Answers for "file in python"

python make txt file

file = open("text.txt", "w") 
file.write("Your text goes here") 
file.close() 
'r' open for reading (default)
'w' open for writing, truncating the file first
'x' open for exclusive creation, failing if the file already exists
'a' open for writing, appending to the end of the file if it exists

python file open modes

r for reading
r+ opens for reading and writing (cannot truncate a file)
w for writing
w+ for writing and reading (can truncate a file)
rb for reading a binary file. The file pointer is placed at the beginning of the file.
rb+ reading or writing a binary file
wb+ writing a binary file
a+ opens for appending
ab+ Opens a file for both appending and reading in binary. The file pointer is at the end of the file if the file exists. The file opens in the append mode.
x open for exclusive creation, failing if the file already exists (Python 3)

python read file

# Basic syntax:
with open('/path/to/filename.extension', 'open_mode') as filename:
  file_data = filename.readlines()	# Or filename.read() 
# Where:
#	- open imports the file as a file object which then needs to be read
#		with one of the read options
#	- readlines() imports each line of the file as an element in a list
#	- read() imports the file contents as one long new-line-separated 
#		string
#	- open_mode can be one of:
#		- "r" = Read which opens a file for reading (error if the file 
#			doesn't exist)
#		- "a" = Append which opens a file for appending (creates the 
#			file if it doesn't exist)
#		- "w" = Write which opens a file for writing (creates the file 
#			if it doesn't exist)
#		- "x" = Create which creates the specified file (returns an error
#			if the file exists)
# Note, "with open() as" is recommended because the file is closed 
#	automatically so you don't have to remember to use file.close()

# Basic syntax for a delimited file with multiple fields:
import csv
with open('/path/to/filename.extension', 'open_mode') as filename:
	file_data = csv.reader(filename, delimiter='delimiter')
    data_as_list = list(file_data)
# Where:
#	- csv.reader can be used for files that use any delimiter, not just
#		commas, e.g.: '\t', '|', ';', etc. (It's a bit of a misnomer)
#	- csv.reader() returns a csv.reader object which can be iterated 
#		over, directly converted to a list, and etc. 

# Importing data using Numpy:
import numpy as np
data = np.loadtxt('/path/to/filename.extension',
				delimiter=',', 	# String used to separate values
				skiprows=2, 	# Number of rows to skip
				usecols=[0,2], 	# Specify which columns to read
				dtype=str) 		# The type of the resulting array

# Importing data using Pandas:
import pandas as pd
data = pd.read_csv('/path/to/filename.extension',
				nrows=5, 		# Number of rows of file to read
				header=None, 	# Row number to use as column names 
	            sep='\t', 		# Delimiter to use 
	            comment='#', 	# Character to split comments
				na_values=[""])	# String to recognize as NA/NaN

# Note, pandas can also import excel files with pd.read_excel()

python file open

#there are many modes you can open files in. r means read.
file = open('C:\Users\yourname\files\file.txt','r')
text = file.read()

#you can write a string to it, too!
file = open('C:\Users\yourname\files\file.txt','w')
file.write('This is a typical string')

#don't forget to close it afterwards!
file.close()

python files

f = open('filename.txt', 'r') #open for reading (default)
f = open('filename.txt', 'w') #open for writing, truncating the file first
f = open('filename.txt', 'x') #open for exclusive creation, failing if the file already exists
f = open('filename.txt', 'a') #open for writing, appending to the end of the file if it exists

python file

>>> f = open('workfile', 'w')