Python Notes - Strings

Python Notes

String Methods

• string.capitalize() 

Capitalized first letter of string.

•  string.strip() 

Strips whitespaces both left and right side.

•  string.lstrip() 

Strips whitespaces left side

• string.rstrip() 

Strips whitespaces right side

•  string.lower() 

turns string into lower case

•  string.upper() 

turns string into upper case

•  string.split() 

Split string into array

String Formatting

Formatting using %{s,i}

    	
          In [24]: import time

          In [25]: time.strftime("%H:%M:%S")
          Out[25]: '21:19:12'

          In [26]: # Method 1

          In [27]: print("Hello %s, current time is %s" % ("Raja", time.strftime("%H:%M:%S")))
          Hello Raja, current time is 21:20:22

          In [28]: # Method 2

          In [30]: print("Hello %(name)s, current time is %(time_now)s" % { "name" : "Raja", "time
              ...: _now" : time.strftime("%H:%M:%S") })
          Hello Raja, current time is 21:22:19

          In [31]:
		
	

Formatting Using .format()

      In [31]:  ## Using .format()

      In [32]: "Hello {} , current time {}".format("Raja", time.strftime("%H:%M:%S"))
      Out[32]: 'Hello Raja , current time 21:27:23'

      In [33]: "Hello {0} , current time {1}".format("Raja", time.strftime("%H:%M:%S"))
      Out[33]: 'Hello Raja , current time 21:27:38'


      In [36]: "Hello {u_name} , current time {time_now}".format(u_name = "Raja", time_now = t
          ...: ime.strftime("%H:%M:%S"))
      Out[36]: 'Hello Raja , current time 21:29:01'


      In [38]: "Hello {u_name} , current time {time_now}".format(**{"u_name" : "Raja", "time_n
          ...: ow" : time.strftime("%H:%M:%S")})
      Out[38]: 'Hello Raja , current time 21:31:32'

      In [39]: ## Alignment

      In [41]:
          ...: "{:>200}".format("Right arrow, right aligned, so 20 spaces, then aligned to rig
          ...: ht")
      Out[41]: '                                                                                                                                         Right arrow, right aligned, so 20 spaces, then aligned to right'

      In [42]:
          ...: "{:>200}".format("Right arrow, right aligned, so 200 spaces, then aligned to ri
          ...: ght")
      Out[42]: '                                                                                                                                        Right arrow, right aligned, so 200 spaces, then aligned to right'


      In [45]:
          ...: "{:^20}".format("aligned center")
      Out[45]: '   aligned center   '
      

Formatting Using F-Strings

        In [46]: ### F-Strings


        In [48]: def current_time() :
            ...:   return time.strftime("%H:%M:%S")
            ...:

        In [49]: current_time()
        Out[49]: '21:39:08'

        In [51]: name = "Raja"

        In [52]: f'Hello {name}, currne time is {current_time()}'
        Out[52]: 'Hello Raja, currne time is 21:40:03'

        In [53]: f' f-strings can do eval expressions as well {2+3}'
        Out[53]: ' f-strings can do eval expressions as well 5'

        In [54]: f'Hello {name.lower()}'
        Out[54]: 'Hello raja'

        In [55]: username = "Raja"

        In [56]: f'You {username=}'
        Out[56]: "You username='Raja'"

        In [57]:
	
    

String Slicing

  
  	In [61]: "this is a string"[5:10]
	Out[61]: 'is a '
  
  

String cancatenation

  
  In [62]: name = "Raja"

  In [63]: lname = "Genupula"

  In [64]: name + lname
  Out[64]: 'RajaGenupula'

  In [65]: name +" " + lname
  Out[65]: 'Raja Genupula'

  In [67]: " ".join([name, lname])
  Out[67]: 'Raja Genupula'

  In [68]: ", ".join([name, lname])
  Out[68]: 'Raja, Genupula'

  In [69]:
  
  

I hope by looking at the code and output, you can understand whats happening, if more explanation needed, please add in comments.

Thank you