Question

我正在使用Python3来尝试模拟

awk '/STRING/'

我制作了一些可行的代码，但它在第一个实例上停止，而不是查找包含指定字符/字符串的所有行。

在我编写代码之后，我看到了这两个页面，但建议没有用

Print line containing "word" python

Search and get a line in Python

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#Made by Devyn Collier Johnson, NCLA, Linux+, LPIC-1, DCTS
def cat(openfile): #Emulates cat#
    with open(openfile) as file:
        lines = file.readlines()
        return ''.join(lines)
def GETLINEWITH(FILECONTENTS, CONTAINING):
    for item in FILECONTENTS.split('\n'):
        if CONTAINING in item:
            return item.strip()

print(GETLINEWITH(cat('./Base.xaiml'), 'terminal'))

我有一个文件（./Base.xaiml），其中包含单词“terminal”的几个实例。我正在使用此文件和字符串进行测试。

编辑：我还想将结果保存到变量 -

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#Made by Devyn Collier Johnson, NCLA, Linux+, LPIC-1, DCTS
def cat(openfile): #Emulates cat#
    with open(openfile) as file:
        lines = file.readlines()
        return ''.join(lines)
def GETLINEWITH(FILECONTENTS, CONTAINING):
    for item in FILECONTENTS.split('\n'):
        if CONTAINING in item:
            print(item.strip()) #I implemented the give suggestion

VAR = GETLINEWITH(cat('./Base.xaiml'), 'terminal'))

结果：

我试过Jon Clements的建议：

with open('./Base.xaiml') as fin:
    matching = ('terminal' in line for line in fin)
    for line in matching:
        VAR = matching
print(VAR)

但是，输出是一个内存地址。 ''。join（）和group（）没有帮助。

EDIT2：

最新代码问题 - 非类型错误和输出无法保存到变量

#!/usr/bin/env python3
# -*- coding: utf-8 -*-
#Made by Devyn Collier Johnson, NCLA, Linux+, LPIC-1, DCTS
def cat(openfile): #Emulates cat#
    with open(openfile) as file:
        lines = file.readlines()
        return ''.join(lines)
def GETLINEWITH(FILECONTENTS, CONTAINING):
    for item in FILECONTENTS.split('\n'):
        if CONTAINING in item:
            print(item.strip())
for line in GETLINEWITH(cat('./Base.xaiml'), 'terminal'):
    print(line)

Answer 1

在这里，请注意，我只是为您明确地汇总了所有人的评论。

#!/usr/bin/env python3

def cat(openfile):
  with open(openfile) as file:
    return file.read()

def GETLINEWITH(FILECONTENTS, CONTAINING):
  for item in FILECONTENTS.split('\n'):
    if CONTAINING in item:
      yield item.strip()

matchedlines = []

for line in GETLINEWITH(cat('./Base.xaiml'), 'terminal'):
   print(line)
   matchedlines.append(line)

print(matchedlines)

matchedlines变量只是一种将变量匹配的行保存在变量中的方法。

另一个GETLINEWITH实现是：

import re

def GETLINEWITH(FILECONTENTS, CONTAINING):
  for item in FILECONTENTS.split('\n'):
    m = re.search(CONTAINING, item)
    if m:
      yield m.string

可以让你匹配正则表达式。

Answer 2

无论如何 - 它停止的原因＆＃34;是因为你在比赛结束后返回....

def GETLINEWITH(FILECONTENTS, CONTAINING):
    for item in FILECONTENTS.split('\n'):
        if CONTAINING in item:
            return item.strip() # <---- returns as soon as something's found

将其更改为yield以使该函数成为生成器，然后循环它：

for line in GETLINEWITH(cat('./Base.xaiml'), 'terminal'):
    print(line)

最终，你的功能应该是：

with open('thefile') as fin:
    matching = (line for line in fin if 'something' in line)
    for line in matching:
        # do something

或者，将它们全部放入列表中：

lines = list(matching)

Answer 3

文件对象是可迭代的，列表推导可用于过滤输入。

with open('./Base.xaiml','r') as lines:
    matching_lines = [ line.rstrip('\n')
                       for line in lines
                       if line.find('terminal') != -1 ]

for line in matching_lines:
    print line         # change to print(line) for python 3.x

编辑：或者如果你真的希望它成为一个功能

def matching_lines(filename, substring):
    """ Return all the lines in a file that contain a given substring. """
    with open(filename,'r') as f:
        return [s.rstrip('\n') for s in f if s.find(substring) != -1]

for s in matching_lines('./Base.xaiml', 'terminal'):
    print s

打印包含字符串的行：奇怪的行为

3 个答案: