如何删除带空对象的数据行

Question

我有一个具有以下结构的熊猫数据框架

<class 'pandas.core.frame.DataFrame'>
Int64Index: 13 entries, 0 to 12
Data columns (total 8 columns):
 #   Column        Non-Null Count  Dtype 
---  ------        --------------  ----- 
 0   id            13 non-null     object
 1   case_num      13 non-null     int64 
 2   pn_num        13 non-null     int64 
 3   feature_num   13 non-null     int64 
 4   annotation    13 non-null     object
 5   location      13 non-null     object
 6   feature_text  13 non-null     object
 7   pn_history    13 non-null     object

在此数据帧中，注释和位置列有时包含空值，如下所示：

​

​

我希望删除空行，并尝试使用以下命令，但这些操作都不起作用。

df[df['annotation'].str.len() > 0]

df[df['annotation'].map(lambda d: len(d)) > 0]

命令输出

print(df.head(15).to_dict())

如下所示

/*
* 提示：该行代码过长，系统自动注释不进行高亮。一键复制会移除系统注释 
* {'id': {0: '00016_000', 1: '00016_001', 2: '00016_002', 3: '00016_003', 4: '00016_004', 5: '00016_005', 6: '00016_006', 7: '00016_007', 8: '00016_008', 9: '00016_009', 10: '00016_010', 11: '00016_011', 12: '00016_012'}, 'case_num': {0: 0, 1: 0, 2: 0, 3: 0, 4: 0, 5: 0, 6: 0, 7: 0, 8: 0, 9: 0, 10: 0, 11: 0, 12: 0}, 'pn_num': {0: 16, 1: 16, 2: 16, 3: 16, 4: 16, 5: 16, 6: 16, 7: 16, 8: 16, 9: 16, 10: 16, 11: 16, 12: 16}, 'feature_num': {0: 0, 1: 1, 2: 2, 3: 3, 4: 4, 5: 5, 6: 6, 7: 7, 8: 8, 9: 9, 10: 10, 11: 11, 12: 12}, 'annotation': {0: "['dad with recent heart attcak']", 1: '[\'mom with "thyroid disease\']', 2: "['chest pressure']", 3: "['intermittent episodes', 'episode']", 4: "['felt as if he were going to pass out']", 5: '[]', 6: "['adderall', 'adderrall', 'adderrall']", 7: '[]', 8: '[]', 9: "['palpitations', 'heart beating/pounding']", 10: "['3-4 months of']", 11: "['17yo']", 12: "['M']"}, 'location': {0: "['696 724']", 1: "['668 693']", 2: "['203 217']", 3: "['70 91', '176 183']", 4: "['222 258']", 5: '[]', 6: "['321 329', '404 413', '652 661']", 7: '[]', 8: '[]', 9: "['26 38', '96 118']", 10: "['56 69']", 11: "['5 9']", 12: "['10 11']"}, 'feature_text': {0: 'Family-history-of-MI-OR-Family-history-of-myocardial-infarction', 1: 'Family-history-of-thyroid-disorder', 2: 'Chest-pressure', 3: 'Intermittent-symptoms', 4: 'Lightheaded', 5: 'No-hair-changes-OR-no-nail-changes-OR-no-temperature-intolerance', 6: 'Adderall-use', 7: 'Shortness-of-breath', 8: 'Caffeine-use', 9: 'heart-pounding-OR-heart-racing', 10: 'Few-months-duration', 11: '17-year', 12: 'Male'}, 'pn_history': {0: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 1: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 2: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 3: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 4: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 5: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 6: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 7: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 8: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 9: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 10: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 11: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 12: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms'}}
*/

请告诉我如何解决这个问题。

Answer 1

下面是一种基于annotation列来执行您的问题的方法，该列包含的值看起来类似于列表，但实际上是字符串：

df = df[df.annotation.apply(eval).str.len() > 0]

来自示例输入的列annotation (取自问题中的df.head(15) )：

                                    annotation
0             ['dad with recent heart attcak']
1                ['mom with "thyroid disease']
2                           ['chest pressure']
3         ['intermittent episodes', 'episode']
4     ['felt as if he were going to pass out']
5                                           []
6       ['adderall', 'adderrall', 'adderrall']
7                                           []
8                                           []
9   ['palpitations', 'heart beating/pounding']
10                           ['3-4 months of']
11                                    ['17yo']
12                                       ['M']

结果的annotation栏：

                                    annotation
0             ['dad with recent heart attcak']
1                ['mom with "thyroid disease']
2                           ['chest pressure']
3         ['intermittent episodes', 'episode']
4     ['felt as if he were going to pass out']
6       ['adderall', 'adderrall', 'adderrall']
9   ['palpitations', 'heart beating/pounding']
10                           ['3-4 months of']
11                                    ['17yo']
12                                       ['M']

