Python文件字符串替换字典和元组

Question

have a Dict with multiple values in a tuple.

newhost = {'newhost.com': ('1.oldhost.com',
                   '2.oldhost.com',
                   '3.oldhost.com',
                   '4.oldhost.com')
        }

I wanna open a existing file and search for lines in this file that contains a value of the oldhosts. A file can have multiple Account Lines. In example Account: 1.oldhost.com username Account: someotherhost username When the line with 1.oldhost.com or 2.oldhost.com or 3.oldhost.com and so on is found i wanna replace it with the key form the dict newhost.com.

Can anyone help me? Searched alot, but didnt find the right thing.

Regards

Answer 1

Maybe something like this could get you started

infile_name = 'some_file.txt'
# Open and read the incoming file
with open(infile_name, 'r') as infile:
    text = infile.read()

# Cycle through the dictionary
for newhost, oldhost_list in host_dict.items():
    # Cycle through each possible old host
    for oldhost in oldhost_list:
        text.replace(oldhost, newhost)

outfile_name = 'some_other_file.txt'
# Write to file
with open(outfile_name, 'w') as outfile:
    outfile.write(text)

Not claiming this to be the best solution, but it should be a good start for you.

Answer 2

To easily find the new host for a given old host, you should convert your data structure:

# your current structure
new_hosts = {
    'newhost-E.com': (
        '1.oldhost-E.com',
        '2.oldhost-E.com',
    ),
    'newhost-A.com': (
        '1.oldhost-A.com',
        '2.oldhost-A.com',
        '3.oldhost-A.com',
    ),
}

# my proposal
new_hosts_2 = {
    v: k
    for k, v_list in new_hosts.items()
    for v in v_list}
print(new_hosts_2)
# {
#     '1.oldhost-E.com': 'newhost-E.com',
#     '2.oldhost-E.com': 'newhost-E.com',
#     '1.oldhost-A.com': 'newhost-A.com',
#     '2.oldhost-A.com': 'newhost-A.com',
#     '3.oldhost-A.com': 'newhost-A.com',
# }

This does repeat the new host names (the values in new_hosts_2 ), but it will allow you to quickly look up given an old host name:

some_old_host = 'x.oldhost.com'
the corresponding_new_host = new_hosts_2[some_old_host]

Now you just need to:

• read the lines of the file
• find the old hostname in that line
• lookup the corresponding new host in new_hosts_2
• replace that value in the line
• write the line to a new file

Maybe like this:

with open(file_name_1, 'r') as fr:
    with open(file_name_2, 'w') as fw:
        for line in fr:
            line = line.strip()
            if len(line) > 0:
                # logic to find the start and end position of the old host
                start_i = ?
                end_i = ?

                # get and replace, but only if its found in 'new_hosts_2'
                old_host = line[start_i:end_i]
                if old_host in new_hosts_2:
                    line = line[:start_i] + new_hosts_2[old_host] + line[end_i:]

                fw.write(line + '\n')

Answer 3

Thank you for your tips. I came up with this now and it is working fine.

import fileinput
textfile = 'somefile.txt'
curhost = 'newhost.com'

hostlist = {curhost: ('1.oldhost.com',
                       '2.oldhost.com',
                       '3.oldhost.com')
                 }

new_hosts_2 = {
    v: k
    for k, v_list in hostlist.items()
    for v in v_list}

for line in fileinput.input(textfile, inplace=True):
    line = line.rstrip()
    if not line:
        continue
    for f_key, f_value in new_hosts_2.items():
        if f_key in line:
            line = line.replace(f_key, f_value)
    print line