Python binary file search

File handling – Binary file operations in Python – Search, Append, Update and Delete Records

In this article, you will learn about File handling – Binary file operations in Python such as Append, Search, update and delete.

In the previous article, you learned about Basic operations on a binary file such as opening/closing a binary file, the fundamentals of the pickle module and reading and writing in binary files.

So let’s start now, the contents are as follows:

Append data in Binary File

1. Open the file in append mode using “ab” Ex.: f = open (“file.dat”,”ab”)
2. Enter data to append
3. Append entered data into the dictionary/list object
4. Use pickle.dump() method to write the dictionary/list data
5. Close the file

def bf_append(): f = open("sports.dat","ab") print("Append Data") pcode = int(input("Enter the Player code:")) pname = input("Enter Player Name:") score = int(input("Enter individual score:")) rank = int(input("Enter Player Rank:")) rec= pickle.dump(rec,f) f.close() bf_append()

Do not run your code without reading the contents.

Reading Data

1. Open the file in read mode using “rb” Ex.: f = open(“File.dat”, “rb”)
2. Use while loop with True statement to read the entire contents of the file individually.
3. Use try – except for Exception handling to avoid runtime EOFError
4. Now load data into an object through the load function
5. Print data as per need
6. Close the file

Observe the following code:

def bf_read(): f = open("Sports.dat","rb") print("*"*78) print("Data stored in File. ") while True: 
try: rec= pickle.load(f) print("Player Code:",rec['Pcode']) print("Player Name:",rec['Pname']) print("Individual Score:",rec['Score']) print("Player Rank:",rec['Rank']) print("."*78) except Exception: 
break f.close() bf_read() 

Watch this video to append and display a record using list object into binary file.

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Python binary file search

Comparison with other Searching

Some problems on Binary Search

• Check if an array is sorted and rotated using Binary Search
• Longest Common Prefix using Binary Search
• Find the Peak Element in a 2D Array/Matrix
• Search an element in a sorted and rotated array with duplicates
• Search for an element in a Mountain Array
• Median of two Sorted Arrays of Different Sizes
• Longest Increasing Subsequence Size (N log N)
• Median of two Sorted Arrays of Different Sizes using Binary Search
• The Painter’s Partition Problem using Binary Search
• Allocate Minimum Number of Pages from N books to M students
• Find largest median of a sub array with length at least K

Variants of Binary Search

Comparison with other Searching

Some problems on Binary Search

• Check if an array is sorted and rotated using Binary Search
• Longest Common Prefix using Binary Search
• Find the Peak Element in a 2D Array/Matrix
• Search an element in a sorted and rotated array with duplicates
• Search for an element in a Mountain Array
• Median of two Sorted Arrays of Different Sizes
• Longest Increasing Subsequence Size (N log N)
• Median of two Sorted Arrays of Different Sizes using Binary Search
• The Painter’s Partition Problem using Binary Search
• Allocate Minimum Number of Pages from N books to M students
• Find largest median of a sub array with length at least K

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Python binary file search

Note: Binary files are always written in structure form and later it is converted to byte stream before storing to binary file. By structure from I mean to say in formats like lists, tuple, sets, dictionary etc.

Searching Records in Binary File: There is no any pre-defined function available in python for searching records in binary file in python. We will define our logic or function to solve our problem of updating records.

Important: We will search records from our existing file “bin.dat” having some data written to it. So, below is our raw file with data.

file: “ bin.dat ”

We will update the information of student with roll number ‘1602’

Problem Solving Approach: Binary file always stores multiple data in nested list or any nested structure form, so that our file “ bin.dat ” is storing. Inside our list there is sub lists are also there and we have to search from that sub list. So simply we will use for loop() to iterate each sub list and then we will perform required operation on each entities of sub list.

Explanations: Solution of our problem is divided into four easy steps. Also we can see that we have successfully found the third record of our file. Below the program explanation is given:

Step 1: Here we have defined read() function, just to check the records available in our binary file.

Step A: Here this is our main search() function that we have defined to solve our problem. Inside this, we have further sub divided the problem solution in three steps (2,3,4).

Step 2: Here file “bin.dat” is opened in “rb” mode which is for reading binary file. Also we have load the data of our file in file object named “s“ and defined initialized “final” variable with value 0. And asking roll number as input from user whose entry user wants to search and we are storing that input value in “rn” variable.

Step 3: Here for loop we used to iterate over each sub-list of list. So after successful execution of step 2, next execution will enter to for loop. Here each sub list is iterated and assign to “i” one by one. Now, if condition will check for, is the value inside “rn” matches with value available at i[0] index ?

