Python newbie here. I am writing a program to count how many times a substring is a string, but keep receiving the error message: TypeError: a is undefined. I have looked at /googled similar threads but the code is usually convoluted and hard to follow.
Here is my code:
def stringcount(char, word):
for eachChar in word:
if char==eachChar:
count=count+1
return count
print count
stringcount('a', 'apple')
Thanks a lot!
def stringcount(c, word):
count = 0
for eachChar in word:
if c==eachChar:
count=count+1
return count
>>> stringcount('a', 'apple')
1
>>>
But in this case you can simply use:
>>> 'apple'.count('a')
1
This code is dangerous. You aren't initializing count, so if count exists as a variable in the namespace you could get a different result every time. For example, if you call the function multiple times, count will not reset and the second time the function is called it will return 2. The following code is much safer and works.
def stringcount(char, word):
count = 0
for eachChar in word:
if char==eachChar:
count += 1
return count
>>> stringcount('a', 'apple')
1
Also note that you can simply do 'apple'.count('a') to do the same thing.
A nice one-liner does the same thing:
def stringcount(char, word):
return sum(x==char for x in word)
>>> stringcount('p', 'apple')
2
If you aren't writing this for a programming exercise, you could do:
def stringcount(c, word):
return word.count(c)
print stringcount("a", "apple")
Docs: http://docs.python.org/library/string.html#string.count
'apple'.count('a').string.count(). Anyway, some people may be more comfortable with functional syntax than object oriented syntax. Never mind Zen 12 :)
counton string, e.g. 'apple'.count('a')countbefore assigning it a value, so you'll getUnboundLocalError.