Learning Python(First Day)

Abstract: Basic Operation of Jupyter, Output, Input, Slicing of String, Basic Function and Some Tips

1. Basic Operation of Jupyter

   1. ctrl+enter

      It means that run codes only in this cell.

   2. shift+enter

      It means that run codes only in this place and create a new space below this cell.

   3. restart

      It is similar to ‘F5’ in Windows.

   4. insert

      It indicates that create a new cell above current cell or below current cell.

2. Output

print(" Hello world")
           

1. Input

sentence = input()
           

4.Slicing of String

sample_string = "I am the best"
print(sample_string[0]) # the first word in the string numbers 0
print(sample_string[1])
print(sample_string[2])

# The words in string can not only be summarized by positive number, but can be also summarized by nagtive number
print(sample_string[-1]) # It equals sample_string[12] in this string
print(sample_string[-5])

           

#Slicing a substring 
print(sample[1:8]) # It means that printing from the second word( represented by '1') to the seventh word ( '8-1 = 7')
print(sample[ :8])  # It means that printing from the beginning word to the seventh word
print(sample[1: ])  # It means that printing form the second word to the end
print(sample[1:8:2]) # It means that printing from the second word to the seventh word with 2 steps
print(sample[1:8:-1])  #It means that reversing the string
#Remember, the number can not exclude the specific range.
           

1. Some basic function

word = sample_string[0]
word.isalpha()  # check whether the letter is alpha or not
word.lower()  # such as A to a
word.upper() # such as a to A
str_length = len(sample_string) # the length of the string  
           

1. Tips

   From floating to integer, it will ignore the number behind the dot.