I can't seem to figure out why there is a parsing error on "else:" in this python code. Please help.
I am trying to count the number of times the same 'email' appeared using dictionary from the text "mbox-short.txt". The final result should print the key (that is the email) and the value (number of times repeated).
name = raw_input("Enter file:")
if len(name) < 1 : name = "mbox-short.txt"
try:
handle = open(name)
except:
print 'Invalid input.'
quit()
def emailrepeat(s):
d = dict()
if s not in d:
d[s] = 1
else:
try:
d[s] = d[s] + 1
except:
print "error"
return d
for line in handle:
if line.startswith('From:') == True:
continue
if line.startswith('From') == True:
newline = line.split()
email = newline[1]
print email
print emailrepeat(email)
Thanks everyone!
What the **else** mean?
If your want note the else statement, please use the # or '''.
remove the asterisk around else, to make else a comment use #, """, or '''
asterisk will result in error
What I want to check for is if the user input is an empty string. I want the code to execute and output: "No input", however whenever I enter no input it goes to the next if statement and executes that with a blank value.
import urllib
import re
myString = " "
i = 0
def getStockPrice():
text_file = open("data.txt", "w")
url = "http://finance.yahoo.com/q?s=" + symbolslist
htmlfile = urllib.urlopen(url)
htmltext = htmlfile.read()
regex = '<span id="yfs_l84_' + symbolslist+ '">(.+?)</span>'
pattern = re.compile(regex)
price = re.findall(pattern,htmltext)
if str(price) == myString:
print "No input"
else:
print "the price of", symbolslist," is ", price
text_file.write(str(price))
text_file.close()
dino = raw_input("What stock would you like to Check?: ")
symbolslist = dino
getStockPrice()
while i < 1000:
lilly = raw_input("What other stocks do you want to check?: ")
symbolslist = lilly
getStockPrice()
"Empty string is the one which len(String) == 0. In your case len(MyString) == 1"_wanderlust2
This gave me some insight on the issue, it was very amateurish for me to make this mistake. Thanks!
In Python, an empty string evaluates to False. That means that you can use a simple code to improve your if statement:
user_input = raw_input("Stock to check")
user_input = user_input.strip() # be sure to clear any whitespace!
if user_input:
# continue on with your program
...
If you use this Python idiom, your code will be more concise and easier to read. If you get used to it, you'll understand other Python programs that use the feature too.
For your code, I would refactor what you have to something like this:
while True:
user_input = raw_input("Stock to check")
user_input = user_input.strip() # be sure to clear any whitespace!
if user_input:
if user_input.lower() == 'quit':
break
getStockPrice(user_input)
That would rely on you changing your getStockPrice function to accept an argument though! That's a simple change. Try adding an extra word within your parentheses:
def getStockPrice(symbolslist):
I am fairly new to python and I need to make a program to ask 10 questions, save the score into a file and allow someone to read the scores in from the file.
My problem: I need to check if the person who has done the quiz already has a record in the file, and if so, I need to add their score to the end of their record.
The records should look like this:
name,score,score,score,score,
etc so they can be split using commas.
I am also looking for the simplest answer, not the most efficient. Also, if you could comment the code, it would make it much easier. Here is my code so far:
import random
import math
import operator as op
import sys
import re
def test():
num1 = random.randint(1, 10)
num2 = random.randint(1, num1)
ops = {
'+': op.add,
'-': op.sub,
'*': op.mul,
}
keys = list(ops.keys())
rand_key = random.choice(keys)
operation = ops[rand_key]
correct_result = operation(num1, num2)
print ("What is {} {} {}?".format(num1, rand_key, num2))
while True:
try:
user_answer = int(input("Your answer: "))
except ValueError:
print("Only enter numbers!")
continue
else:
break
if user_answer != correct_result:
print ("Incorrect. The right answer is {}".format(correct_result))
return False
else:
print("Correct!")
return True
print("1. Are you a student?")
print("2. Are you a teacher?")
print("3. Exit")
while True:
try:
status = int(input("Please select an option:"))
except ValueError:
print("Please enter a number!")
else:
if status not in {1,2,3}:
print("Please enter a number in {1,2,3}!")
else:
break
if status == 1:
username=input("What is your name?")
while not re.match("^[A-Za-z ]*$", username) or username=="":
username=input(str("Please enter a valid name (it must not contain numbers or symbols)."))
print ("Hi {}! Wellcome to the Arithmetic quiz...".format(username))
while True:
try:
users_class = int(input("Which class are you in? (1,2 or 3)"))
except ValueError:
print("Please enter a number!")
else:
if users_class not in {1,2,3}:
print("Please enter a number in {1,2,3}!")
