Frequently Used Scripts - python - files, string, dates

In this post:

Python loop files in current folder with listdir
Python loop over files with os.walk()
Split filenames with python
Rename Files
Date format and extraction
Python file read and write
Python strings

You can read also : Frequently Used Scripts - Frequently Used Scripts - python pil

Python loop files in current folder with listdir

Listing files in a single folder by using os.listdir()

import os  

for file in os.listdir('.'):
    if os.path.isfile(file ):
       print (file )

Python loop over files with os.walk()

Listing all files in a folder recursively and subfolders

import os

indir = r'C:\Users\user'
for root, dirs, filenames in os.walk(indir):
   for filename in filenames:
       print (filename)

Split filenames with python

Python getting the file name and folder name for a given file path

import os

file =  'C:\\Users\\user\\Desktop\\test.txt'
print (os.path.basename(file))                      #test.txt
print (os.path.dirname(file))                       #C:\Users\user\Desktop
print (os.path.splitext( file ))                    #('C:\\Users\\user\\Desktop\\test', '.txt')
print (os.path.splitext( os.path.basename(file)))   #('test', '.txt'

result

test.txt
C:\Users\user\Desktop
('C:\\Users\\user\\Desktop\\test', '.txt')
('test', '.txt')

Rename Files

Rename all files starting with examplepattern in current folder with os.rename and remove examplepattern

import os
for filename in os.listdir("."):
   if filename.startswith("examplepattern"):
       os.rename(filename, filename[7:])

before

$ ls
examplepattern_file.txt  examplepattern_file2.txt

after

$ ls
file.txt  file2.foo

Date format and extraction

Python getting today date, adding or subtracting days, date formats:

import time
import datetime

#get today date
today = datetime.date.today()
print ("Today", today )

#date format
print (today.strftime("year: %Y, shor year: %y, month: %m, day: %d") )


#delay
seconds = 3.1
time.sleep(seconds)
print ("boo")

#add 30 days to today
day = datetime.timedelta(days=30)
print ("30 days + today:", today + day)

Python file read and write

Python getting today date, adding or subtracting days, date formats:

#read file 
filePath = "C:\\Users\\user\\Desktop\\test.txt"
for line in open(filePath):
    if 'test' in line:
        print (line[:-1])

#append line to file
#\n is converted as line separator for the OS
with open(filePath, 'a') as file:
    file.write('\nsample data')

#overrite file content and add new line
file = open(filePath, 'w')
file.write('hi there\n')  
file.close()

Python strings

Declaration and usage:

simpleString = "String"   # a newline character
rawString = r"C:\Users\user\test.txt"  # windows path escaped
quotesDouble = "I'm a string"  # single quote in double quotes
quotesSingle = 'I\'m a "string"'  # double quote in single quotes and escaped
#multi lines strings
multiStringDouble = """
line1
line2
line3
"""
multiStringSingle = '''
line4
line5
'''
#String addition
print(multiStringDouble +  multiStringSingle)
#Substring
print(rawString[:5]) #first 5 characters
print(rawString[-10:]) #last 10 characters

#string search
string = 'test'
if string in rawString[-10:]:
    print ("'%s' found in last 10 characters"%string)

#string replace
str = "Java is good, java is clever, java is best"
print (str.replace("java", "python")) #replace all
print (str.replace("java", "python", 1)) #replace first one
#Java is good, python is clever, python is best
#Java is good, python is clever, java is best