I'm playing with both learning python and trying to get github issues into a readable form. Using the advice on How can I convert JSON to CSV? I came up with this:
import json
import csv
f=open('issues.json')
data = json.load(f)
f.close()
f=open("issues.csv","wb+")
csv_file=csv.writer(f)
csv_file.writerow(["gravatar_id","position","number","votes","created_at","comments","body","title","updated_at","html_url","user","labels","state"])
for item in data:
csv_file.writerow([item["gravatar_id"], item["position"], item["number"], item["votes"], item["created_at"], item["comments"], item["body"], item["title"], item["updated_at"], item["html_url"], item["user"], item["labels"], item["state"]])
Where "issues.json" is the json file containing my github issues. When I try to run that, I get
File "foo.py", line 14, in <module>
csv_file.writerow([item["gravatar_id"], item["position"], item["number"], item["votes"], item["created_at"], item["comments"], item["body"], item["title"], item["updated_at"], item["html_url"], item["user"], item["labels"], item["state"]])
TypeError: string indices must be integers
What am I missing here? Which are the "string indices"? I'm sure that once I get this working I'll have more issues, but for now , I'd just love for this to work!
When I tweak the for
statement to simply
for item in data:
print item
what I get is ... "issues" -- so I'm doing something more basic wrong. Here's a bit of my json:
{"issues":[{"gravatar_id":"44230311a3dcd684b6c5f81bf2ec9f60","position":2.0,"number":263,"votes":0,"created_at":"2010/09/17 16:06:50 -0700","comments":11,"body":"Add missing paging (Older>>) links...
when I print data
it looks like it is getting munged really oddly:
{u'issues': [{u'body': u'Add missing paging (Older>>) lin...
As a rule of thumb, when I receive this error in Python I compare the function signature with the function execution.
For example:
def print_files(file_list, parent_id):
for file in file_list:
print(title: %s, id: %s' % (file['title'], file['id']
So if I'll call this function with parameters placed in the wrong order and pass the list as the 2nd argument and a string as the 1st argument:
print_files(parent_id, list_of_files) # <----- Accidentally switching arguments location
The function will try to iterate over the parent_id
string instead of file_list
and it will expect to see the index as an integer pointing to the specific character in string and not an index which is a string (title
or id
).
This will lead to the TypeError: string indices must be integers
error.
Due to its dynamic nature (as opposed to languages like Java, C# or Typescript), Python will not inform you about this syntax error.
I had a similar issue with Pandas, you need to use the iterrows() function to iterate through a Pandas dataset Pandas documentation for iterrows
data = pd.read_csv('foo.csv')
for index,item in data.iterrows():
print('{} {}'.format(item["gravatar_id"], item["position"]))
note that you need to handle the index in the dataset that is also returned by the function.
str[a:b]
tl;dr: use a colon :
instead of a comma in between the two indices a
and b
in str[a:b]
When working with strings and slice notation (a common sequence operation), it can happen that a TypeError
is raised, pointing out that the indices must be integers, even if they obviously are.
>>> my_string = "hello world"
>>> my_string[0,5]
TypeError: string indices must be integers
We obviously passed two integers for the indices to the slice notation, right? So what is the problem here?
This error can be very frustrating - especially at the beginning of learning Python - because the error message is a little bit misleading.
We implicitly passed a tuple of two integers (0 and 5) to the slice notation when we called my_string[0,5]
because 0,5
(even without the parentheses) evaluates to the same tuple as (0,5)
would do.
A comma ,
is actually enough for Python to evaluate something as a tuple:
>>> my_variable = 0,
>>> type(my_variable)
<class 'tuple'>
So what we did there, this time explicitly:
>>> my_string = "hello world"
>>> my_tuple = 0, 5
>>> my_string[my_tuple]
TypeError: string indices must be integers
Now, at least, the error message makes sense.
We need to replace the comma ,
with a colon :
to separate the two integers correctly:
>>> my_string = "hello world"
>>> my_string[0:5]
'hello'
A clearer and more helpful error message could have been something like:
TypeError: string indices must be integers (not tuple)
A good error message shows the user directly what they did wrong and it would have been more obvious how to solve the problem.
[So the next time when you find yourself responsible for writing an error description message, think of this example and add the reason or other useful information to error message to let you and maybe other people understand what went wrong.]
:
to separate its indices (and step range, e.g. str[from:to:step]
),
(e.g. t = 1,
)Cheers and happy programming
winklerrr
[I know this question was already answered and this wasn't exactly the question the thread starter asked, but I came here because of the above problem which leads to the same error message. At least it took me quite some time to find that little typo.
So I hope that this will help someone else who stumbled upon the same error and saves them some time finding that tiny mistake.]
This can happen if a comma is missing. I ran into it when I had a list of two-tuples, each of which consisted of a string in the first position, and a list in the second. I erroneously omitted the comma after the first component of a tuple in one case, and the interpreter thought I was trying to index the first component.
data
is a dict
object. So, iterate over it like this:
for key, value in data.iteritems():
print key, value
for key, value in data.items():
print(key, value)
The variable item
is a string. An index looks like this:
>>> mystring = 'helloworld'
>>> print mystring[0]
'h'
The above example uses the 0
index of the string to refer to the first character.
Strings can't have string indices (like dictionaries can). So this won't work:
>>> mystring = 'helloworld'
>>> print mystring['stringindex']
TypeError: string indices must be integers
Source: Stackoverflow.com