Boolean expression:
Boolean: Features: There are only two cases --- True / False
1 -- True False
2 -- type(True) ------------ <class 'bool'>
Boolean expression: 1 --- its bool result
3 2 --- relational operators> == 1 equivalent of an equal sign is the assignment relationship is not equivalent to! =
3 --- compare strings: ① - it is more length? ---- invalid
② - a string comparison is the ASCII value A --- 65 a ---- 97
4 --- logic operation
Boolean result: 1 --- in the inside
2 --- not in not there
3 ---str tuple list
4 ---(1, 3) in (1, 3, 5) --------False
Combination of conditions: 1 - --------- and Condition 1 and Condition 2
Wherein one of ① the entire expression = False False -----
② If the condition 1 == True, conditions 2, will perform
③ If the condition 1 == False, 2 conditions, will not perform
2 - or Condition 1 or Condition 2 ---------
① - one of which is True ----- entire expression = True
② - If the condition 1 == True, conditions 2, will not be executed
③ - If the condition 1 == False, condition 2 will be performed
3 - not - not
① negated True ---- False
4 - Priority
① - without any parentheses case not> and> or
② - the proposed multi-play brackets (3 (2 (1))) ------- from the inside out
③ - complex logic -------- Advisory Notes
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Conditional:
Flow Control: ① a step performed sequentially structure ----
② selection structure ---- perform a selective step
③ ---- loop structure under certain conditions, a piece of code has been executed
Conditional: 1 - if - if the if condition == True: if the implementation of the statements inside
2 - if ... else ... if - else
① only two cases, one of which will certainly be executed
② use the case of opposites
3 - multiple branches if .... elif ... else ...
① optional final else
② as long as one of the branches, exit if the sentence structure
4 - if the Nested
① to be executed if the interior must be outside if it can meet
② equivalent and
5 - switch statement ------------ Without this syntax
6 - multiple conditional branches can write
7-- comment / uncomment ctrl + /
8 - Extended:
① - if followed, if the value is non-empty string, a non-empty tuples, non-empty list is not 0, with the proviso that if the result is True
9 - input () - function - receiving string - returns a string
if statement as long as one code block is terminated if the entire
