How to use an if else statement in Python

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An if statement in Python has the following structure.

if "foo" in "bar" :
  --do something--
elif :
  --do something--
else :
  --do something

 

For example.

if "foo" in "bar" :
  print ("bar contains foo")
else :
  print ("bar does not contain foo")

 

Following are command if statements.

Equals

tbd

Does not equal

tbd

Greater than

tbd

Less than

tbd

Greater than or equal to

tbd

Less than or equal to

tbd

If file or directory exists

tbd

If variable contains tbd
If variable does not contain tbd
If array contains tbd
If string begins with tbd
If string does not begin with tbd
If string ends with tbd
If string does not end with tbd

 


Ignore case

The i option can be used to ignore case.

tbd

 


Multiple conditions

Multiple conditions can be evaluated by separating each condition with and or or.

tbd

 

More precise conditions can be strung together by evaluating certain conditions together. The possible arrangement of evaluations is literally limitless.

tbd

 

Regular Expressions

Following are commonly used regular expressions.

Single integer (0 through 9)

[0-9]

Single integer followed by anything [0-9]*
Anything followed by a single integer *[0-9]
Single lower case alpha character [a-z]
Single lower case alpha character followed by anything [a-z]*
Anything followed by single lower case alpha character *[a-z]
Single upper case character  [A-Z]
Single upper case alpha character followed by anything [A-Z]*
Anything followed by single upper case alpha character *[A-Z]
Single alpha character [a-zA-Z]
Single alpha character followed by anything [a-zA-Z]*
Anything followed by alpha character *[a-zA-Z]
Any alpha-numeric character [0-9a-zA-Z]
Any alpha-numeric character followed by anything [0-9a-zA-Z]*
Anything followed by any alpha-numeric character *[0-9a-zA-Z]
Any single character except new line .
Any single character except new line followed by anything .*
Space, tab, or newline \s
Not a space, tab, or newline \S
   

 



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