You can wrap the string in a StringIO or BytesIO and pretend it's a file. That should be pretty fast.
from cStringIO import StringIO
# or, in Py3/Py2.6+:
#from io import BytesIO, StringIO
s = StringIO(large_string)
while True:
chunk = s.read(200)
if len(chunk) > 0:
process(chunk)
if len(chunk) < 200:
break
I am new to python how to remove the first character(letter) from a word in python?
python - Equivalent for pop on strings - Stack Overflow
Python Remove last char from string and return it - Stack Overflow
python - Remove the first character of a string - Stack Overflow
string=input("Enter a string: ")How to remove the first letter of the string?
thank you
You can wrap the string in a StringIO or BytesIO and pretend it's a file. That should be pretty fast.
from cStringIO import StringIO
# or, in Py3/Py2.6+:
#from io import BytesIO, StringIO
s = StringIO(large_string)
while True:
chunk = s.read(200)
if len(chunk) > 0:
process(chunk)
if len(chunk) < 200:
break
you can convert the string to a list. list(string) and pop it, or you could iterate in chunks slicing the list [] or you can slice the string as is and iterate in chunks
Strings are "immutable" for good reason: It really saves a lot of headaches, more often than you'd think. It also allows python to be very smart about optimizing their use. If you want to process your string in increments, you can pull out part of it with split() or separate it into two parts using indices:
a = "abc"
a, result = a[:-1], a[-1]
This shows that you're splitting your string in two. If you'll be examining every byte of the string, you can iterate over it (in reverse, if you wish):
for result in reversed(a):
...
I should add this seems a little contrived: Your string is more likely to have some separator, and then you'll use split:
ans = "foo,blah,etc."
for a in ans.split(","):
...
Not only is it the preferred way, it's the only reasonable way. Because strings are immutable, in order to "remove" a char from a string you have to create a new string whenever you want a different string value.
You may be wondering why strings are immutable, given that you have to make a whole new string every time you change a character. After all, C strings are just arrays of characters and are thus mutable, and some languages that support strings more cleanly than C allow mutable strings as well. There are two reasons to have immutable strings: security/safety and performance.
Security is probably the most important reason for strings to be immutable. When strings are immutable, you can't pass a string into some library and then have that string change from under your feet when you don't expect it. You may wonder which library would change string parameters, but if you're shipping code to clients you can't control their versions of the standard library, and malicious clients may change out their standard libraries in order to break your program and find out more about its internals. Immutable objects are also easier to reason about, which is really important when you try to prove that your system is secure against particular threats. This ease of reasoning is especially important for thread safety, since immutable objects are automatically thread-safe.
Performance is surprisingly often better for immutable strings. Whenever you take a slice of a string, the Python runtime only places a view over the original string, so there is no new string allocation. Since strings are immutable, you get copy semantics without actually copying, which is a real performance win.
Eric Lippert explains more about the rationale behind immutable of strings (in C#, not Python) here.
python 2.x
s = ":dfa:sif:e"
print s[1:]
python 3.x
s = ":dfa:sif:e"
print(s[1:])
both prints
dfa:sif:e
Your problem seems unclear. You say you want to remove "a character from a certain position" then go on to say you want to remove a particular character.
If you only need to remove the first character you would do:
s = ":dfa:sif:e"
fixed = s[1:]
If you want to remove a character at a particular position, you would do:
s = ":dfa:sif:e"
fixed = s[0:pos]+s[pos+1:]
If you need to remove a particular character, say ':', the first time it is encountered in a string then you would do:
s = ":dfa:sif:e"
fixed = ''.join(s.split(':', 1))