Important: Actually “i” is storing the sub-list ie. [1600,”Raj”,20]. so here value of i[0] is 1600. Hence each roll number is checked.

If any of roll number is matched with the value. Then the next step is to display the information available in our file to user. We have found the roll number that user wants to search so now we will also break the for loop and set the value of “final” variable to 1.

Step 4: At this step we have again set the value of “final” variable to 0 and print message as no record found. This is because in step 3 user will only enter inside if condition only if value of rn is matched with any of record available inside sub-list else execution jump to step 4.

Hence this is the way to search records from a binary file in python.

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Search within binary files for a string, hex, or even another binary file

Sepero/SearchBin

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README

SearchBin is a fast commandline program for searching within binary files. It's a bit like grep for binaries. It has three capabilities for searching. -Search for bytes using hexidecimal -Search for a plain text string -Search for a smaller binary file Syntax: searchbin.py -t PATTERN [FILE [FILE. ]] searchbin.py -p PATTERN [FILE [FILE. ]] searchbin.py -f FILE [FILE [FILE. ]] EXAMPLES Search for the hex bytes "FF14DE" in the file gamefile.db: $ ./searchbin.py -p "FF14DE" gamefile.db Match at offset: 907 38B in gamefile.db Match at offset: 1881 759 in gamefile.db Match at offset: 7284 1C74 in gamefile.db Match at offset: 7420 1CFC in gamefile.db Match at offset: 8096 1FA0 in gamefile.db The printed offsets are listed in decimal and hexidecimal formats. You can also search for unknown patterns with "??". Just insert them where ever you have an unknown byte: $ ./searchbin.py -p "FF??DE" gamefile.db You can search through multiple files at once, and search piped input: $ ./searchbin.py -p "FF??EE" gamefile.db supersecret.idx $ cat gamefile.db | ./searchbin -p "FF??EE" You can also search using regular text strings and other binary files. $ ./searchbin.py -t "hello" gamefile.db $ ./searchbin.py -f binaryfile gamefile.db Options of SearchBin: $ ./searchbin.py --help Optional Arguments: -h, --help show help message and exit -f FILE, --file FILE file to read search pattern from -t PATTERN, --text PATTERN a (non-unicode case-sensitive) text string to search for -p PATTERN, --pattern PATTERN a hexidecimal pattern to search for -b NUM, --buffer-size NUM read buffer size (in bytes). default is 8388608 (8MB) -s NUM, --start NUM starting position in file to begin searching -e NUM, --end NUM end search at this position, measuring from beginning of file -m NUM, --max-count NUM maximum number of matches to find -l FILE, --log FILE write matched offsets to FILE, instead of standard output -v, --verbose verbose, output the number of bytes searched after each buffer read -V, --version print version information Extra Notes: An argument -t or -p or -f is required. The -p argument accepts a hexidecimal pattern string and allows for missing characters, such as 'FF??FF'. When using -f argument, the pattern file will be read as a binary file (not hex strings). If no search files are specified, %prog will read from standard input. The minimum memory required is about 3 times the size of the pattern byte length. Increasing buffer-size will increase program search speed for large search files. All size arguments (-b -s -e) are read in decimal format, for example: '-s 1024' will start searching after 1kilobyte. Pattern files do not allow for wildcard matching. Reported matches are displayed as 0-based offset. Further Examples: Search for the text string "Tom" in myfile.exe. Text is case sensitive. ./searchbin.py -t "Tom" myfile.exe Search for the text string "T?m" in myfile.exe, where ? is a wildcard. This will match "Tom" "Tim" "Twm" and all other variations, including non-printing bytes. ./searchbin.py -t "T?m" myfile.exe Search for the hexidecimal pattern "AABBCCDDEE" in myfile.exe. ./searchbin.py -p "AABBCCDDEE" myfile.exe Searches for the hexidecimal pattern "AA??CC??EE" in myfile.exe, where ?? can be any byte value. ./searchbin.py -p "AA??CC??EE" myfile.exe Takes the binary file pattern.bin, and searches for an exact match within myfile.exe. ./searchbin.py -f pattern.bin myfile.exe Features: +No compiling necessary +Requires Python 2.7 or Python 3 +Less code +Search in files of unlimited size keywords: hex hexidecimal binary like grep search seek find fast Please report bugs & feature requests to sepero 111 @ gmx . com or https://github.com/Sepero/SearchBin/issues or http://seperohacker.blogspot.com/2012/04/binary-grep-program-searchbin.html NOTE: This program is no longer being maintained. I attempted to make the code easily readable and well documented. Please fork it and make something even greater!

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Search within binary files for a string, hex, or even another binary file

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