append

问题 I am sorry but I am new in Python and I have file which have data like this x1 y1 z1 w1 x2 y2 z2 w2 .. xn yn zn wn I would like to append some number after every w. so basically after every 4th element in the txt file. Is there any recommendations please? Thanks a lot Update : The data which is in the txt file are all strings. I was able to convert them f = open("test.txt","r+").readlines() for line in f: tmp = line.strip().split(",") values = [float(v) for v in tmp] my_data = [1 1 2 23 1] a

问题 I am sorry but I am new in Python and I have file which have data like this x1 y1 z1 w1 x2 y2 z2 w2 .. xn yn zn wn I would like to append some number after every w. so basically after every 4th element in the txt file. Is there any recommendations please? Thanks a lot Update : The data which is in the txt file are all strings. I was able to convert them f = open("test.txt","r+").readlines() for line in f: tmp = line.strip().split(",") values = [float(v) for v in tmp] my_data = [1 1 2 23 1] a

问题 I want to append a list/1d array (b) at the end of each row of a 2d array (a) input: a = np.array([[1, 1], [2, 2], [3, 3]]) b = np.array([4, 4]) desired out: array([[1, 1, 4, 4], [2, 2, 4, 4], [3, 3, 4, 4]]) my code: temp = [] for i in range(len(a)): c = np.hstack((a[i], b)) temp.append(c) d = np.vstack(temp) is there any better and fast solution for this. 回答1: a = np.array([[1, 1], [2, 2], [3, 3]]) b = np.array([4, 4]) c = np.tile(b[np.newaxis,:], (a.shape[0],1)) d = np.concatenate((a,c),

问题 Asume that I have the following dataframe: d = {'col1': [1, 2], 'col2': [3, 4]} df = pd.DataFrame(data=d) I would like to extend col1 with array xtra . However this errors out. xtra = [3,4] df['col1'].append(xtra) How can I append xtra to df.col1 , so that the final otuput would looks as so? col1 col2 0 1 3 1 2 4 2 3 nan 3 4 nan 回答1: just copy the same format you used ( dict ) to make a dataframe like so: import pandas as pd d = {'col1': [1, 2], 'col2': [3, 4]} df = pd.DataFrame(data=d) xtra

问题 I have a form for end users, and in one section of the form they will need to append rows to continue to add their data. No matter how many rows I append or post, whether it's 2, 5, or 10, only the last row of data makes it to the database. TABLE STRUCTURE sub_name sub_tests sub_dx Jimmy's Deli 11 3 Sally's Shop 31 2 APPEND SCRIPT <script type="text/javascript"> $(document).ready(function(){ var i=1; $('#add').click(function(){ i++; $('#dynamic_field').append('<tr id="row'+i+'" class="dynamic

问题 I'm extending my original question here: How to append/merge list of dictionaries?. I'm trying to merge some data between a single List of dictionaries that has lists inside. Merging would happen based on the "object" and "semver" key if they matched. Also adding to their given "section" if the same value was matched. Given the following data: data = [ { "semver":"1.0.0", "sections":[ { "name":"Add", "messages":[ "add: comment here" ] } ], "object":"files.sh" }, { "semver":"1.0.0", "sections"

问题 I'm extending my original question here: How to append/merge list of dictionaries?. I'm trying to merge some data between a single List of dictionaries that has lists inside. Merging would happen based on the "object" and "semver" key if they matched. Also adding to their given "section" if the same value was matched. Given the following data: data = [ { "semver":"1.0.0", "sections":[ { "name":"Add", "messages":[ "add: comment here" ] } ], "object":"files.sh" }, { "semver":"1.0.0", "sections"

问题 What's the best way to insert new rows into an existing pandas DataFrame while maintaining column data types and, at the same time, giving user-defined fill values for columns that aren't specified? Here's an example: df = pd.DataFrame({ 'name': ['Bob', 'Sue', 'Tom'], 'age': [45, 40, 10], 'weight': [143.2, 130.2, 34.9], 'has_children': [True, True, False] }) Assume that I want to add a new record passing just name and age . To maintain data types, I can copy rows from df , modify values and

问题 I'm trying to merge some data between a single List of dictionaries that has lists inside. Merging would happen based on the "object" key if they matched. Also adding to their given "section" if the same value was matched. Given the following data: data = [ { "semver":"1.0.0", "sections":[ { "name":"Add", "messages":[ "add: comment here" ] } ], "object":"files.sh" }, { "semver":"1.0.0", "sections":[ { "name":"Add", "messages":[ "add: Second comment here" ] } ], "object":"files.sh" }, {

问题 Why does this statement produce an error even though a string is actually a list of character constants? string_name = "" string_name.append("hello word") The reason I expect this to work is because when we use for-loop, we are allowed to use this statement: for i in string_name: ... I think string_name is considered as a list here(?) 回答1: That's what they teach you in algorithms and data structures class, who deal with algorithmic languages (unreal) rather than real programming languages, in