1. 问题背景

您需要在多个文件中替换所有特定字符串的实例。例如，您有一个包含 60728 个键值对的映射词典，需要处理多达 50 个文件，每个文件大约有 250000 行，并且需要在每行中替换多个键。

2. 解决方案

方法一：使用正则表达式

import sys, re, time, hashlib

class Regex:

    # Regex implementation of find/replace for a massive word list.

    def __init__(self, mappings):
        self._mappings = mappings

    def replace_func(self, matchObj):
        key = matchObj.group(0)
        if self._mappings.has_key(key):
            return self._mappings[key]
        else:
            return key

    def replace_all(self, filename):
        text = ''
        with open(filename, 'r+') as fp
            text = fp.read()
        text = re.sub("[a-zA-Z]+", self.replace_func, text)
        fp = with open(filename, "w") as fp:
            fp.write(text)

# mapping dictionary of (find, replace) tuples defined 
mappings = {'original-1': 'replace-1', 'original-2': 'replace-2'}

# initialize regex class with mapping tuple dictionary
r = Regex(mappings)

# replace file
r.replace_all( 'file' )

方法二：使用多进程

import multiprocessing as mp

def split_seq(seq, num_pieces):
    # Splits a list into pieces
    start = 0
    for i in xrange(num_pieces):
        stop = start + len(seq[i::num_pieces])
        yield seq[start:stop]
        start = stop   

def detect_active_keys(keys, data, queue):
    # This function MUST be at the top-level, or
    # it can't be pickled (multiprocessing using pickling)
    queue.put([k for k in keys if k in data])

def mass_replace(data, mappings):
    manager = mp.Manager()
    queue = mp.Queue()
    # Data will be SHARED (not duplicated for each process)
    d = manager.list(data) 

    # Split the MAPPINGS KEYS up into multiple LISTS, 
    # same number as CPUs
    key_batches = split_seq(mappings.keys(), mp.cpu_count())

    # Start the key detections
    processes = []
    for i, keys in enumerate(key_batches):
        p = mp.Process(target=detect_active_keys, args=(keys, d, queue))
        # This is non-blocking
        p.start()
        processes.append(p)

    # Consume the output from the queues
    active_keys = []
    for p in processes:
        # We expect one result per process exactly
        # (this is blocking)
        active_keys.append(queue.get())

    # Wait for the processes to finish
    for p in processes:
        # Note that you MUST only call join() after
        # calling queue.get()
        p.join()

    # Same as original submission, now with MUCH fewer keys
    for key in active_keys:
        data = data.replace(k, mappings[key])

    return data

if __name__ == '__main__':
    # You MUST call the mass_replace function from
    # here, due to how multiprocessing works
    filenames = <...obtain filenames...>
    mappings = <...obtain mappings...>
    for filename in filenames:
        with open(filename, 'r+') as f:
            data = mass_replace(f.read(), mappings)
            f.seek(0)
            f.truncate()
            f.write(data)

方法三：使用 Trie

tree = ahocorasick.KeywordTree()
for key in mappings:
    tree.add(key)
tree.make()    
for start, end in reversed(list(tree.findall(target))):
    target = target[:start] + mappings[target[start:end]] + target[end:]

这三个解决方案可以帮助您更快地比较和替换键值对。您可以根据自己的需求选择最合适的方法。