How do i extract numbers from a file in python?

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Python too supports file handling and allows users to handle files i.e., to read and write files, along with many other file handling options, to operate on files. Data file handling in Python is done in two types of files: 
 

• Text file [.txt extension] 
   
• Binary file [.bin extension] 
   

Here we are operating on the .txt file in Python. Through this program, we can extract numbers from the content in the text file and add them all and print the result.
 

Approach

Reading the contents of the file, we will match the characters’ type against int. If the result of equality is true, then the number will be added to the number stored in the memory allocated to the variable ‘a’. We initiate the variable ‘a’ here with the value 0.
 

Python3

file = open['GFG.txt', 'w']

data ='Geeks1 f2or G8e8e3k2s0'

file.write[data]

file.close[]

Using the above code, we opened a new file named ‘GFG’ in write mode. Using, the write[] function we inserted the data allocated to the variable data in the memory. After this, we closed the file.
Reading from the above-created file and extracting the integers.
 

Python3

h = open['GFG.txt', 'r']

content = h.readlines[]

a = 0

for line in content:

    for i in line:

        if i.isdigit[] == True:

            a += int[i]

print["The sum is:", a]

Output:
 

The sum is: 24

The above program emphasizes on extracting the numbers from the content stored in the text file named ‘GFG’. Furthermore, the numbers are then added after typecasting and stored in the variable ‘a’.
 

This is a Python Program to read a text file and print all numbers present in the text file.

Problem Description

The program takes the name of a file from the user and prints all the numbers present in the text file.

Problem Solution

1. Take the file name from the user.
2. Read each line from the file and split the line to form a list of words.
3. Use a for loop to traverse through the words in the list and another for loop to traverse through the letters in the word.
3. Check if the letter provided by the user is a digit and if it is, print it.
4. Exit.

Program/Source Code

Here is source code of the Python Program to print all the numbers present in a text file. The program output is also shown below.

fname = input["Enter file name: "]
 
with open[fname, 'r'] as f:
    for line in f:
        words = line.split[]
        for i in words:
            for letter in i:
                if[letter.isdigit[]]:
                    print[letter]

Program Explanation

1. User must enter a file name.
2. The file is opened using the open[] function in the read mode.
3. A for loop is used to read through each line in the file.
4. Each line is split into a list of words using split[].
5. A for loop is used to traverse through the words list and another for loop is used to traverse through the letters in the word.
6. If the letter encountered is a digit, the digit is printed.

Runtime Test Cases

 
Case 1:
Contents of file: 
hello world hello5
hello6
 
Output: 
Enter file name: out.txt
5
6
 
Case 2:
Contents of file: 
hello world7
test2
test test8
 
Output: 
Enter file name: out1.txt
7
2
8

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