What will the output of print("\\") be?

The output of the expression print("\\") will indeed be two backslashes: \\. In Python, the backslash (\) is an escape character used to indicate that the following character has a special meaning. For example, "\n" represents a newline, and "\t" represents a tab.

When a single backslash is used in a string, it needs to be escaped to actually represent a literal backslash in the output. Therefore, to include a single backslash in the printed result, you need to use two backslashes in the string to tell Python to treat it as a character rather than an escape character.

Consequently, print("\\") effectively tells Python to interpret the two backslashes as one literal backslash in the output, so it prints one backslash, which is correctly interpreted as two characters in the source code but results in a single backslash being displayed. This means that the output is \, and it appears as \\ in the code.

This understanding is crucial in programming, especially when dealing with string formatting or paths in programming languages.