how do i print the index of a value with letters in a string in python?

Question

I have:

*MONTHS = ("January", "February", "March", ... "December") (all months included)

I'm supposed to input the 3 letter abbreviation for a month and get the index value for the month. So far, I have:

for M in MONTHS:
    shortMonths = M[0:3]
    print shortMonths

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

I noticed that the output months in shortMonths do not have quotation marks, which is making it impossible to test if an abbreviation is in shortMonths:

MMM = "Feb"

print list(shortMonths).index(MMM) + 1 # taking into consideration that the first month of the list, January, is month 0+1 = 1 and so on for all months

ValueError: 'Feb' is not in list

How can I fix this without creating a function? Also, this is an assignment question. And, we're not allowed to use dictionaries or maps or datetime

Try print 'hi' in your interpreter and the Mystery of the Missing Quotation Marks may become solved. — roippi
– roippi, Commented Oct 17, 2013 at 6:03
This is not a real Python question... more about programming in general (i.e. what 'print' means!). I suggest to start learning how to debug your program so that you will be able to find mistakes and learn from them. — Don
– Don, Commented Oct 17, 2013 at 8:39
@roippi, the Mystery of the Missing Quotation Marks is cool :) — JadedTuna
– JadedTuna, Commented Oct 17, 2013 at 9:30

Gabe · Accepted Answer · 2013-10-17 06:02:01Z

2

It sounds like you want shortMonths to be a list, but you're just assigning a string to it.

I think you want something like this:

shortMonths = [] # create an empty list
for M in MONTHS:
    shortMonths.append(M[0:3]) # add new entry to the list
print shortMonths # print out the list we just created

Or using a list comprehension:

# create a list containing the first 3 letters of each month name
shortMonths = [M[0:3] for M in MONTHS]
print shortMonths # print out the list we just created

answered Oct 17, 2013 at 6:02

Gabe

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1 Comment

sberry Over a year ago

Points out the OP's misunderstanding. Gives a pointer to list comp. +1 from me.

Jitu · Accepted Answer · 2013-10-17 06:11:44Z

0

shortMonths is string not a list. Do as below.

shortMonths = []
  for M in MONTHS:
    shortmonths.append(M[0:3])

answered Oct 17, 2013 at 6:11

Jitu

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Comments

dansalmo · Accepted Answer · 2013-10-17 08:00:55Z

0

>>> months = ["January", "Febuary", "March", "April"]
>>> search = "Mar"
>>> [i for i, mo in enumerate(months) if search == mo[0:3]][0]
2
>>> search = "Fan"
>>> [i for i, mo in enumerate(months) if search == mo[0:3]][0]
IndexError: list index out of range

answered Oct 17, 2013 at 8:00

dansalmo

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Comments

JadedTuna · Accepted Answer · 2013-10-17 09:16:42Z

It's easy:

>>> months = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December']
>>> search = "Jan"
>>> months.index([i for i in months if i[:3].lower() == search.lower()][0])+1
1
>>> # Or
... def getmonth(search):
...    for i in months:
...        if i[:3].lower() == search.lower():
...            return x.index(i)+1
>>> getmonth("Feb")
2

To catch the error:

months = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December']
while True:
    search = ""
    while len(search) != 3:
        search = raw_input("Enter first 3 letters of a month: ")[:3]
    month = [i for i in months if i[:3].lower() == search.lower()]
    if not month: # Not in the list, empty list: []
        print "%s is not a valid abbreviation!"%search
        continue
    print months.index(month[0])+1

user278064 · Accepted Answer · 2013-10-17 09:41:13Z

0

abbr = raw_input("Enter the month abbr:")


months = ['January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December']
months_abbr = [month.lower()[:3] for month in months]
index = months_abbr.index(abbr.lower())
if index >= 0:
    print "abbr {0} found at index {1}".format(abbr, index)
else:
    print "abbr {0} not found".format(abbr)

answered Oct 17, 2013 at 9:41

user278064

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