在txt文件中搜索字符串/否则打印不存在

Question

I am having an issue where I'm trying to write a program that combs a config file for 'certain' search terms and if they match, print "it's there", if not print "it's not here". Here is what I have so far:

import sys
import fnmatch
import re

check = ["test1", "test2", "test3"]

 for f in filter(os.path.isfile, sys.argv[1:]): ##open doc arg
    for line in open(f).readlines(): ##loop for reading line by line
        if re.match(check[0], line): ##match at beginning for check
            print(check[0], "is in place") ##print if match == true
        elif re.search(check[0], line): ##if not check search (full file)
            print(check[0], "is not in place") ##print if true
    for line in open(f).readlines():
        if re.match(check[1], line):
            print(check[1], "is in place")
        elif ((re.search(check[1], line)) == None):
            print(check[1], "is not in place")

So the issue is, if I print an else-statement, then every line (all 1500) prints since the loop runs line by line. Is there a way to search the whole doc and not line by line?

Answer 1

Yes, this is possible, using read() . But beware that if your file is huge, it may not be a good idea to load the entire file at once in your memory.

Also you are looping through the same file multiple times, try to avoid this by only iterating over the file once and searching all the values in the check array at once. Furthermore try to avoid using regexes whenever possible since they can be slow. Something like this can work too:

for line in open(f).readlines():
    for check_value in check:
        if check_value in line:
            print "{} is in place.".format(check_value)

Answer 2

Use the else clause of the for loop along with the break statement. Also note that just iterating over the file itself will do; no need to explicitly read all the lines. (I also added with to make sure the file gets closed.)

with open(f) as infile:
    for line in infile:
        if re.match(check[0], line):
            print(check[0], "is in place")
            break     # stop after finding one match
    else:             # we got to the end of the file without a match
        print(check[0], "is not in place")

You can even write it as one of those ever-popular generator expressions:

with open(f) as infile:
    if any(re.match(check[0], line) for line in infile):
        print(check[0], "is in place")
    else:
        print(check[0], "is not in place")

Since the messages being printed are so similar, you can code-golf it even further:

with open(f) as infile:
    print(check[0], "is" if any(re.match(check[0], line) for line in infile) else "is not", "in place")

Answer 3

To read the entire file, you can use read() instead of readlines() .

with open(f) as fil:
    lines = fil.read()

If what you're looking for in the file is just a string, you don't need re :

if check[0] in lines:
    print(check[0], "is in place")

Answer 4

I guess you can read the file to a string and use a simple if x in... , ie:

with open("text_contains.txt") as f:
    text =  f.read().lower() # remove .lower() for caseSensiTive matching
for x in ["test1", "test2", "test3"]:
    if x in text:
        print("{} is in place".format(x))
    else:
        print("{} is not in place".format(x))

Answer 5

If you really need to read the file line by line (I assume you need the line of the occurrence), then:

import sys
import fnmatch
import re

searchTerms = ["test1", "test2", "test3"]
occurrences = {}

# Initialise occurrences list for each term:

for term in searchTerms:
    occurrences[term] = []

# Read line by line and check if any of the terms is present in that specific
# line. If it is, save the occurrence.

for f in filter(os.path.isfile, sys.argv[1:]):
    for line in open(f).readlines():
        for term in searchTerms:
            if re.match(term, line):
                occurrences[term].append(line)

# For each term, print all the lines with occurrences, if any, or 'not found'
# otherwise:

for term in searchTerms:
    if len(occurrences[term]) > 0:
        print("'%s' found in lines: %s" % ", ".join(occurrences[term]))
    else:
        print("'%s' not found" % term)

However, if you just need to check if the term is there, regardless of the line, just use read to read the whole file at once:

for f in filter(os.path.isfile, sys.argv[1:]):
    with open(f) as file:
        text = file.read()

        for term in searchTerms:
            if re.match(term, text):
                print("'%s' found" % term)
            else:
                print("'%s' not found" % term)