完整测试代码：

import pandas as pd

/*
* 提示：该行代码过长，系统自动注释不进行高亮。一键复制会移除系统注释 
* df = pd.DataFrame({'id': {0: '00016_000', 1: '00016_001', 2: '00016_002', 3: '00016_003', 4: '00016_004', 5: '00016_005', 6: '00016_006', 7: '00016_007', 8: '00016_008', 9: '00016_009', 10: '00016_010', 11: '00016_011', 12: '00016_012'}, 'case_num': {0: 0, 1: 0, 2: 0, 3: 0, 4: 0, 5: 0, 6: 0, 7: 0, 8: 0, 9: 0, 10: 0, 11: 0, 12: 0}, 'pn_num': {0: 16, 1: 16, 2: 16, 3: 16, 4: 16, 5: 16, 6: 16, 7: 16, 8: 16, 9: 16, 10: 16, 11: 16, 12: 16}, 'feature_num': {0: 0, 1: 1, 2: 2, 3: 3, 4: 4, 5: 5, 6: 6, 7: 7, 8: 8, 9: 9, 10: 10, 11: 11, 12: 12}, 'annotation': {0: "['dad with recent heart attcak']", 1: '[\'mom with "thyroid disease\']', 2: "['chest pressure']", 3: "['intermittent episodes', 'episode']", 4: "['felt as if he were going to pass out']", 5: '[]', 6: "['adderall', 'adderrall', 'adderrall']", 7: '[]', 8: '[]', 9: "['palpitations', 'heart beating/pounding']", 10: "['3-4 months of']", 11: "['17yo']", 12: "['M']"}, 'location': {0: "['696 724']", 1: "['668 693']", 2: "['203 217']", 3: "['70 91', '176 183']", 4: "['222 258']", 5: '[]', 6: "['321 329', '404 413', '652 661']", 7: '[]', 8: '[]', 9: "['26 38', '96 118']", 10: "['56 69']", 11: "['5 9']", 12: "['10 11']"}, 'feature_text': {0: 'Family-history-of-MI-OR-Family-history-of-myocardial-infarction', 1: 'Family-history-of-thyroid-disorder', 2: 'Chest-pressure', 3: 'Intermittent-symptoms', 4: 'Lightheaded', 5: 'No-hair-changes-OR-no-nail-changes-OR-no-temperature-intolerance', 6: 'Adderall-use', 7: 'Shortness-of-breath', 8: 'Caffeine-use', 9: 'heart-pounding-OR-heart-racing', 10: 'Few-months-duration', 11: '17-year', 12: 'Male'}, 'pn_history': {0: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 1: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 2: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 3: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 4: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 5: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 6: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 7: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 8: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 9: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 10: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 11: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms', 12: 'HPI: 17yo M presents with palpitations. Patient reports 3-4 months of intermittent episodes of "heart beating/pounding out of my chest." 2 days ago during a soccer game had an episode, but this time had chest pressure and felt as if he were going to pass out (did not lose conciousness). Of note patient endorses abusing adderall, primarily to study (1-3 times per week). Before recent soccer game, took adderrall night before and morning of game. Denies shortness of breath, diaphoresis, fevers, chills, headache, fatigue, changes in sleep, changes in vision/hearing, abdominal paun, changes in bowel or urinary habits. \r\nPMHx: none\r\nRx: uses friends adderrall\r\nFHx: mom with "thyroid disease," dad with recent heart attcak\r\nAll: none\r\nImmunizations: up to date\r\nSHx: Freshmen in college. Endorses 3-4 drinks 3 nights / week (on weekends), denies tabacco, endorses trying marijuana. Sexually active with girlfriend x 1 year, uses condoms'}})
*/

print(df.annotation.to_frame())
df = df[df.annotation.apply(eval).str.len() > 0]
print(df.annotation.to_frame())

Answer 2

使用df.replace()将empty object替换为NaN data，并使用Pandas中的空字符串删除行

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#Convert NaN values to empty string.
nan_value = float("NaN")
df. replace("", nan_value, inplace=True)
df. dropna(subset = ["column2"], inplace=True)
print(df)

输出：

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Answer 3

熊猫有一个非常棒的功能，可以删除所有包含NA值的行，这就是DataFrame.dropna函数：

df = df.dropna()

如果只想删除那些具有所有NA值的行，则可以使用关键字参数how='all'。

df = df.dropna(how='all')