Php
FILES
p245 Opening a file in write mode clears out old data if the files exists. If the file doesn't exists a new one is created.
CodeCopy
fp = open("/var/www/python/myfile.txt", "w")
fp.write("My new line")
fp.close()
FORMAT
p246 ! The argument of the fwrite() must to be string. If you use % the number and the types in a tuple has to match the format. CodeCopy
no = 24
fp = open("/var/www/python/myfile.txt", "w")
fp.write(str(33))
fp.write("My file has %d lines" % no)
fp.write("There are 3 numbers: %d %d %d" % (1, 2))
# not enough args
fp.close()
... 7 lines˄˄˄OS
p248 ! The os module provides functions for working with files and directories. CodeCopy
import os
cwd = os.getcwd()
print(cwd) # /var/www/python
path = os.path.abspath("test.py")
print(path) # /var/www/python/test.py
... 5 lines˄˄˄ CodeCopy
import os
def walk(dirname):
for name in os.listdir(dirname):
path = os.path.join(dirname, name)
if os.path.isfile(path):
print(path)
else:
walk(path) # calls itself recursively
walk("/var/www/python")
# /var/www/python/test.py
# /var/www/python/calculator.py
# /var/www/python/words.txt
os.walk("/var/www/python") # built-in walk functions
... 13 lines˄˄˄Exceptions
p251 ! A lot of things can go wrong when working with files. Handling an error with try statement is called catching an exception. CodeCopy
try:
fp = open("/var/www/python/") # IsADirectoryError
except:
print("Error: not a file")
... 4 lines˄˄˄➥ Questions
CARD
21
32
