f-string

来源： https://stackoverflow.com/questions/51308195/how-to-format-f-strings-with-regex-expressions

来源： https://stackoverflow.com/questions/51308195/how-to-format-f-strings-with-regex-expressions

来源： https://stackoverflow.com/questions/63038526/inline-dictionary-as-argument-in-f-string

问题 I'm new here and also new to Python. I wonder what does f in print(f'Column names are {"-".join(row)}') do I tried deleting it and then 'Column names are {"-".join(row)}' become normal string Could you please tell me what does f called, so I can google to learn more about it? Thanks guys. import csv with open('CSV_test.txt') as csv_file: csv_reader = csv.reader(csv_file, delimiter=',') line_count = 0 for row in csv_reader: if line_count == 0: print(f'Column names are {"-".join(row)}') line

问题 While playing with new f-strings in the recent Python 3.6 release, I've noticed the following: We create a foo variable with value bar : >>> foo = 'bar' Then, we declare a new variable, which is our f-string, and it should take foo to be formatted: >>> baz = f'Hanging on in {foo}' Ok, all going fine and then we call baz to check its value: >>> baz 'Hanging on in bar' Let's try to change the value of foo and call baz again: >>> foo = 'spam' >>> baz 'Hanging on in bar' Shouldn't it be dynamic?

问题 In the python document 2.4.3. Formatted string literals, it seems possible to write a star followed by an expression in a f-string's {} , but I cannot find how to use that. What's that and how I can use it? Is it documented somewhere? To be exact, this is regarding "*" or_expr part of the following BNF. f_string ::= (literal_char | "{{" | "}}" | replacement_field)* replacement_field ::= "{" f_expression ["!" conversion] [":" format_spec] "}" f_expression ::= (conditional_expression | "*" or

问题 I have been examining some of my string format options using the new f-string format. I routinely need to unpack lists and other iterables of unknown length. Currently I use the following... >>> a = [1, 'a', 3, 'b'] >>> ("unpack a list: " + " {} "*len(a)).format(*a) 'unpack a list: 1 a 3 b ' This, albeit a bit cumbersome, does the job using pre-3.6 .format notation. The new f-string format option is interesting given runtime string concatenation. It is the replication of the number of {} that

问题 I have been examining some of my string format options using the new f-string format. I routinely need to unpack lists and other iterables of unknown length. Currently I use the following... >>> a = [1, 'a', 3, 'b'] >>> ("unpack a list: " + " {} "*len(a)).format(*a) 'unpack a list: 1 a 3 b ' This, albeit a bit cumbersome, does the job using pre-3.6 .format notation. The new f-string format option is interesting given runtime string concatenation. It is the replication of the number of {} that

问题 I'm wondering how to use an f-string whilst using r to get a raw string literal. I currently have it as below but would like the option of allowing any name to replace Alex I was thinking adding an f-string and then replacing Alex with curly braces and putting username inside but this doesn't work with the r . username = input('Enter name') download_folder = r'C:\Users\Alex\Downloads' 回答1: You can combine the f for an f-string with the r for a literal. user = 'Alex' dirToSee = fr'C:\Users\

问题 I'm trying to write PEP-8 compliant code for a domestic project (I must admit that those are my first steps in the python world) and i've got a f-string that is more than 80 char long - the solid thin line near the dot at self.text is the 80 char mark. (Sorry for the sad link without preview but i must have 10+ rep to post 'em) I'm trying to split it into different lines in the most pythonic way but the only aswer that actually works is an error for my linter Working Code: def __str__(self):