搜索文本文件并打印行号

Question

How do you get your function to find the lines in the text file where the word occurs and print the corresponding line numbers?

I had to open a text file with the paragraph and then am supposed to search the paragraph for certain words and then print the specific line numbers for the words.

Here is what I have so far.

words = [network, devices, computer, fire, local, area, room, single]
    def index(string):
       lines = open('Network.txt', 'r')
       string = str(lines.read())
       lines.close()
       return string

Answer 1

Assuming you have opened your file correctly, this is actually quite easy. Using file.read() pulls the entire file in, which you don't want. If you are doing line-based processing, iterate through the file using with as it make opening, closing and error handling of files much easier:

with open(filename) as file:
    for line in file:
        #do something

The core piece with your logic is enumerate() , which takes an iterable and returns a count along with each iterated item.

words = ["word","another"]
for line_num,line in enumerate(file):
    if any([word in line for word in words]):
        print line_num, line

The other factor is the list comprehension which checks if the any word is on a line. The any() function "returns True if any element of the iterable is true". And the following list comprehension:

[word in line for word in words]

can be read as:

[ ^{tell me if} word ^is in ^the line for ^each word in ^{all of the} words] .

If any word is in that array, ie at least one of your words is the line, its true, and thus will be printed.

Answer 2

Use enumerate and a set union of the line in question if you just want to test for presence of individual words:

words={'some', 'target', 'words', 'in', 'a', 'set'}

with open(f_name) as fin:
    for line_num, line in enuemrate(fin):
        if set(line.split()) & words:
            print(line_num, line)

Answer 3

try this:

words = []
lines = {}
for i in words:
    lines[i] = []

with open("file", "r") as fin:
    curLine = 0
    for i in fin.readLines():
        for j in words:
            if j in i:
                lines[j].append(curLine)
        curLine += 1

for i in words:
    print lines[j]