Output first 100 characters in a string

Question

Can seem to find a substring function in python.

Say I want to output the first 100 characters in a string, how can I do this?

I want to do it safely also, meaing if the string is 50 characters it shouldn't fail.

Answer 1

print my_string[0:100]

Answer 2

Easy:

print mystring[:100]

Answer 3

substr = string[:100]

Answer 4

Slicing and dicing sequences (including strings) is an important part of Python. The following resources will come in handy:

1. http://docs.python.org/tutorial/introduction.html
2. http://diveintopython.org/native_data_types/lists.html

Answer 5

From python tutorial:

Degenerate slice indices are handled gracefully: an index that is too large is replaced by the string size, an upper bound smaller than the lower bound returns an empty string.

So it is safe to use x[:100].

Answer 6

Slicing of arrays is done with [start:end+1].

One trick I tend to use a lot of is to indicate extra information with ellipses. So, if your field is one hundred characters, I would use:

if len(s) <= 100:
    print s
else:
    print "%s..."%(s[:97]) # Yes, I know () is superfluous, it's just my style.

Answer 7

To answer Philipp's concern ( in the comments ), slicing works ok for unicode strings too

>>> greek=u"αβγδεζηθικλμνξοπρςστυφχψω"
>>> print len(greek)
25
>>> print greek[:10]
αβγδεζηθικ

If you want to run the above code as a script, put this line at the top

# -*- coding: utf-8 -*-

If your editor doesn't save in utf-8, substitute the correct encoding