else:
break
correct_answers = 0
num_questions = 10
for i in range(num_questions):
if test():
correct_answers +=1
print("{}: You got {}/{} {} correct.".format(username, correct_answers, num_questions,
'question' if (correct_answers==1) else 'questions'))
if users_class == 1:
class1 = open("Class1.txt", "a+")
newRecord = username+ "," + str(correct_answers) + "," + "\n"
class1.write(newRecord)
class1.close()
elif users_class == 2:
class2 = open("Class2.txt", "a+")
newRecord = username+ "," + str(correct_answers) + "," + "\n"
class2.write(newRecord)
class2.close()
elif users_class == 3:
class3 = open("Class3.txt", "a+")
newRecord = username+ "," + str(correct_answers) + "," + "\n"
class3.write(newRecord)
class3.close()
else:
print("Sorry, we can not save your data as the class you entered is not valid.")
EDIT:
Add this function before your "test" function:
def writeUserScore(file, name, score):
with open (file, "r") as myfile:
s = myfile.read()
rows = s.split("\n")
data = {}
for row in rows:
tmp = row.split(",")
if len(tmp) >= 2: data[tmp[0]] = tmp[1:]
if name not in data:
data[name] = []
data[name].append(str(score))
output = ""
for name in data:
output = output + name + "," + ",".join(data[name]) + "\n"
handle = open(file, "w+")
handle.write(output)
handle.close()
After that, where you have "if users_class == 1:" do this:
writeUserScore("Class1.txt", username, str(correct_answers))
Do the same for the other two else ifs.
Let me know what you think!
Try using a dictionary to hold the existing file data.
Read the file in a variable called "str" for example. And then do something like this:
rows = str.split("\n")
data1 = {}
for row in rows:
tmp = row.split(",")
data1[tmp[0]] = tmp[1:]
When you have a new score you should then do:
if username not in data1:
data1[username] = []
data1[username] = str(correct_answers)
And to save the data back to the file:
output = ""
for name in data1:
output = outupt + name + "," + ",".join(data1[name]) | "\n"
And save the contents of "output" to the file.
PS: If you are not bound by the file format you can use a JSON file. I can tell you more about this if you wish.
Hope that helps,
Alex
First, define these functions:
from collections import defaultdict
def read_scores(users_class):
"""
If the score file for users_class does not exist, return an empty
defaultdict(list). If the score file does exist, read it in and return
it as a defaultdict(list). The keys of the dict are the user names,
and the values are lists of ints (the scores for each user)
"""
assert 0 <= users_class <= 3
result = defaultdict(list)
try:
lines =open("Class%d.txt"%users_class,'r').readlines()
except IOError:
return result
for line in lines:
# this line requires python3
user, *scores = line.strip().split(',')
# if you need to use python2, replace the above line
# with these two lines:
# line = line.strip().split(',')
# user, scores = line[0], line[1:]
result[user] = [int(s) for s in scores]
return result
def write_scores(users_class, all_scores):
"""
Write user scores to the appropriate file.
users_class is the class number, all scores is a dict kind of dict
returned by read_scores.
"""
f = open("Class%d.txt"%users_class,'w')
for user, scores in all_scores.items():
f.write("%s,%s\n"%(user, ','.join([str(s) for s in scores])))
def update_user_score(users_class, user_name, new_score):
"""
Update the appropriate score file for users_class.
Append new_score to user_name's existing scores. If the user has
no scores, a new record is created for them.
"""
scores = read_scores(users_class)
scores[user_name].append(new_score)
write_scores(users_class, scores)
Now, in the last portion of your code (where you actually write the scores out) becomes much simpler. Here's an example of writing some scores:
update_user_score(1, 'phil', 7)
update_user_score(1, 'phil', 6)
update_user_score(1, 'alice', 6)
update_user_score(1, 'phil', 9)
there will be two lines in Class1.txt:
phil,7,6,9
alice,6
We read the whole file into a dict (actually a defaultdict(list)),
and overwrite that same file with an updated dict. By using defaultdict(list), we don't have to worry about distinguishing between updating and adding a record.
Note also that we don't need separate if/elif cases to read/write the files. "Scores%d.txt"%users_class gives us the name of the file.
