如何将一个字符串拆分为五个？

Question

So the program would read a file with a string. That string would then be saved to another file but the string would be split into groups of 5.

Example.

Given that the content of file1.txt will be thecatsatonthemat , the content of file2.txt would then be theca tsato nthem at .

Answer 1

Here is an enumerator that will give you 5 character chunks:

def chunk(l):
    for i in range(0, len(l), 5):
        yield l[i:i+5]

Use it like:

>>> l = 'abcdefghijqlmnopqrstuvwxyz'
>>> for sub in chunk(l):
>>>     print(sub)

abcde
fghij
klmno
pqrst
uvwxy
z

Answer 2

Something like this ?

>>> a = "123456789012345678901234567890"
>>> while len(a)>0:
...     print a[0:5]
...     a=a[5:]
...
12345
67890
12345
67890
12345
67890

Answer 3

Contents of file data.txt thecatsatonthemat

with open('data.txt', 'r') as f:
    data = f.read()
new_string = ''
for i,val in enumerate(data):
    if i%5 == 0 and i != 0:
        new_string += ' ' + val
    else:
        new_string += val
with open('new_data.txt', 'w') as f:
    f.write(new_string)

Contents of new_data.txt

theca tsato nthem at

Answer 4

You can do something like this. file1.txt will be the file where the string is retrieved. file2.txt will be the file where the split string will be written.

NOTE: This code assumes that the text file (file1.txt) doesn't have white spaces or newlines.

line = ''
with open('file1.txt', 'r') as fr:
    line = fr.read()
fr.close()

modified_str = ''
for i in range(0, len(line), 5):
    modified_str += line[i:i + n] + ' '
modified_str = modified_str[:len(modified_str) - 1] # Remove the trailing white space

with open('file2.txt', 'w') as fw:
    fw.write(modified_str)
fw.close()

Let us assume that the contents of file1.txt is thecatsatonthemat . Running that code, file2.txt will now contain theca tsato nthem at .

Answer 5

If you have the string in memory and you need the output in memory, use Steven Burnap's answer.

If you need to read and write files, here is a fast solution which uses little ( O(1) ) memory, and works in Python 2 and 3:

with open('file1.txt') as f:
  with open('file2.txt', 'w') as nf:
    item = f.read(5)
    nf.write(item)
    while len(item) == 5:
      item = f.read(5)
      if not item:
        break
      nf.write(' ')
      nf.write(item)