How do I take a string of numbers in Python 2.7.2 and make each number its own element in a list?

Question

I have a string of numbers. I would like to take each number and insert it into a list where each number is its own element in the list so I can use a For loop to search for that number. In the code below I have written an example:

string = "3, 4, 5, 99"

a_list = []

a_list.append(string)

for i in range (0, len(a_list)):
    if int(a_list[i]) == 99:
        print "yes 99 is in here"

I would like the loop to print "yes 99 is in here" because it is. I think the problem with my code is that entire string is listed as element 0 (the only element) in the list. Please help!! I know this is basic, but I'm having trouble finding the solution online. I'm new to programming.

Answer 1

You need to parse the string to separate each number as it's own element. Luckily Python has your back with that.

>>> a_list= string.split(", ")
>>> a_list
['3', '4', '5', '99']

Answer 2

l = map(int, s.split(','))
if 99 in l:
    print "yes 99 is in here"

We are splitting your list at the comma and then mapping this to an integer type. Otherwise you'd have a list filled with strings.

After the first line, your list looks like this:

[3, 4, 5, 99]

Your check then is as simple as seeing if 99 is in your list ( l )

Answer 3

Try

string_list = [float(i) for i in string.split(', ')]

if 99 in string_list:
    print '99 is here'

The string split method creates a list of the individual numbers but they are strings. So the [float(i) for i in string.split(', ')] part converts them all to floats. You can use int(i) if you know they will be integers or you want to interpret them as such.

Answer 4

remove spaces at the beginning and end (if present) using str.strip .

then split the string with ',' as delimiter using str.split which returns a list of strings.

Convert each element in list to int

string = "3, 4, 5, 99"

strings = string.strip().split(",")

a_list = [int(i) for i in strings]

for i in range (0, len(a_list)):
    if int(a_list[i]) == 99:
        print "yes 99 is in here"

Answer 5

Why not instead:

if string == "99" or\
   string.startswith("99,") or\
   string.endswith(", 99") or\
   ", 99," in string: print "Hooray!"