How do I make it where if the user enters 'no' the program won't go through the for loop either. I don't want it to tmpfile.write(line) if the user enters 'no'.
def remove():
coname = raw_input('What company do you want to remove? ') # company name
f = open('codilist.txt')
tmpfile = open('codilist.tmp', 'w')
for line in f:
if coname.upper() in line:
while True:
answer = raw_input('Are you sure you want to remove ' + line.upper() + '?')
if answer == 'yes':
print line.upper() + '...has been removed.'
elif answer == 'no':
break # HERE IS WHERE I NEED HELP
else:
print 'Please choose yes or no.'
else:
tmpfile.write(line)
else:
print 'Company name is not listed.'
f.close()
tmpfile.close()
os.rename('codilist.tmp', 'codilist.txt')
Set a flag variable and then break out of the while loop. Then in the for loop, check if the flag is set, and then break.
PS: if is not a loop
The easiest way to do this is to create a function that gets user input:
def get_yes_or_no(message):
while True:
user_in = raw_input(message).lower()
if user_in in ("yes", "no"):
return user_in
And modify your original function like so:
def remove():
coname = raw_input('What company do you want to remove? ') # company name
f = open('codilist.txt')
tmpfile = open('codilist.tmp', 'w')
for line in f:
if coname.upper() in line:
answer = get_yes_or_no('Are you sure you want to remove ' + line.upper() + '?')
#answer logic goes here
else:
tmpfile.write(line)
else:
print 'Company name is not listed.'
f.close()
tmpfile.close()
os.rename('codilist.tmp', 'codilist.txt')
Python has exceptions, which you can use in place of a GOTO type of construction.
class Breakout(Exception):
pass
def remove():
coname = raw_input('What company do you want to remove? ') # company name
f = open('codilist.txt')
tmpfile = open('codilist.tmp', 'w')
try:
for line in f:
if coname.upper() in line:
while True:
answer = raw_input('Are you sure you want to remove ' + line.upper() + '?')
if answer == 'yes':
print line.upper() + '...has been removed.'
elif answer == 'no':
raise Breakout()
else:
print 'Please choose yes or no.'
else:
tmpfile.write(line)
else:
print 'Company name is not listed.'
except Breakout:
pass
f.close()
tmpfile.close()
os.rename('codilist.tmp', 'codilist.txt')
Notice where in exception is raised in the middle there.
You have to put the whole for loop in a function and use return to get out of it:
def find_and_remove(f,coname,tmpfile):
for line in f:
if coname.upper() in line:
while True:
answer = raw_input('Are you sure you want to remove ' + line.upper() + '?')
if answer == 'yes':
print line.upper() + '...has been removed.'
elif answer == 'no':
return # HERE IS WHERE I NEED HELP
else:
print 'Please choose yes or no.'
else:
tmpfile.write(line)
else:
print 'Company name is not listed.'
def remove():
coname = raw_input('What company do you want to remove? ') # company name
f = open('codilist.txt')
tmpfile = open('codilist.tmp', 'w')
find_and_remove(f,coname,tmpfile)
f.close()
tmpfile.close()
os.rename('codilist.tmp', 'codilist.txt')
Instead of using an infinite loop and breaking when you skip a line, differentiate between the three cases (skip, remove, and invalid answer) using a flag in the loop condition. You set the flag to exit the loop in the skip case, break in the remove case, and leave the flag as-is in the invalid answer case. This lets you use the else clause of the while (which is triggered if the while exits because the condition became false) to detect the skip case. From there, you can jump ahead to the next iteration of the for loop using continue (or skip all the rest of the lines using break - it isn't quite clear from the question which you intend, but the difference is change of keyword):
for line in f:
if coname.upper() in line:
answered = False
while not answered:
answer = raw_input('Are you sure you want to remove ' + line.upper() + '?')
if answer == 'yes':
print line.upper() + '...has been removed.'
break
elif answer == 'no':
answered = True # HERE IS WHERE I NEED HELP
else:
print 'Please choose yes or no.'
else:
continue
else:
tmpfile.write(line)
else:
print 'Company name is not listed.'
fileName = raw_input("Enter the filename: ")
n = input("Enter the line you want to look: ")
f = open(fileName,'r')
numbers = []
for line in f:
sentenceInLine = line.split('\n')
for word in sentenceInLine:
if word != '':
numbers.append(word)
print numbers
print len(numbers)
print numbers[n-1]
if n == 0:
print "There is no 0 line"
break
i think you missed to split sentenceInLine like sentenceInLine.split(' ')
You are looping over each line, then you split lines based on '\n'. That \n is a line break character. That would confuse your logic right there.
So it is a bit confusing what you are trying to do but you should check n after the user has inputed a value for n. not at the end.
You may want to also catch the exception where file cannot be found I think this is what you need:
fileName = raw_input("Enter the filename: ")
n = input("Enter the line you want to look: ")
if n == 0:
print "There is no 0 line"
sys.exit();
try:
f = open(fileName,'r')
except IOError:
print "Could not find file"
sys.exit()