when these entries are made by the user.
Currently, the program continues without adding when user submit -0 in the input and there is ValueError when user just submit - symbol.
Please provide feedback.
entry = 0
sum = 0
# Request input from the user
print('This is nonnegative integer addition program. \n',)
while entry >= 0:
entry=int(input('Please enter numbers to add: '))
if entry >=0:
sum+=entry
elif entry<0 or str(entry[0])=='-' or str(entry)=='-0': # -0 nor (first index -(minus) does not work
print('You have entered a negative integer or symbol:', \
entry, ', therefore you have been exited out of the program')
print('total integer input sum =',sum)
As mentioned in the other answer. You convert your value to an int and you can no longer access the characters. I've made the program store the user_input and check that.
entry = 0
sum = 0
# Request input from the user
print('This is nonnegative integer addition program. \n',)
while entry >= 0:
user_input = input('Please enter numbers to add: ')
if '-' in user_input:
print(
'You have entered a negative integer or symbol:',
user_input,
', therefore you have been exited out of the program'
)
break
entry = int(user_input)
sum+=entry
print('total integer input sum =',sum)
In this version I store the input string as user_input and check it for a '-' symbol. I use '-' in instead of user_input[0]=='-' because input that starts with a space can still work with int.
Another thing to note, your if/elif was over specified.
if entry >=0:
sum+=entry
elif entry<0 or str(entry[0])=='-' or str(entry)=='-0':
break
In your second clause entry is guaranteed to be less than zero. So the str(entry[0]) never gets called. Thankfully because it was an error. Your if statement is equivalent to.
if entry>=0:
...
else:
...
Lastly a small point. When you have a set of brackets like in your print statment. You don't need a \ to indicate a line continuation.
print(
"one",
"two"
)
Python recognizes the open (. If you wanted to continue a string you would need it.
print("one \
two")
When you are storing the input as int entry=int(input('Please enter numbers to add: ')) the entry value is 0 because on int the is no -0 so if you want to check if the user input -0 you need to keep it as str.
You can try
entry = 0
sum = 0
print('This is nonnegative integer addition program. \n',)
while int(entry) >= 0:
entry=input('Please enter numbers to add: ')
if entry[0] !='-':
if int(entry) >= 0:
sum+=int(entry)
elif entry[0]=='-' or entry=='-0':
print('You have entered a negative integer or symbol:', \
entry, ', therefore you have been exited out of the program')
entry = -1
print('total integer input sum =',sum)
I'm trying to create a program that takes input from the user, -1 or 1 to play or quit, number of characters (n), two words for comparison (s1,s2), and calls this function: def strNcompare (s1,s2,n) and then prints the result. The function should return 0,-1,1 if n-character portion of s1 is equal to, less than, or greater than the corresponding n-character of s2, respectively. So for example is the first string is equal to the second string, it should return a 0.
The loop should end when the user enters, -1.
I'm just starting out in Python so the code I have is pretty rough. I know I need an if/else statement to print the results using the return value of the function and a while loop to make the program run.
This is what I have so far, it by no means works but my knowledge ends here. I don't know how to integrate the character (n) piece at all either.
com = input ("String comparison [1(play), -1(quit)]: ")
while (com=='1'):
s1 = input ("enter first string: ")
s2 = input ("enter second string: ")
n = int(input("number of characters: ")
s1 = s1[:n]
s1 = s2[:n]
if com==-1:
break
def strNcompare(s1,s2,n):
return s1==s2
elif s1==s2:
print(f'{s1} is equal to {s2}')
elif s1>s2:
print (f'{s1} is greater than {s2}')
elif s1<s2:
print (f'{s1} is less than {s2}')
else:
print ("QUIT")
break
com = input ("String comparison [1(play), -1(quit)]: ")
As of 10/05/2019 - I revised the code and now I am getting a syntax error at "s1 = s1[:n]"
it did not made much sense and especially the variable 'n' is not completely clear to me. I would not code it like that but I tried to be as close to your logic as possible.
com = input ("String comparison [1(play), -1(quit)]: ")
while (com=='1'):
s1 = input ("enter first string: ")
s2 = input ("enter second string: ")
n = input ("number of characters: ") #what is the purpose of this?
if s1==s2:
print(f'{s1} is equal than {s2}')
elif s1>s2:
print (f'{s1} is greater than {s2}')
elif s1<s2:
print (f'{s1} is less than {s2}')
else:
print ("Error")
Question:
The hand is displayed.
The user may input a word or a single period (the string ".")
to indicate they're done playing
Invalid words are rejected, and a message is displayed asking
the user to choose another word until they enter a valid word or "."
