I'm very new to python and am having trouble with the following bit of code. The aim is to create a function that prints all the integers within a string.
def get_digits(str1):
for i in str1:
if i.isdigit():
return i
However it is only returning the first integer in the string, and I am unsure on how to get it to print all of them.
My apologies if the question is stupid, I have looked around for a while on this site and others and haven't been able to work it out.
Condensed down into a list comprehension
def get_digits(strval):
return [i for i in strval if i.isdigit()]
print get_digits('432jfsd5fs')
print ''.join(get_digits('432jfsd5fs'))
Returns
['4', '3', '2', '5']
4325
>>> def print_digits(str1):
... for i in str1:
... if i.isdigit():
... print i
...
>>> print_digits("a12b3")
1
2
3
print prints things. return sends the answer back to whatever ran the function. i guess you are confusing the two because if you run a function within python it prints whatever is returned. but that is only because python is trying to be helpful and show you the result; it's not how you normally print things.
if you really want return the digits, and print them elsewhere, then one way to do it is build a list of results:
>>> def get_digits(str1):
... results = []
... for i in str1:
... if i.isdigit():
... results.append(i)
... return results
...
>>> print(get_digits("a12b3"))
['1', '2', '3']
Whenever you return from a function, the function stops executing. I would recommend a generator here, which allows you to return an iterable from a function without writing much code.
This question smacks of homework, so I'm not going to give the full answer, but I would recommend looking at this StackOverflow answer for a great explanation of generators and the yield keyword.
You can loop through the digits and return a list of them, like this:
def get_digits(str1):
digits = [] # define new list
for i in str1:
if i.isdigit():
digitis.append(i) # i is a digit, append to list
return digits # return the list of digits
Your function quits after it finds the first digit. In order for it to return all the digits, collect the results in a list.
def get_digits(str1):
digits = []
for i in str1:
if i.isdigit():
digits.append(i)
return digits
You can also simplify your function, by using a list comprehension:
def get_digits(str1):
return [d for d in str1 if d.isdigit()]
If you just want to print the results and not return them, replace return i with print i in your original function.
def get_digits(str1):
numbers = ""
for i in str1:
if i.isdigit():
numbers = numbers + i
return numbers
Simple explanation:
# your code
def get_digits(str1):
for i in str1:
if i.isdigit():
return i
when a function meets return i, it stops its further execution, and return the value.
Since others has explained in detail, I'll just put more solutions for reference:
#1. Using generator
def get_digits_generator(str1):
for i in str1:
if i.isdigit():
yield i
#2. Returning a list of digits
def get_digits_list(str1):
list_of_digits = []
for i in str1:
if i.isdigit():
list_of_digits.append(i)
return list_of_digits
#3. List comprehension
str1 = "asdbh12njasdo29ns"
list_of_digits = [character for character in str1 if character.isdigit()]
a=""
def get_digits(str1):
for i in str1:
if i.isdigit():
a=a&i
return a
try it like this. Because you return while you find the first digital.
