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OPS435 Python Lab 5

2 bytes removed, 5 June
PART 2 - Writing To Files
<blockquote style="margin-left:35px;">{{Admon/caution|style="padding-left:25px"|Risk of Losing File Contents|A common problem that new Python programmers may encounter is to accidentally erase existing contents of a file when writing new data to a file. When opening files for writing (using the ''''w'''' open function option), Python assumes existing content in the file is no longer wanted and it's immediately deleted; therefore, if you wish to write data to a file but keep existing content, you need to use the open file option ''''a'''' (append new data to a file).}}</blockquote>
:#When opening a file for writing, the ''''w'''' option is specified with the '''open()''' function. When the 'w' option is specified - previous (existing) contents content inside the file are is deleted. This deletion takes place the moment the open() function is executed, not when writing to th efile. If the file that is being written to doesn't exist - the file will be created upon the file opening process.<br><br>
:#Create a temporary Python file and in there let's open a non-existent file (called file1.txt) for writing:<source lang="python">
f = open('file1.txt', 'w')

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