How to join values using join in python-CodePudding

I am trying to build create table statement using python.

my values are stored as following

strsql = ('Col1'   'TEXT'
         , ' col2'   'NUMBER(38, 0)'
         , 'col3'   'TEXT'
         , 'col4'   'TEXT'
         , 'col5'   'TIMESTAMP_NTZ')

and using below to

 print(', '.join(['t.$1:'   i[0] for i in strsql]))

i am getting output as t.$1:C, t.$1:C , t.$1:c, t.$1:c, t.$1:c

expectation: t.$1:Col1, t.$1:col2 , t.$1:col3, t.$1:col4, t.$1:col5

what I am missing in print statement!

CodePudding user response：

The inferred type of the strsql variable is currently a tuple[str, ...].

This happens because 'Col1' 'TEXT' actually concatenates the string into a single string value, like i = 'Col1Text' in this case. Thus, accessing i[0] of this value returns the first character in the string element, or C in this case.

For a simple fix, modify your strsql variable to be a tuple[tuple[str, str], ...] type instead - that is, a tuple of one or more (name, type) elements.

strsql = (('Col1', 'TEXT'),
          (' col2', 'NUMBER(38, 0)'),
          ('col3', 'TEXT'),
          ('col4', 'TEXT'), ('col5', 'TIMESTAMP_NTZ'))

With this change in place, your original print statement now prints the desired result:

t.$1:Col1, t.$1: col2, t.$1:col3, t.$1:col4, t.$1:col5

CodePudding user response：

You access the first character of each string. What you really want is to access the first part.

strsql = (('Col1', 'TEXT'), ('col2', 'NUMBER(38, 0)'), ('col3', 'TEXT'), ('col4', 'TEXT'), ('col5', 'TIMESTAMP_NTZ'))
print(', '.join(['t.$1:'   col for col, _ in strsql]))

CodePudding user response：

You can slice the indiced index of character i[:4]:

strsql = ('Col1' 'TEXT' , 'col2' 'NUMBER(38, 0)' , 'col3' 'TEXT' , 'col4' 'TEXT' , 'col5' 'TIMESTAMP_NTZ')
print(', '.join([f"t.$1:{i[:4]}" for i in strsql]))

# t.$1:Col1, t.$1:col2, t.$1:col3, t.$1:col4, t.$1:col5