When a valid word is entered, it uses up letters from the hand.
After every valid word: the score for that word is displayed,
the remaining letters in the hand are displayed, and the user
is asked to input another word.
The sum of the word scores is displayed when the hand finishes.
The hand finishes when there are no more unused letters or the user inputs a "."
hand: dictionary (string -> int)
wordList: list of lowercase strings
I am trying to write a code for my Python programming online course. However, I am getting an error :
ERROR: Failed to display hand correctly - be sure 'Current Hand' and the display of the hand are on the same line!
Here is my code :
def playHand(hand, wordList, n):
total = 0
while True:
print("\nCurrent Hand:",)
displayHand(hand)
entered = input('Enter word, or a "." to indicate that you are finished: ')
if entered == '.':
print ("Goodbye! Total score: " + str(total) +" points.")
break
if isValidWord(entered, hand, wordList) == False:
print ("Invalid word, please try again.")
else:
total += getWordScore(entered, n)
print (str(entered), "earned", getWordScore(entered,n), "points. Total:", str(total))
hand = updateHand(hand, entered)
if calculateHandlen(hand) == 0:
print ("\nRun out of letters. Total score: " + str(total) +" points.")
break
The answer is in your code already:
def displayHand(hand):
for letter in hand.keys():
for j in range(hand[letter]):
print(letter,end=" ") # print all on the same line
print() # print an empty line
Use end=" " in your print statement!!
New to programming. How to count and print iterations(attempts) I had on guessing the random number?` Let's say, I guessed the number from 3-rd attempt.
import random
from time import sleep
str = ("Guess the number between 1 to 100")
print(str.center(80))
sleep(2)
number = random.randint(0, 100)
user_input = []
while user_input != number:
while True:
try:
user_input = int(input("\nEnter a number: "))
if user_input > 100:
print("You exceeded the input parameter, but anyways,")
elif user_input < 0:
print("You exceeded the input parameter, but anyways,")
break
except ValueError:
print("Not valid")
if number > user_input:
print("The number is greater that that you entered ")
elif number < user_input:
print("The number is smaller than that you entered ")
else:
print("Congratulation. You made it!")
There are two questions being asked. First, how do you count the number of iterations? A simple way to do that is by creating a counter variable that increments (increases by 1) every time the while loop runs. Second, how do you print that number? Python has a number of ways to construct strings. One easy way is to simply add two strings together (i.e. concatenate them).
Here's an example:
counter = 0
while your_condition_here:
counter += 1 # Same as counter = counter + 1
### Your code here ###
print('Number of iterations: ' + str(counter))
The value printed will be the number of times the while loop ran. However, you will have to explicitly convert anything that isn't already a string into a string for the concatenation to work.
You can also use formatted strings to construct your print message, which frees you from having to do the conversion to string explicitly, and may help with readability as well. Here is an example:
print('The while loop ran {} times'.format(counter))
Calling the format function on a string allows you replace each instance of {} within the string with an argument.
Edit: Changed to reassignment operator
Two programs seperated by -------------------------------------------------------------------------------------------
The program above the line is called program1
The program below the line is called program2
The only differens between the programs are int(input()) in program1 and input in program2
PS: I dont know what its called but in the text where I wrote "okd" (okayed) maybe I should write true?
The question/my line of thought:
In program1 if number: will be "okd" when number == integer and number != 0
In program2 if number: will be "okd" when number == string and number != 0
Does if number: check if number is what its trying to be in Try:
For example in program1 its trying to be an integer and in program2 its trying to be a string and in either program if number is what it tried to be it will be "okd" and the programs will return number and break?
def limit(question):
while True:
try:
number = int(input(question))
except:
number = 0
if number:
return number
break
question = "type an integer expressed with digits and press enter: "
number = limit(question)
print(number)
def limit(question):
while True:
try:
number = input(question)
except:
number = 0
if number:
return number
break
question = "type an integer expressed with digits and press enter: "
number = limit(question)
print(number)
The body of the if statement will NOT be evaluated if the expression given to it is False, 0, None, '', [], etc. The if statement will not try to detect if number is trying to be a string/int.
So if the user enters 0, then number = int(input(question)) will run just fine, but number will be zero, so the body of the if statement will not be evaluated.
The purpose of the try/except is to check if the statements in the try body will run in to errors. So if a user enters some numbers, then number = int(input(question)) will run without any problems. If a user enters something that is not an integer, then number = int(input(question)) will give you a ValueError, and the except block will catch the error and be evaluated.